Sony WEGA Color TVs - KV-HA21M50 - KV-HA21M80 - KV-HA21M80/H - KV-HA21M81 - KV-HA21P52 - KV-HA14M80 & KV-HW21M83
Symptoms
Black screen with no sound or bright horizontal line across the screen, standby LED blinks four times, or stay lit.
Total vertical sweep failure is the fault.
Vertical oscillator or output section has the fault. Check all the solder points at (IC551 – AN5522), for any loose solder. Advised to resolder all the solder points of this IC (7 of them) by applying a little more solder to each solder terminals, without making any solder bridge short in between adjacent solder terminals. In most cases, the fault will be of loose solder points to the terminals of this IC. Check (R533 – 2.2 Ohms] for open. If resoldering these points does not help you check the input +ve voltage at pin number 2 of this IC. It should be around 13VDC (+13V vcc). Check the voltage at pin number 4 of this IC. It should be around – 13VDC (- 13V vss).
If (+13VDC) at pin number ‘2’ is absent, check [C501, C504, D503 & R508]. Voltage to this IC is derived from LOT pin number ‘9’. Check all the soldering terminals at LOT for any loose. If found, resolder them by applying a little more solder. If (- 13DC at pin number ‘4’ is absent, check [C502, C503, Zener diode D502 and R507]. All these component numbers will be printed on either side of the printed circuit board, and are easy to detect. If all these components are OK, and still there is no vertical output, check whether IC AN5512 heats up abnormally. If it does, make sure that IC is faulty, and should be replaced.
In most cases this IC fount to be faulty, causing vertical sweep failure. When you replace this IC with a new one, zener diode (D502) should be replaced along with.
Just understand that, the voltages to this vertical output IC is generated by LOT, up to that stage is working fine.
In this model Sony sets, this is a common fault found.
