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SERVICE MANUAL
Sec. 1: Main Section
I Specifications I Preparation for Servicing I Adjustment Procedures I Schematic Diagrams I CBA's
Sec. 2: Deck Mechanism Section
I Standard Maintenance I Alignment for Mechanism I Disassembly/Assembly of Mechanism I Alignment Procedures of Mechanism
Sec. 3: Exploded views and Parts List Section
I Exploded views I Parts List
VIDEO CASSETTE RECORDER
25A-254
25A-654
PAL
MAIN SECTION
VIDEO CASSETTE RECORDER 25A-254/25A-654
Sec. 1: Main Section
I Specifications I Preparation for Servicing I Adjustment Procedures I Schematic Diagrams I CBA's
TABLE OF CONTENTS
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1-1 Important Safety Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2-1 Standard Notes for Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3-1 Preparation for Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4-1 Cabinet Disassembly Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5-1 Electrical Adjustment Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6-1 Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7-1 Function Indicator Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7-13 Schematic Diagrams / CBA's and Test Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8-1 Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9-1 Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10-1 IC Pin Function Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11-1 Lead Identifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12-1
SPECIFICATIONS
Description 1. Video 1-1. Video Output (PB) 1-2. Video Output (R/P) 1-3. Video S/N Y (R/P) 1-4. Video Color S/N AM (R/P) 1-5. Video Color S/N PM (R/P) 1-6. Resolution (PB) 2. Servo 2-1. Jitter Low 2-2. Wow & Flutter 3. Normal Audio 3-1. Output (PB) 3-2. Output (R/P) 3-3. S/N (R/P) 3-4. Distortion (R/P) 3-5. Freq. resp (R/P) at 200Hz (-20dB ref. 1kHz) at 6kHz 4. Tuner 4-1. Video output 4-2. Video S/N 4-3. Audio output 4-4. Audio S/N 5. Hi-Fi Audio [ 25A-654 ] 5-1. Output 5-2. Dynamic Range 5-3. Freq. resp (6dB B.W) dBV dB Hz -12 70 -8 85 20 ~ 20K -4 SP Mode SP Mode SP Mode Vp-p dB dB dB 0.8 39 -10 40 1.0 42 -6 46 -2 1.2 E-E Mode E-E Mode E-E Mode E-E Mode dBV dBV dB % dB dB -7 -10 -9 -9 36 -6 -6 41 1.0 -4 -4 4.0 -3 -1.5 SP Mode SP Mode SP Mode SP Mode SP Mode SP Mode µsec % 0.07 0.3 0.12 0.5 SP Mode SP Mode Vp-p Vp-p dB dB dB Line 0.8 0.8 40 37 30 230 1.0 1.0 45 41 36 245 1.2 1.2 SP Mode, W/O Burst SP Mode SP Mode SP Mode FL6A Unit Minimum Nominal Maximum Remark
Note: Nominal specs represent the design specs. All units should be able to approximate these some will exceed and some may drop slightly below these specs. Limit specs represent the absolute worst condition that still might be considered acceptable; In no case should a unit fail to meet limit specs.
1-1-1
HC4C1SP
IMPORTANT SAFETY PRECAUTIONS
Product Safety Notice
Some electrical and mechanical parts have special safety-related characteristics which are often not evident from visual inspection, nor can the protection they give necessarily be obtained by replacing them with components rated for higher voltage, wattage, etc. Parts that have special safety characteristics are identified by a ! on schematics and in parts lists. Use of a substitute replacement that does not have the same safety characteristics as the recommended replacement part might create shock, fire, and/or other hazards. The Product's Safety is under review continuously and new instructions are issued whenever appropriate. Prior to shipment from the factory, our products are carefully inspected to confirm with the recognized product safety and electrical codes of the countries in which they are to be sold. However, in order to maintain such compliance, it is equally important to implement the following precautions when a set is being serviced. I. Also check areas surrounding repaired locations. J. Be careful that foreign objects (screws, solder droplets, etc.) do not remain inside the set. K. Crimp type wire connector The power transformer uses crimp type connectors which connect the power cord and the primary side of the transformer. When replacing the transformer, follow these steps carefully and precisely to prevent shock hazards. Replacement procedure 1)Remove the old connector by cutting the wires at a point close to the connector. Important: Do not re-use a connector. (Discard it.) 2)Strip about 15 mm of the insulation from the ends of the wires. If the wires are stranded, twist the strands to avoid frayed conductors. 3)Align the lengths of the wires to be connected. Insert the wires fully into the connector. 4)Use a crimping tool to crimp the metal sleeve at its center. Be sure to crimp fully to the complete closure of the tool. L. When connecting or disconnecting the internal connectors, first, disconnect the AC plug from the AC outlet.
Precautions during Servicing
A. Parts identified by the ! symbol are critical for safety. Replace only with part number specified. B. In addition to safety, other parts and assemblies are specified for conformance with regulations applying to spurious radiation. These must also be replaced only with specified replacements. Examples: RF converters, RF cables, noise blocking capacitors, and noise blocking filters, etc. C. Use specified internal wiring. Note especially: 1)Wires covered with PVC tubing 2)Double insulated wires 3)High voltage leads D. Use specified insulating materials for hazardous live parts. Note especially: 1)Insulation tape 2)PVC tubing 3)Spacers 4)Insulators for transistors E. When replacing AC primary side components (transformers, power cord, etc.), wrap ends of wires securely about the terminals before soldering. F. Observe that the wires do not contact heat producing parts (heatsinks, oxide metal film resistors, fusible resistors, etc.). G. Check that replaced wires do not contact sharp edges or pointed parts. H. When a power cord has been replaced, check that 5 - 6 kg of force in any direction will not loosen it. 1-2-1
H8740SFP
Safety Check after Servicing
Examine the area surrounding the repaired location for damage or deterioration. Observe that screws, parts, and wires have been returned to their original positions. Afterwards, do the following tests and confirm the specified values to verify compliance with safety standards.
Chassis or Secondary Conductor Primary Circuit Terminals d' d
1. Clearance Distance
When replacing primary circuit components, confirm specified clearance distance (d) and (d') between soldered terminals, and between terminals and surrounding metallic parts. (See Fig. 1) Table 1 : Ratings for selected area AC Line Voltage 230 V Clearance Distance (d) (d')
Fig. 1
3mm(d) 6 mm(d')
Exposed Accessible Part
Note: This table is unofficial and for reference only. Be sure to confirm the precise values.
2. Leakage Current Test
Confirm the specified (or lower) leakage current between B (earth ground, power cord plug prongs) and externally exposed accessible parts (RF terminals, antenna terminals, video and audio input and output terminals, microphone jacks, earphone jacks, etc.) is lower than or equal to the specified value in the table below. Measuring Method (Power ON) : Insert load Z between B (earth ground, power cord plug prongs) and exposed accessible parts. Use an AC voltmeter to measure across the terminals of load Z. See Fig. 2 and the following table.
Z AC Voltmeter (High Impedance)
B
One side of Power Cord Plug Prongs
Fig. 2
Table 2: Leakage current ratings for selected areas AC Line Voltage Load Z 2k RES. Connected in parallel 50k RES. Connected in parallel Leakage Current (i) i0.7mA AC Peak i2mA DC i0.7mA AC Peak i2mA DC One side of power cord plug prongs (B) to: RF or Antenna terminals A/V Input, Output
230 V
Note: This table is unofficial and for reference only. Be sure to confirm the precise values.
1-2-2
H8740SFP
STANDARD NOTES FOR SERVICING
Circuit Board Indications
a. The output pin of the 3 pin Regulator ICs is indicated as shown.
Top View Out In Input Bottom View
How to Remove / Install Flat Pack-IC
1. Removal
With Hot-Air Flat Pack-IC Desoldering Machine:. (1) Prepare the hot-air flat pack-IC desoldering machine, then apply hot air to the Flat Pack-IC (about 5 to 6 seconds). (Fig. S-1-1)
b. For other ICs, pin 1 and every fifth pin are indicated as shown.
5 Pin 1
Fig. S-1-1
10
(2) Remove the flat pack-IC with tweezers while applying the hot air. (3) Bottom of the flat pack-IC is fixed with glue to the CBA; when removing entire flat pack-IC, first apply soldering iron to center of the flat pack-IC and heat up. Then remove (glue will be melted). (Fig. S-1-6) (4) Release the flat pack-IC from the CBA using tweezers. (Fig. S-1-6)
c. The 1st pin of every male connector is indicated as shown.
Pin 1
Caution:
Instructions for Connectors
1. When you connect or disconnect the FFC (Flexible Foil Connector) cable, be sure to first disconnect the AC cord. 2. FFC (Flexible Foil Connector) cable should be inserted parallel into the connector, not at an angle.
1. Do not supply hot air to the chip parts around the flat pack-IC for over 6 seconds because damage to the chip parts may occur. Put masking tape around the flat pack-IC to protect other parts from damage. (Fig. S-1-2) 2. The flat pack-IC on the CBA is affixed with glue, so be careful not to break or damage the foil of each pin or the solder lands under the IC when removing it.
Hot-air Flat Pack-IC Desoldering Machine CBA
FFC Cable
Connector CBA
* Be careful to avoid a short circuit.
Masking Tape Tweezers Flat Pack-IC
Fig. S-1-2
1-3-1
NOTE_1
With Soldering Iron: (1) Using desoldering braid, remove the solder from all pins of the flat pack-IC. When you use solder flux which is applied to all pins of the flat pack-IC, you can remove it easily. (Fig. S-1-3)
Flat Pack-IC Desoldering Braid
(4) Bottom of the flat pack-IC is fixed with glue to the CBA; when removing entire flat pack-IC, first apply soldering iron to center of the flat pack-IC and heat up. Then remove (glue will be melted). (Fig. S-1-6) (5) Release the flat pack-IC from the CBA using tweezers. (Fig. S-1-6) Note: When using a soldering iron, care must be taken to ensure that the flat pack-IC is not being held by glue. When the flat pack-IC is removed from the CBA, handle it gently because it may be damaged if force is applied.
Hot Air Blower
Soldering Iron
Fig. S-1-3 (2) Lift each lead of the flat pack-IC upward one by one, using a sharp pin or wire to which solder will not adhere (iron wire). When heating the pins, use a fine tip soldering iron or a hot air desoldering machine. (Fig. S-1-4)
or
Iron Wire
Soldering Iron To Solid Mounting Point
Fig. S-1-5
Sharp Pin Fine Tip Soldering Iron
Fig. S-1-4 (3) Bottom of the flat pack-IC is fixed with glue to the CBA; when removing entire flat pack-IC, first apply soldering iron to center of the flat pack-IC and heat up. Then remove (glue will be melted). (Fig. S-1-6) (4) Release the flat pack-IC from the CBA using tweezers. (Fig. S-1-6) With Iron Wire: (1) Using desoldering braid, remove the solder from all pins of the flat pack-IC. When you use solder flux which is applied to all pins of the flat pack-IC, you can remove it easily. (Fig. S-1-3) (2) Affix the wire to a workbench or solid mounting point, as shown in Fig. S-1-5. (3) While heating the pins using a fine tip soldering iron or hot air blower, pull up the wire as the solder melts so as to lift the IC leads from the CBA contact pads as shown in Fig. S-1-5
Flat Pack-IC Tweezers
CBA
Fine Tip Soldering Iron
Fig. S-1-6
1-3-2
NOTE_1
2. Installation
(1) Using desoldering braid, remove the solder from the foil of each pin of the flat pack-IC on the CBA so you can install a replacement flat pack-IC more easily. (2) The " I " mark on the flat pack-IC indicates pin 1. (See Fig. S-1-7.) Be sure this mark matches the 1 on the PCB when positioning for installation. Then presolder the four corners of the flat pack-IC. (See Fig. S-1-8.) (3) Solder all pins of the flat pack-IC. Be sure that none of the pins have solder bridges.
Example :
Instructions for Handling Semi-conductors
Electrostatic breakdown of the semi-conductors may occur due to a potential difference caused by electrostatic charge during unpacking or repair work.
1. Ground for Human Body
Be sure to wear a grounding band (1M) that is properly grounded to remove any static electricity that may be charged on the body.
2. Ground for Workbench
Be sure to place a conductive sheet or copper plate with proper grounding (1M) on the workbench or other surface, where the semi-conductors are to be placed. Because the static electricity charge on clothing will not escape through the body grounding band, be careful to avoid contacting semi-conductors with your clothing. < Incorrect >
Pin 1 of the Flat Pack-IC is indicated by a " " mark.
Fig. S-1-7
Presolder
CBA
Flat Pack-IC CBA
Fig. S-1-8
< Correct >
Grounding Band
1M
CBA
1M Conductive Sheet or Copper Plate
1-3-3
NOTE_1
PREPARATION FOR SERVICING
How to Enter the Service Mode
About Optical Sensors Caution: An optical sensor system is used for the Tape Start and End Sensors on this equipment. Carefully read and follow the instructions below. Otherwise the unit may operate erratically. What to do for preparation Insert a tape into the Deck Mechanism Assembly and press the PLAY button. The tape will be loaded into the Deck Mechanism Assembly. Make sure the power is on, TP507 (SENSOR INHIBITION) to GND. This will stop the function of Tape Start Sensor, Tape End Sensor and Reel Sensors. (If these TPs are connected before plugging in the unit, the function of the sensors will stay valid.) See Fig. 1. Note: Because the Tape End Sensors are inactive, do not run a tape all the way to the start or the end of the tape to avoid tape damage.
Q503
Q504 TP507 S-INH
Fig. 1
1-4-1
HC4C1PFS
CABINET DISASSEMBLY INSTRUCTIONS
1. Disassembly Flowchart
This flowchart indicates the disassembly steps to gain access to item(s) to be serviced. When reassembling, follow the steps in reverse order. Bend, route, and dress the cables as they were originally.
[1] Top Case [2] Front Assembly [3] VCR Chassis Unit [4] Jack CBA [5] Function CBA [6] Deck Assembly [7] Main CBA
(1): Identification (location) No. of parts in the figures (2): Name of the part (3): Figure Number for reference (4): Identification of parts to be removed, unhooked, unlocked, released, unplugged, unclamped, or desoldered. P=Spring, L=Locking Tab, S=Screw, CN=Connector *=Unhook, Unlock, Release, Unplug, or Desolder e.g. 2(S-2) = two Screws (S-2), 2(L-2) = two Locking Tabs (L-2) (5): Refer to "Reference Notes."
Reference Notes
CAUTION: Locking Tabs (L-1) and (L-2) are fragile. Be careful not to break them. 1. Release Locking Tab (L-3) and remove Screw (S-2), five Screws (S-3), three Screws (S-4) and Screw (S-5). Then, slowly lift the VCR Chassis Unit (Deck Assembly, Function CBA, Jack CBA and Main CBA) up. 2. When reassembling, solder wire jumpers as shown in Fig. 5. 3. Before installing the Deck Assembly, be sure to place the pin of LD-SW on Main CBA as shown in Fig. 6. Then, install the Deck Assembly while aligning the hole of Cam Gear with the pin of LD-SW, the shaft of Cam Gear with the hole of LD-SW as shown in Fig. 6.
2. Disassembly Method
REMOVAL ID/ LOC. No. [1] [2] PART REMOVE/*UNHOOK/ Fig. UNLOCK/RELEASE/ Note No. UNPLUG/DESOLDER 1 2 7(S-1) *3(L-1),*4(L-2) *(L-3), 5(S-3), 3(S-4), (S-5) Desolder, (S-6) Desolder 2(S-7), Desolder ----------
Top Case Front Assembly VCR Chassis Unit Jack CBA Function CBA Deck Assembly Main CBA
[3] [4] [5] [6] [7]
3 4 5 5,6 5
1 2,3 -
(1)
(2)
(3)
(4)
(5)
1-5-1
HC2C0DC
(S-1) (S-1)
(S-4) (S-3) [3]VCR Chassis Unit
(S-3) (S-5) (S-4) (S-3)
[1] Top Case
(S-1)
Fig. 1
(L-2)
(L-2)
(L-3)
Fig. 3
[4] Jack CBA (S-6)
[2] Front Assembly (L-1)
Desolder
Fig. 2
Fig. 4
1-5-2
HC2C0DC
FE Head
Cylinder Assembly Pin AC Head Assembly
SW507 LD-SW
[6] Deck Assembly
[7] Main CBA
[7] Main CBA (S-7)
[6] Deck Assembly Cam Gear Shaft Hole
[5] Function CBA Desolder from bottom From Cylinder Assembly From AC Head Assembly
Hole (S-7) LD-SW Pin [7] Main CBA
Fig. 6
From Capstan Motor Assembly Lead with white stripe
From FE Head
Lead with red stripe
Lead with white stripe
TOP VIEW Lead connections of Deck Assembly and Main CBA
Fig. 5
1-5-3
HC2C0DC
ELECTRICAL ADJUSTMENT INSTRUCTIONS
General Note: "CBA" is an abbreviation for "Circuit Board Assembly." NOTE: 1.Electrical adjustments are required after replacing circuit components and certain mechanical parts. It is important to do these adjustments only after all repairs and replacements have been completed. Also, do not attempt these adjustments unless the proper equipment is available. 2.To perform these alignment / confirmation procedures, make sure that the tracking control is set in the center position: Press either "L5? " or "K" button on the remote control unit first, then the "PLAY" button (Front Panel only).
Head Switching Position Adjustment
Purpose: To determine the Head Switching point during playback. Symptom of Misadjustment: May cause Head Switching noise or vertical jitter in the picture. Test point Adj.Point Mode PLAY (SP) Input -----
VR501 TP751(V-OUT) TP502(RF-SW) (Switching Point) (MAIN CBA) GND Tape FL6A Measurement Equipment Oscilloscope
Test Equipment Required
1.Oscilloscope: Dual-trace with 10:1 probe, V-Range: 0.001~50V/Div., F-Range: DC~AC-20MHz 2.Alignment Tape (FL6A)
Spec. 6.5H±1H (412.7µs±60µs)
Connections of Measurement Equipment
Oscilloscope Main CBA TP751 GND TP502 CH1 CH2 Trig. (+)
Figure 1
EXT. Syncronize Trigger Point V-Sync CH1 1.0H CH2 6.5H 0.5H
Switching Pulse
Reference Notes: Playback the Alignment tape and adjust VR501 so that the V-sync front edge of the CH1 video output waveform is at the 6.5H(412.7µs) delayed position from the rising edge of the CH2 head switching pulse waveform.
1-6-1
HC2C0EA
Servo/System Control Block Diagram
BLOCK DIAGRAMS
Comparison Chart of Models & Marks
Model 25A-254
MAIN CBA
SW507 LD-SW D502 S-LED AL+5V RS501 REMOTE SENSOR
(DECK ASSEMBLY)
AC HEAD ASSEMBLY
IC501 (SERVO/SYSTEM CONTROL)
14 REMOCON-IN 9 95 94 10 4 80 79
Mark A
Model 25A-654
Mark B
TP507 S-INH KEY SWITCH CL505 4 2 SW505 CH-UP KEY-1 KEY-2
FUNCTION CBA
CN651 4 2 KEY SWITCH KEY SWITCH
KEY- 1 7 KEY- 2 8
CL287 CONTROL HEAD
5 6
CTL(+) CTL(-)
CL504 5 6 TP506 END-S Q503
AL+5V
PS503 S-REEL TIMER+5V
Q501 RESET
LD-SW CTL(+) CTL(-) ST-S END-S T-REEL S-REEL
B DRV-DATA 68 DRV-STB 69 DRV-CLK 70
IC561 (FIP DRIVER)
28 DRV-DATA G1 23 2 DRV-STB G2 22 1 DRV-CLK G3 21 G4 20
FP562
LED CLOCK
Q504 ST-S
T-REEL
34 RESET
S1 7 S2 8 S7 S8 S9 S10 A AL+5V
13 14 16 17
SENSOR CBA
SW508 RESET
Q505 END-S
D561 STAND-BY
TU701(TUNER UNIT)
SENSOR CBA
TP501 CTL
97 CTL
Q562 POWER-LED 23
D562 POWER
Q502
Q563
D563 CAS
3 12 5 11
SDA SDA SCL SCL
CAS-LED 24
AL+5V VR501 SW-POINT
84 FF/REW-L 2 PG-DELAY 31 REC-SAF -SW
Q564
D564 TIMER
IC503 (MEMORY)
5 SDA 6 SCL
TIMER-LED 25
Q565
D565 REC
CYLINDER ASSEMBLY
PG SENSOR
CAPSTAN MOTOR
CAPSTAN MOTOR
M
DRUM MOTOR
M
LOADING MOTOR
M
12 11 10 9 8 7 6 5 4 3 2 1
CL502 C-F/R AL+15V/+12V AL+12V P-ON+5V GND C-FG C-CONT GND D-FG LM-FWD/REV D-CONT D-PG TO POWER SUPPLY BLOCK
AL+5V SW506 REC-SAFETY
REC-LED 26 A-MUTE-H 83
IIC-BUS SDA IIC-BUS SCL A-MUTE-H IIC-BUS SDA IIC-BUS SCL Hi-Fi-H-SW A-MODE IIC-BUS SDA IIC-BUS SCL DAVN-L D-REC-H RF-SW C-ROTA D-V SYNC H-A-SW H-A-COMP V-ENV C-SYNC DAVN-L
TO AUDIO BLOCK
78 C-F/R
AL+15V/+12V AL+12V P-ON+5V
87 C-FG 76 C-CONT 89 81 77 90
Hi-Fi-H-SW 19 A-MODE 61 IIC-BUS SDA IIC-BUS SCL DAVN-L D-FG D-REC-H LM-FWD/REV RF-SW D-CONT C-ROTA D-PG D-V SYNC B H-A-SW H-A-COMP V-ENV C-SYNC DAVN-L
72 71 20 65 18 15 13 16 17 6 58 20
TO Hi-Fi AUDIO BLOCK
TO VIDEO BLOCK
C-POW-SW P-ON-H P-DOWN-L
66 C-POW-SW 67 P-ON-H 86 P-DOWN-L
1-7-1
1-7-2
HC2C1BLS
Video Block Diagram
Comparison Chart of Models & Marks
Model 25A-254 25A-654
IC640 (VPS)
DAVN-L IIC BUS-SDA IIC BUS-SCL OSD-V-IN 14 6 7 16
REC-VIDEO SIGNAL
PB-VIDEO SIGNAL
MODE: SP/REC
Mark A B
VPS CBA
MAIN CBA
IC501 (OSD)
TO SERVO/SYSTEM CONTROL BLOCK
50
DAVN-L IIC BUS SDA IIC BUS SCL
52
OSD CHARACTER MIX
DAVN-L IIC BUS SDA IIC BUS SCL VPS-V
Q351 BUFFER
IC301 (Y/C SIGNAL PROCESS)
65
43
46
68 69
78
79
Y. DELAY
SERIAL DECORDER
CL253 V(R)-1 V-COM V(L)-1 V(L)-2 V-COM V(R)-2
(DECK ASSEMBLY)
CYLINDER ASSEMBLY
1 2 3 4 5 6
TU701 VIDEO 6 TU-VIDEO 24 B JK756 V-IN-F
48 50 52 54 56
TUNER IN1 IN2 FRT IN2 FRT PB/EE MUTE TUNER IN1 PB/EE MUTE
LUMINANCE SIGNAL PROCESS
BYPASS AGC
R
P
SP EP
SP HEAD AMP
96 95 93 94
VIDEO (R)-1 HEAD VIDEO (L)-1 HEAD VIDEO (L)-2 HEAD VIDEO (R)-2 HEAD
CHARA. INS. 1/2
CCD 1H DELAY
Y
+
C
REC FM AGC
EP HEAD AMP
90 89 88 87
B
WF2 TP502 RF-SW
CHROMINANCE SIGNAL PROCESS
R PR P
D-REC-H 80 RF-SW/C-ROTA D-V-SYNC B H-A-SW H-A-COMP V-ENV C-SYNC
70 62 71 83 84 67
JACK CBA
WF1 TP751 V-OUT
FBC
Y/C MIX
P
JK101 Q101 CL101 1 BUFFER V-OUT1 19 3 20 V-IN1 JK102 Q102 CL102 1 V-OUT2 19 BUFFER 3 20 V-IN2
CL151
V-OUT1 V-IN1 1 3 61 63
R
D-REC-H RF-SW C-ROTA D-V-SYNC H-A-SW H-A-COMP V-ENV C-SYNC
TO SERVO/SYSTEM CONTROL BLOCK
AGC
VXO
CL152
V-OUT2 V-IN2 1 3 58 59 28 29 21
X301 4.43MHz
TP301 C-PB WF5
1-7-3
1-7-4
HC2C1BLV
Audio Block Diagram (A)
Comparison Chart of Models & Marks
Model 25A-254 25A-654 Mark A B
PB-AUDIO SIGNAL JACK CBA
JK101 A-IN1(R) A-IN1(L) A-OUT1(R) A-OUT1(L)
2 6 1 3 TU701 AUDIO 2 TU-AUDIO 21
REC-AUDIO SIGNAL
Mode : SP/REC
MAIN CBA
CL101 8 6
A-IN1 A-OUT1
CL151 8 6
IC151 (SWITCHING) PB/EE PB/EE 3 PB/EE IN2 TUNER PB/EE IN1 IN1 SW CTL IC301 (AUDIO SIGNAL PROCESS) TUNER 13 IN1 15 IN2 17 PB-ON 5 6 EQ AMP SP/LP-ON +5V 7 REC-ON 8 9 INV R ATT P
JK102 A-IN2(R) A-IN2(L) A-OUT2(R) A-OUT2(L)
2 6 1 3
CL102 8 6
A-IN2 A-OUT2
CL152 8 6
Q151
BUFFER
1 5 2 4 12 14 15 11 10 9 AUDIO-SW-1 AUDIO-SW-2 TO SERVO/SYSTEM CONTROL BLOCK
Q152
BUFFER
13
ALC DET ALC LINE AMP MUTE
12 11
(DECK ASSEMBLY)
ACE HEAD ASSEMBLY
AUDIO HEAD AUDIO ERASE HEAD CN287 A-PB/REC A-COM AE-H AE-H/FE-H 4 3 1 2 4 3 1 2 CN504 A-PB/REC A-COM AE-H AE-H/FE-H Q401 Q402 BIAS OSC 1 2 Q406
AUTO BIAS
3
100
REC AMP
Q404 (PB=ON)
FE HEAD
FULL ERASE HEAD CN501 2 FE-H 1 FE-H-GND Q405 (PB=ON)
SWITCHING Q403 D-REC-OFF +5V
AUDIO HD-SW CONTROL 16
SERIAL DECODER
68 69
71 A-MUTE-H IIC-BUS SDA IIC-BUS SCL TO SERVO/SYSTEM CONTROL BLOCK
1-7-5
1-7-6
HC2C1BLA
Audio Block Diagram (B)
Comparison Chart of Models & Marks
Model 25A-254 25A-654 Mark A B
PB-AUDIO SIGNAL
REC-AUDIO SIGNAL
Mode : SP/REC
MAIN CBA
TO Hi-Fi AUDIO BLOCK
N-A-PB N-A-REC
IC301 (AUDIO SIGNAL PROCESS)
13 TUNER
15 IN1
17 IN2 ALC DET
12 LINE AMP MUTE 11
PB-ON 5 6 EQ AMP SP/LP-ON +5V 7 8 9
INV R ATT P
ALC
(DECK ASSEMBLY)
ACE HEAD ASSEMBLY
AUDIO HEAD AUDIO ERASE HEAD CL287 A-PB/REC A-COM AE-H AE-H/FE-H 4 3 1 2 4 3 1 2 CL504 A-PB/REC A-COM AE-H FE-H Q401 Q402 BIAS OSC 1 2 Q406
REC-ON
AUTO BIAS
3
100
REC AMP
Q404 (PB=ON)
FE HEAD
FULL ERASE HEAD CL501 1 FE-H 2 FE-H-GND
Q403 Q405 (PB=ON)
SWITCHING D-REC-OFF +5V
AUDIO HD-SW CONTROL 16
SERIAL DECODER
68 69
71
A-MUTE-H IIC-BUS SDA IIC-BUS SCL
TO SERVO/SYSTEM CONTROL BLOCK
1-7-7
1-7-8
HC4C1BLA
Hi-Fi Audio Block Diagram (B)
Comparison Chart of Models & Marks
Model 25A-254 25A-654 Mark A B
JACK CBA
JK101 A-IN1(R) A-IN1(L) A-OUT1(R) A-OUT1(L)
2 6 1 3
PB-AUDIO SIGNAL
REC-AUDIO SIGNAL
Mode : SP/REC
CL101 10 8 6 12 CL102 9 8 6 11
CL151
A-IN1(R) A-IN1(L) A-OUT1(R) A-OUT1(L) 10 8 6 12
MAIN CBA
JK102 A-IN2(R) A-IN2(L) A-OUT2(R) A-OUT2(L)
2 6 1 3
CL152
A-IN2(R) A-IN2(L) A-OUT2(R) A-OUT2(L) 9 8 6 11
JK751 A-OUT(R)
REAR
A-OUT(L)
TU701 AUDIO
21 TU-AUDIO 22 SIF 2 76 75
IC451 (MTS/ SAP/ Hi-Fi AUDIO PROCESS/ Hi-Fi HEAD AMP)
SW SW ALC D.C. ALC D.C. R-CH PNR P R LIM
69 73 71 51 65 47
SW NOISE
COMP
R-CH BPF
SERIAL DATA DECODER
38 39
IIC-BUS SDA IIC-BUS SCL
DEV
VCO
LPF
DO DET
ENV DET
Q451
23
A-MODE
JK758 A-IN(R)-F
R-CH INSEL
48
TO SERVO/ SYSTEM CONTROL BLOCK
OUTPUT SELECT ALC MUTE
80 2 78
FRONT
JK757 A-IN(L)-F
67 7 11 9 53
HOLD PULSE L-CH INSEL
13 14
40
Hi-Fi-H-SW
NOISE DET LIM DEV VCO
MIX
COMP
26
CN701 CN1 CN1 CN701 2 SIF 2 4 TU-AUDIO(R) 4 IF SINAL PROCESS 1 TU-AUDIO 1 5 TU-AUDIO(L) 5
AFV CBA
LPF
CL253 Hi-Fi-A(R) Hi-Fi-COM Hi-Fi-A(L)
NOR SW
L-CH PNR
R P SW NOISE R COMP L-CH BPF LIM
31 30 24 27 7 8 9
CYLINDER ASSEMBLY
Hi-Fi AUDIO (R) HEAD Hi-Fi AUDIO (L) HEAD
L
TO AUDIO BLOCK
N-A-REC N-A-PB
6 4
1-7-9
1-7-10
HC4C1BLH
Power Supply Block Diagram
NOTE : The voltage for parts in hot circuit is measured using hot GND as a common terminal. CAUTION FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH THE SAME TYPE T1.6AL/250V FUSE. CAUTION ! Fixed voltage (or Auto voltage selectable ) power supply circuit is used in this unit. If Main Fuse (F001) is blown, check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power supply. Otherwise it may cause some components in the power supply circuit to fail.
Comparison Chart of Models & Marks
Model 25A-254 25A-654 Mark A B
MAIN CBA
HOT CIRCUIT. BE CAREFUL.
A F001 T1.6A L 250V AC001 L003 LINE FILTER D001 - D004 BRIDGE RECTIFIER
2
B
T001 Q051
12
Q052
13
Q053
Q057
4 14
Q058 Q001
15
P-ON+44V P-ON-H AL+15V/+12V AL+9V AL+12V C-POW-SW AL+5V TIMER+5V P-ON+5V P-DOWN-L AL-5V Q054
16
Q002
11
7
17
6
18
Q056 IC001 ERROR VOLTAGE DET
4 1
Q003
HOT
3
2
Q004 (SHUNT REGULATOR)
REG
COLD
1-7-11
1-7-12
HC2C1BLP
FUNCTION INDICATOR SYMBOLS
Note: The following symbols will appear on the indicator panel to indicate the current mode or operation of the VCR. On-screen modes will also be momentarily displayed on the tv screen when you press the operation buttons.
[ 25A-254 ] Display panel
STANDBY
FUNCTION
TAPE IN
TIMER
REC
" H "= LED Light on, " L "= LED Light off Led Mode STANDBY FUNCTION TAPE IN 1. When reel and capstan mechanism is not functioning correctly 2. When tape loading mechanism is not functioning correctly 3. When cassette loading mechanism is not functioning correctly 4. When the drum is not working properly TIMER Power on = " H " Power off = " L " VCR mode = " H " TV mode = " L " Cassette in = " H " Cassette out = " L " Cassette in Cassette in Cassette in Cassette in Timer stand by = " H " One touch recording = " H " Timer recording = " H " General mode = " L " REC mode = " H " REC pause General mode = " L " Blinks at 0.8Hz interval Indicator Active
Blinks at 0.8Hz interval Blinks at 1.6Hz interval Blinks at 3.2Hz interval Blinks at 6.4Hz interval
REC
1-7-13
HC4C1FIS
[ 25A-654 ] Display panel
" H "= LED Light on, " L "= LED Light off LED MODE CASSETTE "IN" CASSETTE "OUT" CLOCK POWER ON REC REC PAUSE T-REC,OTR " " " 88:88 " PWR." " REC " " REC " " " " " INDICATOR ACTIVE ON OFF ON ON ON Blinks at 0.8Hz interval ON (T-REC OFF,T-REC incomplete Blinks at 0.8Hz interval) Blinks at 0.8Hz interval Blinks at 0.8Hz interval Blinks at 0.8Hz interval Blinks at 0.8Hz interval Blinks at 0.8Hz interval Blinks at 0.8Hz interval
When reel and capstan mechanism is not functioning correctly When tape loading mechanism is not functioning correctly When cassette loading mechanism is not functioning correctly When the drum is not working properly P-ON Power safety detection S-INH condition
" " " " " " " " " "
1 2 3 4 5
" " " " " " " " " "
All modes
1-7-14
HC4C1FIS
SCHEMATIC DIAGRAMS / CBA'S AND TEST POINTS
Standard Notes WARNING
Many electrical and mechanical parts in this chassis have special characteristics. These characteristics often pass unnoticed and the protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts that have these special safety characteristics are identified in this manual and its supplements; electrical components having such features are identified by the mark " ! " in the schematic diagram and the parts list. Before replacing any of these components, read the parts list in this manual carefully. The use of substitute replacement parts that do not have the same safety characteristics as specified in the parts list may create shock, fire, or other hazards.
Notes:
1. Do not use the part number shown on these drawings for ordering. The correct part number is shown in the parts list, and may be slightly different or amended since these drawings were prepared. 2. All resistance values are indicated in ohms (K=103, M=106). 3. Resistor wattages are 1/4W or 1/6W unless otherwise specified. 4. All capacitance values are indicated in µF (P=10-6 µF). 5. All voltages are DC voltages unless otherwise specified. 6. Electrical parts such as capacitors, connectors, diodes, IC's, transistors, resistors, switches, and fuses are identified by four digits. The first two digits are not shown for each component. In each block of the diagram, there is a note such as shown below to indicate these abbreviated two digits.
Capacitor Temperature Markings
Mark (B) (F) (SR) (Z) Capacity change rate Standard temperature 20°C 20°C 20°C 20°C Temperature range -25~+85°C -25~+85°C -25~+85°C -10~+70°C
±10%
+30 - 80%
±15%
+30 - 80%
Capacitors and transistors are represented by the following symbols.
CBA Symbols
(Top View) (Bottom View) + Electrolytic Capacitor
Schematic Diagram Symbols
Digital Transistor
(Bottom View)
Transistor or Digital Transistor
E C B (Top View)
(Top View)
NPN Transistor
ECB ECB
PNP Transistor
(Top View)
(Top View)
NPN Digital Transistor
ECB ECB
PNP Digital Transistor
1-8-1
SCPA1
LIST OF CAUTION, NOTES, AND SYMBOLS USED IN THE SCHEMATIC DIAGRAMS ON THE FOLLOWING PAGES: 1. CAUTION: FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH THE SAME TYPE FUSE. 2. CAUTION: Fixed Voltage (or Auto voltage selectable) power supply circuit is used in this unit. If Main Fuse (F001) is blown, first check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power supply. Otherwise it may cause some components in the power supply circuit to fail. 3. Note: (1) Do not use the part number shown on the drawings for ordering. The correct part number is shown in the parts list, and may be slightly different or amended since the drawings were prepared. (2) To maintain original function and reliability of repaired units, use only original replacement parts which are listed with their part numbers in the parts list section of the service manual. 4. Wire Connectors (1) Prefix symbol "CN" means "connector" (can disconnect and reconnect). (2) Prefix symbol "CL" means "wire-solder holes of the PCB" (wire is soldered directly). 5. Mode: SP/REC 6. Voltage indications for PLAY and REC modes on the schematics are as shown below:
Unit: Volts
1 5.0
2
3 5.0 (2.5)
PLAY mode REC mode
The same voltage for both PLAY & REC modes
Indicates that the voltage is not consistent here.
7. How to read converged lines
1-D3 Distinction Area Line Number (1 to 3 digits) Examples: 1. "1-D3" means that line number "1" goes to area "D3". 2. "1-B1" means that line number "1" goes to area "B1".
3 AREA D3 2 1 A
1-B1
AREA B1 1-D3 B C D
8. Test Point Information
: Indicates a test point with a jumper wire across a hole in the PCB. : Used to indicate a test point with a component lead on foil side. : Used to indicate a test point with no test pin. : Used to indicate a test point with a test pin.
1-8-2
SCRK05
Main 1/5 Schematic Diagram
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
1-8-3
1-8-4
1-8-5
HC2C1SCM1
Main 2/5 Schematic Diagram
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
1-8-6
1-8-7
1-8-8
HC2C1SCM2
Main 3/5 Schematic Diagram
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
1-8-9
1-8-10
1-8-11
HC2C1SCM3
Main 4/5 Schematic Diagram
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
NOTE : THE VOLTAGE FOR PARTS IN HOT CIRCUIT IS MEASURED USING HOT GND AS A COMMON TERMINAL.
CAUTION FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH THE SAME TYPE FUSE.
CAUTION ! Fixed voltage (or Auto voltage selectable ) power supply circuit is used in this unit. If Main Fuse (F001) is blown, check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power supply. Otherwise it may cause some components in the power supply circuit to fail.
1-8-12
1-8-13
1-8-14
HC2C1SCM4
Main 5/5 Schematic Diagram ( B )
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
1-8-15
1-8-16
HC4C1SCM5
VPS Schematic Diagram
1-8-17
1-8-18
HC2C1SCV
Function Schematic Diagram
1-8-19
1-8-20
HC2C1SCF
AFV Schematic Diagram ( B )
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
1-8-21
1-8-22
HC4C1SCAFV
Jack Schematic Diagram
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
1-8-23
1-8-24
HC2C1SCJ
Function CBA Top View
Function CBA Bottom View
BHC400F01019-B
1-8-25
1-8-26
AFV CBA Top View ( B )
AFV CBA Bottom View ( B )
Comparison Chart of Models and Marks
MODEL 25A-254 25A-654 MARK A B
BHC400F01091
VPS CBA Top View
VPS CBA Bottom View
BHC400F01019-C
1-8-27
1-8-28
Jack CBA Top View
Jack CBA Bottom View
BHC400F01019-E
1-8-29
1-8-30
Main CBA Top View
BECAUSE A HOT CHASSIS GROUND IS PRESENT IN THE POWER SUPPLY CIRCUIT , AN ISOLATION TRANSFORMER MUST BE USED. ALSO , IN ORDER TO HAVE THE ABILITY TO INCREASE THE INPUT SLOWLY , WHEN TROUBLESHOOTING THIS TYPE POWER SUPPLY CIRCUIT , A VARIABLE ISOLATION TRANSFORMER IS REQUIRED.
CAUTION FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH THE SAME TYPE FUSE.
CAUTION ! Fixed voltage power supply circuit is used in this unit. If Main Fuse (F001) is blown, check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power supply. Otherwise it may cause some components in the power supply circuit to fail.
NOTE : The voltage for parts in hot circuit is measured using hot GND as a common terminal.
Sensor CBA Top View
BHB300F01014-A
BHB300F01014-B
WF1 TP751 V-OUT
TP506 END-S
WF2 TP502 RF-SW
TP507 S-INH
VR501 SW-P
TP501 CTL
WF5 TP301 C-PB
1-8-31
1-8-32
1-8-33
BHC400F01019-A
Main CBA Bottom View
BECAUSE A HOT CHASSIS GROUND IS PRESENT IN THE POWER SUPPLY CIRCUIT , AN ISOLATION TRANSFORMER MUST BE USED. ALSO , IN ORDER TO HAVE THE ABILITY TO INCREASE THE INPUT SLOWLY , WHEN TROUBLESHOOTING THIS TYPE POWER SUPPLY CIRCUIT , A VARIABLE ISOLATION TRANSFORMER IS REQUIRED.
CAUTION FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH THE SAME TYPE FUSE.
CAUTION ! Fixed voltage power supply circuit is used in this unit. If Main Fuse (F001) is blown, check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power supply. Otherwise it may cause some components in the power supply circuit to fail.
NOTE : The voltage for parts in hot circuit is measured using hot GND as a common terminal.
1-8-34
1-8-35
1-8-36
BHC400F01019-A
Waveforms
WF1
(TP751 of Main CBA)
V-OUT E-E 10usec
50mV x 10
WF1 UPPER
(TP751 of Main CBA) of Main CBA)
WF2 LOWER (TP302
V-OUT RF-SW
0.1V x 10 0.5V x 10 50usec
WF5 UPPER
(TP301 of Main CBA) of Main CBA)
WF2 LOWER (TP302
C-PB RF-SW
10mV x 10 0.5V x 10 5msec
1-9-1
U25WFPAL
Comparison Chart of Models & Marks
Model 25A-254 25A-654 Mark A B
SENSOR CBA (BHB300F01014)
WIRING DIAGRAM
B VIDEO IN FRONT AUDIO IN (R) AUDIO IN (L) REAR AUDIO OUT (R) AUDIO OUT (L) ANT-IN ANT-OUT CN701 1 2 3 4 5 6 7 8 9 CN1 1 2 3 4 5 6 7 8 9 AC CORD B
(DECK ASSEMBLY)
AC HEAD ASSEMBLY
AUDIO ERASE HEAD AUDIO HEAD CONTROL HEAD
SENSOR CBA (BHB300F01014)
CL287 AE-H AE-H/FE-H A-COM A-PB/REC CTL(+) CTL(-) 1 2 3 4 5 6 1 2 3 4 5 6 CL504 AE-H AE-H/FE-H A-COM A-PB/REC CTL(+) CTL(-)
TU-AUDIO SIF GND TU-AUDIO(R) TU-AUDIO(L) P-ON+5V P-ON+5V IIC BUS-SCL IIC BUS-SDA
AFV CBA (BHC400F01091)
FE HEAD
FULL ERASE HEAD
CL501 2 FE-H 1 FE-H GND
LOADING MOTOR
M
CAPSTAN MOTOR
M
CAPSTAN MOTOR
CYLINDER ASSEMBLY
PG SENSOR
DRUM MOTOR
M
12 11 10 9 8 7 6 5 4 3 2 1
CL502 C-F/R AL+15V/+12V AL+12V P-ON+5V GND C-FG C-CONT GND D-FG LM-FWD/REV D-CONT D-PG
MAIN CBA (BHC400F01019A)
CL151 1 2 3 4 5 6 7 8 9 10 11 12 CL152 1 2 3 4 5 6 7 8 9 10 11
V-OUT1 GND V-IN1 AL+12V NU A-OUT1(R) JK1-8P-OUT A-IN1(L) NU A-IN1(R) GND A-OUT1(L) V-OUT2 GND V-IN2 NU GND A-OUT2(R) SC2-IN A-IN2(L) A-IN2(R) GND A-OUT2(L)
CL101 1 2 3 4 5 6 7 8 9 10 11 12 CL102 1 2 3 4 5 6 7 8 9 10 11
JK101,102
1 3 5 7 9 2 4 6 8 10 12 14 16 18 20
JACK CBA (BHC400F01019E)
11 13 15 17 19 21
VIDEO (R)1 HEAD VIDEO (L)1 HEAD VIDEO (L)2 HEAD VIDEO (R)2 HEAD Hi-Fi AUDIO (R) HEAD Hi-Fi AUDIO (L) HEAD 1 2 3 4 5 6 7 8 9 CL253 V(R)-1 V-COM V(L)-1 V(L)-2 V-COM V(R)-2 Hi-Fi-A(R) Hi-Fi-COM Hi-Fi-A(L)
B
IIC BUS-SCL DAVN-L OSD-V-IN P-ON+5V IIC BUS-SDA FSC-IN(4.43MHz) TUN-SW2
VPS CBA (BHC400F01019C)
CL505 1 KEY2 2 GND 3 KEY1
CN651 1 2 3
FUNCTION CBA (BHC400F01019B)
1-10-1
1-10-2
HC2C1WI
IC PIN FUNCTION DESCRIPTIONS
Comparison Chart of Models and Marks
Model 25A-254 25A-654 Mark A B A IN N.U. H-ACOMP 17 16 Pin IN/ Mark No. OUT A B Signal Name N.U. Function Not Used Video Head Amp Switching Pulse Not Used Head Amp Comparator Signal Video Head Switching Pulse Not Used HiFi Audio Head Switching Pulse VPS/PDC Data Receive = "L" Not Used Tuner System Control Signal Output "STANDBY" LED Signal Output Not Used Active Level H/L H/L H/L H/L L H/L H/L H/L H/L H/L -
OUT H-A-SW
IC501( SERVO / SYSTEM CONTROL IC )
Pin IN/ Mark No. OUT 1 IN Signal Name SC2-IN "H" 4.5V, "L" 1.0V Active Function Level Input Signal from L/Hi-z Pin 8 of SCART2 Video Head Switching Pulse Signal Adjusted Voltage P-ON Power Detection Input Signal Tape End Position Detect Signal Automatic Frequency Control Signal Video Envelope Comparator Signal Key Scan Input Signal 1 Key Scan Input Signal 2 Deck Mode Position Detector Signal Tape Start Position Detector Signal Not Used Not Used Dummy V-sync Output Remote Control Sensor Color Phase Rotary Changeover SIgnal A/D
B
18 A 19 B
OUT RF-SW N.U.
OUT HiFi-HSW IN DAVN-L N.U.
2
IN
PGDELAY POWSAF END-S
20 21 A/D 22 A B A/D 24 A B A/D A/D 26 A/D 27 A/D 28 25 A B A B
3
IN
TUNOUT SW2 OUT POWER LED N.U.
4
IN
A/D
23
5
IN
AFC
OUT CAS LED "TAPE IN" LED Signal Output OUT N.U. TIMER LED N.U. Not Used "TIMER" LED Signal Output Not Used
6 7 8 9
IN IN IN IN
V-ENV KEY-1 KEY-2 LD-SW
"REC" LED SigOUT REC LED nal Output N.U. N.U. N.U. Not Used Not Used Not Used Audio Input/ Output Switching Control Signal 1 (Mono) Not Used Audio Input/ Output Switching Control Signal 2 (Mono) Not Used
10 11 12 13 14
OUT ST-S N.U. N.U.
A/D 29 H/Hi-z L 30
A
AUDIOOUT SW1 N.U.
Z/L
B
-
OUT D-VSYNC IN REMOC ON-IN
A
AUDIOOUT SW2 N.U.
Z/L
B H/L
-
15
OUT C-ROTA
1-11-1
HC4C1PIN
Pin IN/ Mark No. OUT
Signal Name
Function Recording Safety SW Detect (With Record tab="L"/ With out Record tab="H") Not Used Not Used System Reset Signal (Reset="L") Sub Clock Sub Clock Vcc Main Clock Input Main Clock Input Vss(GND) Not Used Not Used Clock Select (GND) Clock Input for letter size Clock Output for letter size Not Used LP
Active Level
Pin IN/ Mark No. OUT A 61 IN -
Signal Name N.U.
Function Not Used
Active Level L L L/Hi-z H H/L H/L H/L H/L H/L PWM PWM
31
IN
RECSAF
H 62 L L 69 68 66 67 63 64 65
B
Hi-Fi Tape A-MODE Detection Signal N.U. N.U. N.U. Not Used Not Used Not Used
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58
IN IN IN IN IN
N.U. N.U. RESET XC-IN Vcc X-IN Vss N.U. N.U. CLKSEL OSCIN
OUT D-REC-H Delayed Record Signal COUT POWER- Capstan Power Switching Pulse SW IN A B A B A P-ON-H N.U. Power On Signal at High Not Used LED Clock Driver IC Control Data Not Used
OUT XC-OUT
OUT X-OUT
OUT DRVDATA N.U.
LED Clock OUT DRV-STB Driver IC Chip Select Signal N.U. Not Used LED Clock OUT DRV-CLK Driver IC Control Clock
2 2 OUT I C BUS- I C BUS Control SCL Clock
PULSE
70
B
OUT OSCOUT IN IN N.U. LP
71 72 73 74 75 76 77
FSC-IN 4.43MHz Clock [4.43MHz] Input OSDVss VIDEOIN N.U. OSDVss Video Signal Input Not Used Video Signal Output OSDVcc LPF Connected Terminal (Slicer) Not Used Not Used Not Used Composite Synchronized Pulse
IN/ I2C BUS- I2C BUS Control OUT SDA Data N.U. N.U. N.U. Not Used Not Used Not Used
OUT VIDEOOUT IN OSDVcc HLF N.U. N.U. N.U. C-SYNC
OUT C-CONT Capstan Motor Control Signal OUT D-CONT Drum Motor Control Signal Capstan Motor FWD/REV Control Signal (FWD="L"/ REV="H") Supply Reel Rotation Signal Take Up Reel Rotation Signal
78
OUT C-F/R
H/L
79 80 81
IN IN
S-REEL T-REEL
PULSE PULSE H/L/ Hi-z -
59 60
SCART 1 8Pin OUT 8POUT-1 Output Control Signal N.U. Not Used
OUT LM-FWD/ Loading Motor REV Control Signal N.U. Not Used
H/L -
82
1-11-2
HC4C1PIN
IN/ Pin Mark OUT No. 83
Signal Name
Function
Active Level H
Audio Mute OUT A-MUTE- Control H Signal (Mute = "H") CTL Amp Gain OUT FF/REW- Switching Signal L (FF/REW="L") IN N.U. Not Used Power Voltage PDown Detector DOWN-L Signal C-FG AMPVss D-FG D-PG N.U. Capstan Motor Rotation Detection Pulse AMPVss (GND)
84 85 86
L L
87 88 89 90 91 92 93 94
IN IN IN -
PULSE -
Drum Motor PULSE Rotation Detection Pulse Drum Motor PULSE Pulse Generator Not Used H/L
AMPVRE V-Ref for CTL AMP FIN C C Terminal Playback/ Record Control Signal (-) Playback/ Record Control Signal (+) CTL AMP Connected Terminal
OUT CTL (-)
95
OUT CTL (+)
H/L
96
-
AMPC
-
97 98 99 100
-
To Monitor for CTLAMP CTL AMP out Output AMPVcc AVcc N.U. AMPVcc A/D Converter Power Input/ Standard Voltage Input Not Used
PULSE -
Notes: Abbreviation for Active Level: PWM -----Pulse Wide Modulation A/D--------Analog - Digital Converter
1-11-3
HC4C1PIN
LEAD IDENTIFICATIONS
BN1F4M-T BA1F4M-T KTA1266(GR) KTC3199(Y,GR,BL) 2SC2785(J.H.F.K) KRA103M KRC103M KRA104M 2SD1246(S,T) BN1L4M-T KRA104M KTA1281(Y) E C B BR24C02F-W AT24C02N-10SC M24C02-MN6T CAT24WC02JI A 8 5 K 1 4 E E C B 80 LTV-817(B.C)-F EL817(A,B,C) 81 2SC1815-Y(TPE2) 2SC1815-GR(TPE2) 2SC3266-Y (TPE2) 2SC2120-Y(TPE2) KTC3203(Y) 2SC1815-BL(TPE2) 2SA1020(Y) 2SB892(S) KTC3205(Y) 2SA1015-GR(TPE2) PT-6958-FN-TP 28 15
1
14
LA71750AM-MTB QSZAB0RMB111 51 50
C
100 1 30
31
MSP3407G-QG-B8 MSP3417G-QG-B8 33 34 23 22 61 60
LA72646M-A-MPB 41
40
44 1 PT204-6B-12 MID-32A22 11
12
80
21 1 20
FS1KM-18A FS1KM-14A 16
TC4052BF(EL) BU4052BCF-E2 CD4052BCSJX 9
1
8
C E
G D S
Note: A: Anode K: Cathode E: Emitter C: Collector B: Base R: Reference S: Source G: Gate D: Drain
1-12-1
HC4C1LE
DECK MECHANISM SECTION
VIDEO CASSETTE RECORDER 25A-254/25A-654
Sec. 2: Deck Mechanism Section
I Standard Maintenance I Alignment for Mechanism I Disassembly/Assembly of Mechanism I Alignment Procedures of Mechanism
TABLE OF CONTENTS
Standard Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1-1 Service Fixtures and Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2-1 Mechanical Alignment Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3-1 Disassembly / Assembly Procedures of Deck Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4-1 Alignment Procedures of Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4-9
STANDARD MAINTENANCE
Service Schedule of Components
H: Hours Deck Ref.No. B2 B3 B8 B27 B31 B573,B574 B37 B52 *B73 B133 B410 B414 B416 B525 Part Name Cylinder Assembly Loading Motor Assembly Pulley Assembly Tension Lever Sub Assembly AC Head Assembly Reel S, Reel T Capstan Motor Cap Belt FE Head Idler Assembly Pinch Arm (A) Assembly M Brake S Assembly M Brake T Assembly LDG Belt I I I I I I I I I I I I I I I I I I I 1,000 H : Check I: Change
Periodic Service Schedule 2,000 H I I I I 3,000 H 4,000 H I
Notes: 1.Clean all parts for the tape transport (Upper Drum with Video Head / Pinch Roller / Audio Control Head / Full Erase Head) using 90% lsopropyl Alcohol. 2.After cleaning the parts, do all DECK ADJUSTMENTS. 3.For the reference numbers listed above, refer to Deck Exploded Views. * B73 ------ Recording Model only
2-1-1
U25MEN
Cleaning
Cleaning of Video Head
Clean the head with a head cleaning stick or chamois cloth. Procedure 1.Remove the top cabinet. 2.Put on a glove (thin type) to avoid touching the upper and lower drum with your bare hand. 3.Put a few drops of 90% Isopropyl alcohol on the head cleaning stick or on the chamois cloth and, by slightly pressing it against the head tip, turn the upper drum to the right and to the left. Notes: 1.The video head surface is made of very hard material, but since it is very thin, avoid cleaning it vertically. 2.Wait for the cleaned part to dry thoroughly before operating the unit. 3.Do not reuse a stained head cleaning stick or a stained chamois cloth.
Cleaning of Audio Control Head
Clean the head with a cotton swab. Procedure 1.Remove the top cabinet. 2.Dip the cotton swab in 90% isopropyl alcohol and clean the audio control head. Be careful not to damage the upper drum and other tape running parts. Notes: 1.Avoid cleaning the audio control head vertically. 2.Wait for the cleaned part to dry thoroughly before operating the unit or damage may occur.
A/C Head
Upper Cylinder Do Not !
Video Head
Cleaning Stick
2-1-2
U25MEN
SERVICE FIXTURE AND TOOLS
J-1-1, J-1-2
J-2
J-3
J-4
J-5
Ref. No. Name J-1-1 J-1-2 Alignment Tape Alignment Tape
Part No. FL6A FL6N8 (1 speed only) FL6NS8 (2 speed only) Available Locally Available Locally Available Locally Available Locally
Adjustment Head Adjustment of Audio Control Head Azimuth and X Value Adjustment of Audio Control Head / Adjustment of Envelope Waveform
J-2 J-3 J-4 J-5
Guide Roller Adj.Screwdriver Mirror Azimuth Adj.Screwdriver + X Value Adj.Screwdriver -
Guide Roller Tape Transportation Check A/C Head Height X Value
2-2-1
U25PFIX
MECHANICAL ALIGNMENT PROCEDURES
Explanation of alignment for the tape to correctly run starts on the next page. Refer to the information below on this page if a tape gets stuck, for example, in the mechanism due to some electrical trouble of the unit. B. Method to place the Cassette Holder in the tapeloaded position without a cassette tape 1. Disconnect the AC Plug. 2. Remove the Top Case and Front Assembly. 3. Turn the LDG Belt in the appropriate direction shown in Fig. M1. Release the locking tabs shown in Fig. M1 and continue turning the LDG Belt until the Cassette Holder comes to the tape-loaded position. Allow a minute or two to complete this task.
Service Information
A. Method for Manual Tape Loading/Unloading To load a cassette tape manually: 1. Disconnect the AC plug. 2. Remove the Top Case and Front Assembly. 3. Insert a cassette tape. Though the tape will not be automatically loaded, make sure that the cassette tape is all the way in at the inlet of the Cassette Holder. To confirm this, lightly push the cassette tape further in and see if the tape comes back out, by a spring motion, just as much as you have pushed in. 4. Turn the LDG Belt in the appropriate direction shown in Fig. M1 for a minute or two to complete this task. To unload a cassette tape manually: 1. Disconnect the AC plug. 2. Remove the Top Case and Front Assembly. 3. Make sure that the Moving guide preparations are in the Eject Position. 4. Turn the LDG Belt in the appropriate direction shown in Fig. M1 until the Moving guide preparations come to the Eject Position. Stop turning when the preparations begin clicking or can not be moved further. However, the tape will be left wound around the cylinder. 5. Turn the LDG Belt in the appropriate direction continuously, and the cassette tape will be ejected. Allow a minute or two to complete this task.
Top View
Moving guide T preparation (Eject Position) Moving guide S preparation (Eject Position) LOAD UNLOAD /EJECT Side View
LDG Belt
Push the tape to load it. Push the locking tab gently to unlock when loading without a cassette.
Fig. M1
Bottom View
LDG Belt (B)
UNLOAD /EJECT
Cam Gear
Fig. M2
2-3-1
U25PALMA
1.Tape Interchangeability Alignment
Note: To do these alignment procedures, make sure that the Tracking Control Circuit is set to the center position every time a tape is loaded or unloaded. (Refer to page 2-3-4, procedure 1-C, step 2.) Equipment required: Dual Trace Oscilloscope VHS Alignment Tape (FL6N8) Guide Roller Adj. Screwdriver X-Value Adj. Screwdriver Note: Before starting this Mechanical Alignment, do all Electrical Adjustment procedures.
Flowchart of Alignment for tape traveling Loading (Use a blank tape.)
Adjust the height of the Guide Rollers (Supply side and take-up side). (Use a blank tape.) (pg. 2-3-3) 1-A Check to see that the tape is not creasing and that there is no slack on the supply and take-up side Guide Rollers. (Use a blank tape.) 1-A Adjust the X Value for maximum envelope. (pg. 2-3-3) (Use Alignment Tape.) 1-B
Not good
Adjust the envelope. (pg. 2-3-4)
1-C
Not good
Check the envelope. OK Adjust the Audio Section. (Azimuth Alignment) (pg. 2-3-4) Check the audio output. OK Check the following: 1. X Value (pg. 2-3-3) 2. Envelope (pg. 2-3-4) OK
1-C
Do the final tape-traveling test to see that the tape runs normally in play mode without creasing or slacking. 1-A OK
1-D
Not good
Completion
1-D
Not good
Adjust the X value and envelope. 1-B, 1-C
1-B, 1-C
2-3-2
U25PALMA
1-A. Preliminary/Final Checking and Alignment of Tape Path
Purpose: To make sure that the tape path is well stabilized. Symptom of Misalignment: If the tape path is unstable, the tape will be damaged. Note: Do not use an Alignment Tape for this procedure. If the unit is not correctly aligned, the tape may be damaged. 1. Playback a blank cassette tape and check to see that the tape runs without creasing at Guide Rollers [2] and [3], and at points A and B on the lead surface. (Refer to Fig M3 and M4.) 2. If creasing is apparent, align the height of the guide rollers by turning the top of Guide Rollers [2] and [3] with a Guide Roller Adj. Screwdriver. (Refer to Fig. M3 and M5.)
Guide Roller [2] Guide Roller [3]
3. Check to see that the tape runs without creasing at Take-up Guide Post [4] or without snaking between Guide Roller [3] and AC Head. (Fig. M3 and M5) 4. If creasing or snaking is apparent, adjust the Tilt Adj. Screw of the AC Head. (Fig. M6)
Azimuth Adj. Screw
AC Head X-Value Adj. Screwdriver
Tilt Adj. Screw
Fig. M6
1-B. X Value Alignment
Purpose: To align the Horizontal Position of the Audio/Control/ Erase Head. Symptom of Misalignment: If the Horizontal Position of the Audio/Control/Erase Head is not properly aligned, maximum envelope cannot be obtained at the Neutral position of the Tracking Control Circuit. 1. Connect the oscilloscope to TP301 (C-PB) and TP501 (CTL) on the Main CBA. Use TP502 (RFSW) as a trigger. 2. Playback the Gray Scale of the Alignment Tape (FL6N8) and confirm that the PB FM signal is present. 3. Set the Tracking Control Circuit to the center position by pressing CH UP button then " PLAY " button on the unit. (Refer to note on bottom of page 2-3-4.)
Lead Surface of Cylinder Tape
AC Head
A
B Take-up Guide Post [4]
Fig. M3
Fig. M4
4. Use the X-Value Adj. Screwdriver so that the PB FM signal at TP301 (C-PB) is maximum. (Fig. M6) 5. Press CH UP button on the unit until the CTL waveform has shifted by approx. +2msec. Make sure that the envelope is simply attenuated (shrinks in height) during this process so that you will know the envelope has been at its peak.
Correct
Guide Roller Tape
Incorrect
Take-up Guide Post Tape
Fig. M5 2-3-3 U25PALMA
6. Press CH DOWN button on the unit until the CTL waveform has shifted from its original position (not the position achieved in step 5, but the position of CTL waveform in step 4) by approximately -2msec. Make sure that the envelope is simply attenuated (shrinks in height) once CTL waveform passes its original position and is further brought in the minus direction. 7. Set the Tracking Control Circuit to the center position by pressing CH UP button and then " PLAY " button.
1-D. Azimuth Alignment of Audio/Control/ Erase Head
Purpose: To correct the Azimuth alignment so that the Audio/ Control/Erase Head meets tape tracks properly. Symptom of Misalignment: If the position of the Audio/Control/Erase Head is not properly aligned, the Audio S/N Ratio or Frequency Response will be poor. 1. Connect the oscilloscope to the audio output jack on the rear side of the deck. 2. Playback the alignment tape (FL6N8) and confirm that the audio signal output level is 8kHz. 3. Adjust Azimuth Adj. Screw so that the output level on the AC Voltmeter or the waveform on the oscilloscope is at maximum. (Fig. M6) Dropping envelope level at the beginning of track.
1-C. Checking/Adjustment of Envelope Waveform
Purpose: To achieve a satisfactory picture and precise tracking. Symptom of Misalignment: If the envelope output is poor, noise will appear in the picture. The tracking will then lose precision and the playback picture will be distorted by any slight variation of the Tracking Control Circuit. 1. Connect the oscilloscope to TP301 (C-PB) on the Main CBA. Use TP502 (RF-SW) as a trigger. 2. Playback the Gray Scale on the Alignment Tape (FL6N8). Set the Tracking Control Circuit to the center position by pressing CH UP button and then " PLAY " button on the unit. Adjust the height of Guide Rollers [2] and [3] (Fig. M3, Page 2-3-3) watching the oscilloscope display so that the envelope becomes as flat as possible. To do this adjustment, turn the top of the Guide Roller with the Guide Roller Adj. Screwdriver. 3. If the envelope is as shown in Fig. M7, adjust the height of Guide Roller [2] (Refer to Fig. M3) so that the waveform looks like the one shown in Fig. M9. 4. If the envelope is as shown in Fig. M8, adjust the height of Guide Roller [3] (Refer to Fig. M3) so that the waveform looks like the one shown in Fig. M9. 5. When Guide Rollers [2] and [3] (Refer to Fig.M3) are aligned properly, there is no envelope drop either at the beginning or end of track as shown in Fig. M9. Note: Upon completion of the adjustment of Guide Rollers [2] and [3] (Refer to Fig. M3), check the X Value by pushing the CH UP or DOWN buttons alternately, to check the symmetry of the envelope. Check the number of pushes to ensure center position. The number of pushes CH UP button to achieve 1/2 level of envelope should match the number of pushes CH DOWN button from center. If required, redo the "X Value Alignment."
Fig. M7 Dropping envelope level at the end of track.
Fig. M8 Envelope is adjusted properly. (No envelope drop)
Fig. M9
2-3-4
U25PALMA
DISASSEMBLY/ASSEMBLY PROCEDURES OF DECK MECHANISM
Before following the procedures described below, be sure to remove the deck assembly from the cabinet. (Refer to CABINET DISASSEMBLY INSTRUCTIONS on page 1-5-1.) All the following procedures, including those for adjustment and replacement of parts, should be done in Eject mode; see the positions of [45] and [46] in Fig.DM1 on page 2-4-3. When reassembling, follow the steps in reverse order. STEP START/LOC. ING No. No. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [1] [1] [2] [2] [4] [2] [7] [8] [9] [2] [10] [11] [12] [14] [15] [2] [16] [16] [7],[10] [20] [20] [22] [22] [24] REMOVAL REMOVE/*UNHOOK/ UNLOCK/RELEASE/ UNPLUG/DESOLDER 2(S-1) (S-2) (S-3) (S-4),*(P-1) Desolder, 3(S-5) Desolder, LDG Belt, 2(S-6) (S-7) *(P-2) *(L-1),*(L-2) *(P-3) (S-9) (S-10) (S-11),*(L-3) INSTALLATION ADJUSTMENT CONDITION
PART Guide Holder A Cassette Holder Assembly Slider L Slider R Lock Lever C Plate Cylinder Assembly Loading Motor Assembly AC Head Assembly Tape Guide Assembly Door Opener B Pinch Arm (B) Pinch Arm (A) Assembly FE Head Prism Slider Shaft C Drive Lever L C Drive Lever R Capstan Motor Clutch Assembly(HI) Center Gear Cam Holder F Cam Gear (B) Mode Gear T T T T T T T T T T T T T T T T T T B B B B B B B B B B B B B B B B
Fig. No. DM3 DM4 DM5 DM5 DM5 DM5 DM1,DM6 DM1,DM7 DM1,DM7 DM1,DM8 DM1,DM8 DM1,DM8 DM1,DM8 DM1,DM9 DM1,DM9 DM10 DM10 DM10 DM2,DM11 DM2,DM12 DM12 DM2,DM13 DM2,DM13 DM2,DM14
3(S-12), Cap Belt (C-1) (C-2) (C-3),*(P-4) (C-4)
[20],[23], Mode Lever(HI) [24]
DM2,DM14 (C-5), *(L-4) DM2,DM14 (S-15) DM2,DM14 DM2,DM14 DM2,DM14 (C-6) DM14 DM1,DM14 DM1,DM14 DM1,DM15 *(L-5) DM2,DM15 *(P-5) (+)Refer to Alignment Sec.Pg.2-4-10
[22] [26]
Worm Holder Pulley Assembly
[22],[25] Cam Gear (A) [20] [29] [30] [31] [21],[25] [25] TR Gear C TR Gear Spring TR Gear A/B FF Arm(HI) Idler Assembly(HI) BT Arm
2-4-1
U25PALDA
STEP STARTING /LOC. No. No. [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] (1) [25]
PART
Fig. No. B B T T T T T T T T T T T R R T DM2,DM15 DM2,DM15
REMOVAL REMOVE/*UNHOOK/ UNLOCK/RELEASE/ UNPLUG/DESOLDER
INSTALLATION ADJUSTMENT CONDITION (+)Refer to Alignment Sec.Pg.2-4-9 (+)Refer to Alignment Sec.Pg.2-4-9
Loading Arm S(B) Assembly Loading Arm T(B) [35] Assembly [2],[25] M Brake T(HI) Assembly [2],[25] M Brake S(HI) Assembly Tension Lever Sub [38] Assembly T Lever Holder [39] M Gear(HYT) [2] [2],[15] Sensor Gear [37],[41] Reel T Reel S [39] Moving Guide S [35],[38] Preparation Moving Guide T [36] Preparation [19] TG Post Assembly [18],[28] Rack Assembly [48] [50] [50] (2) F Door Opener Cleaner Lever Assembly CL Post (3)
DM1,DM16 *(P-6) DM1,DM16 *(P-7) DM1,DM16 DM1,DM16 *(L-6) DM1,DM16 (C-7) DM1,DM16 (C-8) DM1,DM16 DM1,DM16 DM1,DM17 DM1,DM17 DM1,DM17 *(L-7) DM18 DM18 DM1,DM6 Type A *(L-8) *(L-9) (6) Type B Type A (7) (+)Refer to Alignment Sec.Pg.2-4-10
T DM6 (5) (4)
(1): Follow steps in sequence. When reassembling, follow the steps in reverse order. These numbers are also used as identification (location) No. of parts in the figures. (2): Indicates the part to start disassembling with in order to disassemble the part in column (1). (3): Name of the part (4): Location of the part: T=Top B=Bottom R=Right L=Left (5): Figure Number (6): Identification of parts to be removed, unhooked, unlocked, released, unplugged, unclamped, or desoldered. P=Spring, W=Washer, C=Cut Washer, S=Screw, *=Unhook, Unlock, Release, Unplug, or Desolder e.g., 2(L-2) = two Locking Tabs (L-2). (7): Adjustment Information for Installation (+):Refer to Deck Exploded Views for lubrication. .
2-4-2
U25PALDA
Top View
[45] [7] [46] [50] [9] [47] [8]
[14] [13] [11] [15] [39] [40] [38] [10] [12] [37]
[44]
[33]
[42]
[31] [32]
[41]
[43]
Fig. DM1
Bottom View
[19]
[36]
[35]
[26] [27]
[24]
[23] [28]
[25]
[22]
[29]
[20]
[34]
Fig. DM2
2-4-3 U25PALDA
(S-1) [1] (S-1)
[3]
[4]
[5] (S-2) [6] (P-1) (S-3) (S-4)
Fig. DM5
Fig. DM3
Type A [7] [50]
Pin D Pin C [2] A
[51] (L-9) Type B [50]
2 Pull up
1 Slide
Pin A Pin B Slot A
(L-8)
Slots B
(S-5)
Slot A First, while pushing the locking tab as shown in the right, slide and pull up the right side on [2] to release Pin A and Pin B from the slots A. Then, remove Pin C and Pin D on [2] from the slots B as shown. Locking tab View for A
A
Fig. DM4
Desolder from bottom View for A
Lead with Blue Stripe
Fig. DM6
2-4-4
U25PALDA
(S-7) [14] [9] [8]
(S-9) (S-10) [15]
A Desolder from bottom [8]
(S-6) LDG Belt
Lead with White Stripe
View for A
Fig. DM7
Fig. DM9
(L-2)
Adj. Screw [11] (L-1)
[17] (L-3)
After removing the Screw (S-11), while pressing the Locking Tab (L-3), remove [16]. [16] [18]
(P-3) [13] [12] [10] (P-2) A
(S-11) Pin of [12] Pin of [10]
Fig. DM10
Grooves of [28] When reassembling [10] and [12], confirm that pin of [10] and pin of [12] are in the grooves of [28] as shown.
[28] View for A
Fig. DM8
2-4-5 U25PALDA
Cap Belt
(C-1) [20]
[19]
[21]
Fig. DM12
(S-12)
Fig. DM11
2-4-6
U25PALDA
[25] (C-3) [23] (S-15) [26] (P-4) [27] (C-6) [29] (L-4) (C-2) [22]
(C-5)
(C-4) [28] [30] [31] [24]
(P-4) [28]
Pin on bottom of [23]
When installing [23], install the spring (P-4) to [28] as shown in the left figure, and then install [23] while pressing the spring (P-4) to the direction of the arrow in the left figure and confirming that the position of the spring (P-4) is placed as shown in the left figure. [23]
[32] Position of Mode Lever when installed Pin of [34] Pin of [37] Pin of [38]
Bottom View
[25]
[28] Top View Align [25] and [28] as shown. First groove on [28] First tooth on [48] [28] When reassembling [28], meet the first groove on [28] to the first tooth on [48] as shown.
Pin on [22]
[28] Top View Position of pin on [22]
Fig. DM14 Fig. DM13
2-4-7
U25PALDA
Refer to the Alignment Section, Page 2-4-9. (P-5) [34] [33] [36] [35]
[45]
[46] [47]
(L-7)
(L-5)
Fig. DM17 Fig. DM15
[39] (C-8) [42] (C-7) (P-7) turn [44] (L-6) [43] [49] [38] [40] turn [37] (P-6) [48] Slide [41]
Fig. DM18
turn
Fig. DM16
2-4-8
U25PALDA
ALIGNMENT PROCEDURES OF MECHANISM
The following procedures describe how to align the individual gears and levers that make up the tape loading/unloading mechanism. Since information about the state of the mechanism is provided to the System Control Circuit only through the Mode Switch, it is essential that the correct relationship between individual gears and levers be maintained. All alignments are to be performed with the mechanism in Eject mode, in the sequence given. Each procedure assumes that all previous procedures have been completed. IMPORTANT: If any one of these alignments is not performed properly, even if off by only one tooth, the unit will unload or stop and it may result in damage to the mechanical or electrical parts.
Alignment 1 Loading Arm, S and T Assembly
Install Loading Arm S and T Assembly so that their triangle marks point to each other as shown in Fig. AL2.
Alignment 2 Mode Gear
Keeping the two triangles pointing at each other, install the Loading Arm T Assembly so that the last tooth of the gear meets the most inside teeth of the Mode Gear. See Fig. AL2.
Alignment 1 Triangle Marks Loading Arm S Assembly Last Tooth
Alignment points in Eject Position
Top View
Alignment 2
Alignment [a]
Loading Arm T Assembly Most inside teeth of Mode Gear
Alignment 3
Mode Gear
Fig. AL2
Alignment [a]
Bottom View Alignment 1
Tape Guide Assembly
Alignment 2
Measurement of the screw must be as specified in Fig. AL3.
Tape Guide Assembly Screw 3.25 0.1 mm 0.128 0.004 inch
Alignment [a] can be done independently of any other alignment.
Fig. AL1
This alignment can be done independently of any other alignment.
Fig. AL3
2-4-9
U25NAPM
Alignment 3 Cam Gear (A), Rack Assembly
Install the Rack Assembly so that the first tooth on the gear of the Rack Assembly meets the first groove on the Cam Gear (A) as shown in Fig. AL4.
Top View Cam Gear (A) Alignment 3
First tooth
First groove on the Cam Gear (A)
Gear on Rack Assembly
Fig. AL4
2-4-10
U25NAPM
EXPLODED VIEWS AND PARTS LIST SECTION
VIDEO CASSETTE RECORDER 25A-254/25A-654
Sec. 3: Exploded views and Parts List Section
I Exploded views I Parts List
TABLE OF CONTENTS
Exploded Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1-1 Mechanical Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2-1 Electrical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3-1 Deck Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4-1
EXPLODED VIEWS
Front Panel
[ 25A-654 ]
A1X
3-1-1
HC4C1FEX
Cabinet
2L011 2L011 2B18
2L011 A2
2L011 2B9 2B9