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7 Troubleshooting
Notes: 1. If a picture does not appear, fully rotate the brightness and contrast controls clockwise and reinspect. 2. Check the following circuits. · No raster appears: Power circuit,Horizontal output circuit, H/V control circuit, and H/V output circuit. · High voltage develops but no raster appears: Video output circuits. · High voltage does not develop: Horizontal output circuits.
7-1 No Power
Does proper DC 110-366 Volts appear between the positive and negative poles of C606? Yes Does the appear 2'nd voltage of T601 (45V, 72V, 14.7V and so on)? (The condition BD602, BD603, JW71, JW63 are desoldered) Yes Does the appear 45V at D617's Cathode pin? (the condition L501's are pin is desoldered) No Does the appear 45V at D617's Cathode pin? (the condition L403's are pin is desoldered) No Does the appear 45V at D617's Cathode pin? (the condition JW71, JW63 are desoldered) No Does the appear 45V at D617's Cathode pin? (the condition CN102 is disconnected) No Check the IC102, IC101 and another components in Video Part (IC103, IC104, etc). Yes Yes Check the Q406, Q403, Q411 and those are related Horizontal control circuit. (IC401, IC402, Q404, Q401, Q402, Q405, Q408 and Q409) Yes Check the Q503, Q504 and those are related High Voltage control circuits. (IC501, Q510, Q501, Q502, Q506, D508, D517 and D524) No Check D605, C616, C618, components in primary part, the power feedback circuit (IC602, IC603, and its related circuits), D617, D618, D610, D615, D612, D620, D619, IC606 and IC607. No Check the Fuse, Bridge Diodes (D601~D604), IC601, C617 and D614.
Replace the IC301.
CKG7507L
7-1
7 Troubleshooting
7-2 Horizontal Line on CRT or Rainbow Color on the Screen
The first of all you must check CN301. Does the 12V appear at Pin 4 of IC301? Yes Does the pulse appear at Pin 5 of IC301? Yes Replace IC301 and check its related Vertical IC's application. Check R303 and R310. No
7
No
Check the 12V Line at power secondary part. (D615, C620)
WAVEFORMS
7 2.80 V (IC401, #9)
10
Does the sawteeth wave appear at the Pin 9 of IC401?
CH1 P-P = 2.80 V CH1 RMS = 3.469 V
Yes
No Replace IC401.
10 54.8 V (IC301, #5)
CH1 P-P = 54.8 V
CH1 RMS = 6.38 V
7-3 Vertical Line on CRT
Does the drive pulse appear at the emitter of Q401? Yes Does the drive output pulse appear at the Collector of Q403? Yes Does the pulse appear at Gate of Q411? Yes Check Q411 and D408. No No Replace Q403 or check its related circuits. (C416 and T401)
WAVEFORMS
14 15.8 V (Q411, Gate)
43
17
CH1 P-P = 15.8 V
CH1 RMS = 8.37 V
17 140 V (Q403, Collector)
14
Check IC402 and its application.
CH1 P-P = 140 V CH1 RMS = 52.7 V
43 7.12 V (Q401, #Emitter)
CH1 P-P = 7.12 V
CH1 RMS = 4.836 V
7-2
CKG7507L
7 Troubleshooting
7-4 No Raster (1)
Power indicator is green
WAVEFORMS
3 8.56 V (IC401, #18)
Does the +B output voltage appear at the secondary side of T601? (45 V, 72 V, 14.7 V, etc) Yes
3
No
Check the power supply circuits.
Does the output pulse appear at Pin 18 of IC401? Yes Does the pulse appear at the Collector of Q503? Yes Does the DC Voltage (about 10V) appear at Pin 7 of IC502? Yes
No
CH1 P-P = 8.56 V
CH1 RMS = 5.900 V
Check Q404 and its related circuits.
26 856 V (Q503, Collector)
No
26
Check IC501 and its application circuits.
CH1 P-P = 856 V CH1 RMS = 251.2 V
No
Replace IC502.
Does the DC Voltage (200V over) appear at HV_ADJ point (The condition Pin 7 of IC502 is desoldered)? Yes Change FBT.
No
Check HV protection circuits and IC502's application circuits.
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7-3
7 Troubleshooting
7-5 No Raster (2)
Power indicator is Amber. Does the +B output voltages appear at the secondary side of T601? (45 V , 72 V, 14.7 V ,etc) Yes
3
No
Check the power supply circuits.
Does the output pulse appear at Pin 18 of IC401? Yes
No
Check Q404 and its related circuits.
39
Does H-sync appear at Pin 41 of IC201? Yes
No
1. Check Pin 13 of the signal cable. 2. Check the H-sync input and output (Pins 13 and 10) 3. Check Pin 12 of CF202. And then if there are H-sync at Pin 41 of IC201, refer to No Raster (1) troubleshooting method.
Replace OP101 and then refer to No Raster (1) troubleshooting method.
WAVEFORMS
3 8.56 V (IC401, #18) 39 5.36 V (IC201, #41)
CH1 P-P = 8.56 V
CH1 RMS = 5.900 V
CH1 P-P = 5.36 V
CH1 RMS = 1.464 V
7-4
CKG7507L
7 Troubleshooting
7-6 No Video
Power indicator is green and High voltage is appeared. Yes Does DC 6.3 V appear at Pin 10 of SK1 on the Video Socket Board? Yes Does DC 10 V appear at Pin 7 of IC502? No Does the video input signal appear at Pins 5, 8 and 11 of IC101 on the Video PCB Board? Yes Does the video output signal appear at Pins 18, 20 and 23 of IC101 on the Video PCB Board? Yes No
33
No
Check the 6.3 V line at power supply circuits (Q605, D620 and Q606).
Yes
Check the High voltage protection circuits (IC502, L502 and D524).
No
30
Check signal cable and signal source.
31
Does the clamp pulse at Pin 15 of IC101? Does the contrast DC 2~3 V appear at Pin 13 of IC101?
No
Check IC201 (Pin 37) on the Main PCB. Check contrast circuis on the Control PCB and Main PCB. (VR702, Q513, etc)
No
34
Does the video amplified pulse appear at Pins 1, 3 and 5 of IC102 on the Video PCB Board? Yes Check the CN105.
No
Does DC 70 V appear at Pin 6 of IC102? Yes Replace the IC102.
WAVEFORMS
30 860 mV (IC101, #5, 8, 11) 31 3.28 V (IC101, #18,20,23) 33 5.40 V (IC101, #15) 34 40.8 V (IC102, #1, 3, 5)
CH1 P-P = 860 mV CH1 RMS = 2.412 V
CH1 P-P = 3.28 V
CH1 RMS = 2.748 V
CH1 P-P = 5.40 V
CH1 RMS = 4.870 V
CH1 P-P = 40.8 V
CH1 RMS = 46.28 V
CKG7507L
7-5
7 Troubleshooting
7-7 No OSD Displays
There is video but no OSD.
WAVEFORMS
36 5.44 V (IC104, #5)
While pushing a front control button does any pulse appear at Pins 10 and 11 of IC201? Yes
36
No
Check the push buttons on the front control board SW1 ~ SW5, CF201 and IC201.
CH1 P-P = 5.44 V CH1 RMS = 4.408 V
37 5.40 V (IC104, #18)
Does the horizontal flyback pulse appear at Pin 5 of IC104? Yes
No
Check horizontal flyback pulse generation circuit. (T402 Pin 10, Q102)
CH1 P-P = 5.40 V
CH1 RMS = 324 mV
37
Does the vertical blanking pulse appear at Pin 18 of IC104? Yes
No
Check vertical blanking pulse generation circuit. (R125 and IC105)
Does the any pulse appear at Pins 20, 21 and 22 of IC104? (After pushing a front control button) Yes Does the Voltage (about 2.9V) appear at Pin 14 of IC101?
No
Check IC104.
No
Check R102 and R103.
Yes Replace IC102.
7-6
CKG7507L
7 Troubleshooting
7-8 No Specific Color Appears
The raster color is light red or cyan
The raster color is light green or magenta
The raster color is light blue or yellow
Check the red video circuits. (IC104, IC103 and QR01)
Check the green video circuits. (IC104, IC103 and QG01)
Check the blue video circuits. IC104, IC103 and QB01)
Note: Removing the signal cable displays a self raster screen. This screen displays the message "check signal cable" along with red, green and blue boxes. Use these boxes to check whether each individual color (R, G, B) is operating or not.
7-9 Degauss Operation Failure
When you push the manual degauss button, does 5 V appear at Pin 14 of IC201? Yes When pushing the manual degauss button, does the Q608 operate well? Yes Check the D-Coil and PR601.
No
Replace IC201
No
Replace Q608
CKG7507L
7-7
7 Troubleshooting
7-10 Power Save Management System Failure
7-10-1 Stand-By Mode
Does the pulse appear at Pin 37 of IC201? No OK Yes
7-10-2 Suspend Mode
Does +5V appear at Pin 12 of IC201? Yes Does Q604 and Q302 activated? Yes OK No Check Q604, Q302, Q404, D501 and D404. No 1. Check V-sync input (inactive) 2. Check IC201 and its related circuits
Check H-sync input of signal cable.
7-10-3 Off Mode
Does +5 V appear at Pins 12 and 13 of IC201? Yes Does Q604, Q606 and Q302 activate? Yes Does Q605, Q404 and Q603 in active? Yes OK No No No 1. Check H & V Sync input (inactive) 2. Check IC201
Check Q604, Q606 and Q302.
Check Q605, Q404 and Q603.
Table 7-1. DPMS Logic Table Mode Normal Stand-By Suspend Off Sync H Active Inactive Active Inactive V Active Active Inactive Inactive Video Active Blank Blank Blank LED Color Green Amber Amber/Green blinking Amber blinking
Note: If the signal cable is removed, DPMS function does not operate and a self raster displays. 7-8 CKG7507L
7 Troubleshooting
7-11 User Controls Don't Work
Does DC 5V appear at Pin 8 of CN201? Yes Does the DC level change at the positive poles of C201 to C217 when you push the front panel buttons? (See table 7-2) Yes Check IC201, IC202 and RESET circuit.
No
Check the button and CF201_2 connector Ass'y. (SW1 ~ SW5 and SW6 ~ SW10)
No
Check IC201.
Table 7-2. Front Panel Button Location C201 C202 C203 C211 C212 C213 C214 C216 C217 Function Horizontal Size Vertical Position Horizontal Position Vertical Linearity Pinbalance Parallelogram Trapezoid Side Pincushion Vertical Size
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7-9
7 Troubleshooting
Memo
7-10
CKG7507L