Sounds like the problem started out with an intermittent solder connection possibly on the deflection PWB unless the power relay has a bad connection or is breaking down under load. If it is not the power relay, I would check the connections under the deflection board - paying close attention to the area from T701 and T752 including the Horizontal output Transistor for a short. You also have a possibility of defective filter capacitors causing the problem as well.
The relay would be the next thing I would change. They have been known to fail in that model. In order to properly test the capacitors (Electrolytics) you would need an ESR meter and possibly a capacitor meter as well if none of them look like their tops are rounded or lifting off the circuit board. The part number for the S901 power relay is FJ00142 and should be available from parts suppliers still. If you have any problems, the manufacturer number is ALKS329, and you may be able to get it from places like Digi-Key or Mouser Electronics.
I replaced the relay - the issue still remains. I will check for shorts on Deflection board. Is that the convergence board? Seems odd if it were a short on this board that it would work intermittently.
I'll also look at the components for physical defects. I only have a standard volt meter. I suspect I can't check caps with it.
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Thanks for the help. I put the old convergence chips back in - they really were not bad in the first place (I had bad CRT coolant that was making my image blurry). After putting the old chips back in, the problem is still there. I checked all solder joints on the IC's - I didn't see any issues - but I could have missed something. I am an IPC certified solder trainer. However, I am not an EE or electrician.
I checked the 2 relays on the PWB and I get equivalent resistance on the coils.
I'll look at the board again.
Is the deflection board the convergence board?
How can I check the capacitors? Also noticed LED's in the back of the TV turning on then off with power - don't know if any of this helps you diagnose.
I paid $3500.00 for this TV 9 years ago. I'd like to salvage it. I hope you can stick with me through this problem.
Just thought of another pertinent item. When I changed my convergence chips, I also worked on an issue on my PWB. The red power light stayed on all of the time - even when you would turn the TV off. I found relay S091 (i think) to be stuck closed. I tapped it with a screw driver a couple of times and it opened up. When I powered the tv back up - the PWB was functioning properly. It was a couple of weeks later that the power on issues began. Do you think that relay may be faulty?
I'll order the relay and replace it and see what happens. It may be the weekend before this gets done. I'll post what happens when I complete the replacement.
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