Sony KV25fs150 with retrace lines.

[SEAWOLF]

Re: Sony KV25fs150 with retrace lines.

I did not have that exact diagram but I think I have it now, is this the same? if it is, when you disconnect cn703 from the cv board does the voltage +200 volts come back on D523 (K) on the "A" board, and does the error go away?

This is the diagram and when I disconnect cn703 from the cv board the voltage
on D523(K) is high and the error is still present.I unsoldered D523 and checked
the voltage at the cathode and it is is 178v.

[SEAWOLF]

Re: Sony KV25fs150 with retrace lines.

I did not have that exact diagram but I think I have it now, is this the same? if it is, when you disconnect cn703 from the cv board does the voltage +200 volts come back on D523 (K) on the "A" board, and does the error go away?

This is the diagram and when I disconnect cn703 from the cv board the voltage
at D523(K)is high and the error is still present.I unsoldered D523 and checked
the voltage at D523(K) and it is178v.

[R_J]

Re: Sony KV25fs150 with retrace lines.

This is the diagram and when I disconnect cn703 from the cv board the voltage
at D523(K)is high and the error is still present.I unsoldered D523 and checked
the voltage at D523(K) and it is178v.

Saying a voltage is high tells me nothing, What is the voltage at D523 (k)when it is soldered into the circuit and cn703 is un-pluged from the CV board ?
The B+ supplied by the power supply should be around +135-140 volts, it then goes through R5020 and supplies the horz. section, If the voltage drop across R5020 is too great it will trip the ocp.
What is the voltage on the junction of R5020 and R5021
and what is the voltage at the junction of R5020 and D548 (I think it should be around +135 volts)

I remember that on the KV-27fs100's I changed a lot of shorted D517 and D518 diodes, but I cant remember if there was a raster on the screen when one of them shorted, You might want to check them just in case.
Another thing to check that might be shorted would be the Pin amp fet Q505

[dick_barton]

Re: Sony KV25fs150 with retrace lines.

Hello,
Just had a reply from a colleague of mine who was in the repair business for many years. Hope this helps.

Only just seen your message after getting back from Scotland last night. Anyway, the model no. seems to be a Sony. I can't see it being a line driver fault, because line drive is used to create the line scan and the EHT. A fault with that would give you no raster at all, but you have what looks like excessive raster with flyback lines. That would suggest a problem in the video drives or beam limiter circuit, as the CRT guns are being driven too hard, with too low a voltage at the RGB output collectors, possibly with too high a voltage at the bases, which drive the collector voltages down. Have you got a service manual? You will need to know what voltages to expect at the video collectors, which couple to the CRT cathodes. Low cathode voltages mean high currents through the CRT, hence excess brightness as you've got there etc. Hope that gives you a lead. Cheers.

[fredaelsadany]

Re: Sony KV25fs150 with retrace lines.

hallo
if you want to repair your tv please measure these voltages on screen board :
KR
KG
KB
G2 SCREEN VOLTAGE
ONLY
after your measurements we can begin good repair .
thanks

[SEAWOLF]

Re: Sony KV25fs150 with retrace lines.

hallo
if you want to repair your tv please measure these voltages on screen board :
KR
KG
KB
G2 SCREEN VOLTAGE
ONLY
after your measurements we can begin good repair .
thanks

Thank you very much.

[dick_barton]

Re: Sony KV25fs150 with retrace lines.

Any progress on your repair?

[ajterry79]

Re: Sony KV25fs150 with retrace lines.

Im having the same issue as well on my KV-27S42 with 5 blinks on standby, sometimes 2 but mostly 5.

[R_J]

Re: Sony KV25fs150 with retrace lines.

Im having the same issue as well on my KV-27S42 with 5 blinks on standby, sometimes 2 but mostly 5.

Likely a shorted vertical output ic, sometimes the ic's connections are bad and that eventually takes out the ic. Also check for an open R562 (0.47Ω) located off pin 9 of the high voltage transformer