Experience soldering TV boards

[BishopMVP]

Started having problems with a 2005 Sony HDTV (Wega KP-46WT520) a few days ago. Occasionally/Rarely will turn on, but almost always you can hear audio with no video, then shuts off after a few seconds. Standby light blinks either 5 or 10 times, which means the problem is either bad soldering on the D board or a bad part on the A or C board.

I have basically no experience working on computers or electronics. Is this something I should even bother trying to look at (I haven't yet tried to take off the back panel) at fix myself, or should I try dealing with Sony technicians/calling a TV repairman? (I assume I could get a TV repairman out here, but that could cost $300-400.)

[CU Tiger]

If you dont have a good deal of electronics experience and specifically soldering experience, and a quality solder gun there is a better chance that you will screw something else up than fix the problem...

[cartman]

If you are comfortable swapping components, you might try to track down the replacement part, instead of trying to tackle a soldering project.

[CU Tiger]

I have to wonder what are the chances it is the flyback transformer?
Have you researched that?
That would lead to video but no sound and then circuitry shuts the wwhole thing down for a safe mode.

When I was a Sony dealer their tube TVs were very reliable but when we had problems it was either the flyback xfmr or convergence board issues in all but 1 case.

[BishopMVP]

Originally Posted by CU Tiger

I have to wonder what are the chances it is the flyback transformer?
Have you researched that?
That would lead to video but no sound and then circuitry shuts the wwhole thing down for a safe mode.

When I was a Sony dealer their tube TVs were very reliable but when we had problems it was either the flyback xfmr or convergence board issues in all but 1 case.

It's sound you hear with no video, so I doubt it's a flyback transformer. This site - Understanding Sony Television Blinking Codes: TechLore - seems to lay out what the blinking means (I get either 5 or 10 each time), and both seem connected to the power supply. I'll try doing the diagnostic screen if I can get it on again and try to narrow it down before I call out for help.

cartman - if I knew which part it is, I could try doing that, but without narrowing it down first I'd have to order an abundance of little parts which seem out of stock at SONY.

[CU Tiger]

Originally Posted by BishopMVP

It's sound you hear with no video, so I doubt it's a flyback transformer.

Which is exactly what makes me suspect the flyback....
The purpose of the fb xfmr is to generate the high volt high hz waves required to create the picture.

If you have sound and no display, its most likely the flyback, the power supply, the tube, or the display board.
I doubt its the power supply because that model uses digital sound processing so if the power supply was bad altogether you wouldnt get sound out or it would sound very distorted.
You say you are getting occasional picture but it doesnt stay long...tube out
flyback or display board

Ive sold/installed probably 700 Sony TV sin the last decade.
Ive had probably 50 warranty repair issues.
of those Id say 30-35 fell into convergence board issues, clearly not the problem here. All but 1 other one were flyback xfmr issues and that one was a damage issue. that doesnt make it scientific but it gives me one hell of a hunch....

Either way I dont repair them I just take them to our local dealer...I just know what I always end up with....

[BishopMVP]

Originally Posted by CU Tiger

If you have sound and no display, its most likely the flyback, the power supply, the tube, or the display board.
I doubt its the power supply because that model uses digital sound processing so if the power supply was bad altogether you wouldnt get sound out or it would sound very distorted.
You say you are getting occasional picture but it doesnt stay long...tube out
flyback or display board

Sorry, I probably worded that poorly. You can hear audio with no video everytime when attempting to turn it on, then almost always it shuts off after a few seconds. Occasionally/rarely it stays on past those 4-5 seconds, and then will stay on for as long as we want.

(Unfortunately right now when I turned it on the video is less crisp, possibly from moving it to look at the back and re-adjust cables. Or from when my roommate thought hitting it might fix the problem. Might just be worth getting a repairman out here before further damage occurs.)

Either way, thanks a lot for the help.

[stevew]

i dunno if this helps, but they might have the parts you need here?

http://beta.searspartsdirect.com/par...chTerm=flyback