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Field Problem Reports Model
KV27S10
Subject
DEAD,REPLACED Q601, Q602, AND R607 HIGH PITCH SQUEAL NOISE FROM HLC, TECH FLASH NO.100 PART NUMBERS MISSING FROM SERVICE MANUAL, NO RESISTOR JUMPER
Repair Tips R607 was open Q601, Q602 shorted, replaced parts turned unit on and R607 opened, Q602 shorted. Lifted HLC L509 1/16 of an inch and resoldered, added tape to the board corner Part numbers for R651, R652 missing in service manual. These resistors are jumper wires. No resistors are use. Unit came in with shorted parts in switching power supply. Caused by an excessive load. Deflection yoke was source of problem. It was shorted between the vertical and horizontal windings, which is very unusual. Replacement of yoke along with standard power supply parts resolved problem. Note: Power supply is not protected against all forms of load problems. It is necessary to use proper service techniqures to distinguish between a load or supply caused problem. Some cable channels has distorted picture. Replace the tuner solved problem. 859825400 TV has sound and B+ is ok, but no high voltage.Found cold solder on Emitter and Base legs of Q581 (hot). Re-soldered above legs, then TV works fine. No picture but has sound. Found low voltage on G2 pin 5 crt socket... Found R701 open. Video was red with retrace. Cooled IC301 with freeze spray pictures went blue with retrace. IC-301 signal going in was OK but had low RGB output to the C board. Vertical was down about 2 from top. checked voltage on TP98 and read 1.8v. Checked another set and TP98 should be 11.8v not 15v as schematic states. Traced problem to R539 had changed value from 39k to 41k which was just enough to cause vertical problem. Traced problem to IC101. R539 is across R531 (off of IC501\pin 7) which supplies input to the vertical output. Taps off FBT are not always precise Picture shows bad pincushion. Check pincushion circuit and found incorrect wave form at pin 5 of IC504 (pincushion
KV27S10
KV27S10
KV27S10
DEAD, REPLACED YOKE
KV27S10
DISTORTED PICTURE WITH SOME STATIONS, TUNER PROBLEM NO PICTURE, COLD SOLDER ON Q581(HOT) NO PICTURE, REPLACED R701 RED VIDEO WITH RETRACE, REPLACED IC301
KV27S10
KV27S10
KV27S10
KV27S10
VERTICAL DOWN ABOUT 2 IN FROM TOP, REPLACED R539 & IC101
KV27S10
DIDTORTED PICTURE, PINCUSHION, REPLACED C540
control IC). Signal had flattened top. Found wave shaping cap, C540 was open.
INSUFFICIENT VERTICAL, YOKE
KV27S10
Picture pulled up about one inch from bottom. Adjusting controls allowed picture to fill out but centering was off. When centering was adjusted picture folded over. Replacement of yoke resolved problem. Resoldered pin 3 on comb filter block. Pincushion problem. Adjustments did not work except 2 inches on the top of the picture. All main parts in pin circuit were replaced. All incoming pluses were correct. Discovered that voltage on Pincushion control IC504/pin 6 was 4.5 volts instead of 3.6dc. Replaced defective protect module PM501 on the D board. Removed IC301/pin 38 and unit worked , but picture was in blanking. Check IC501/pin 1 read -15v should be 3.6v. Found R759 was open. Found R759 located on the emitter of Q563 was open. The part number is 9-908-960-01 The original Varactor VDR601 in this set is a black colored, 280 volt varactor voltage device. The varactor being supplied by WRPC-AS under this part number is red colored. The redcolored device is best suited for use in other product types, but for these TV models part number 1-801-074-11 should be used.
KV27S10
INTERMITTENT VIDEO, RESOLDERED COMB FILTER/PIN 3
KV27S10
PINCUSHION ,
KV27S10
IMMEDIATE SHUT DOWN, R579
KV27S10
REMOTE BATTERY P/N INCORRECT, 9-907089-01
KV27S10
Varactor VDR601 from WRPC-AS is different than original.