Color problem with Zenith
 

I have a Zenith color tv from 1996, model SR2768S, serial: 621-42031090.

The blue is gone. I replaced the blue output transistor. No improvement. Don't know where to go now. There is an blue adjustment pot on the board near the transistor--should I mess with that? Would a pic of the board be helpful? It looks to be in good condition--all solder joints nice and no broken traces. Any ideas? Thanks very much.

000

Hard to say. I think suddenly. Didn't watch it for a few years, then recently noticed that I didn't see blue. It may have been unknowingly on for a long time--like a month--my wife had turned off the cable box, but neglected to shut off the tv. Could that have caused it?

The CRT would be the first thing I'd check as those Zenith CRT's from that time period are some of the worst ones ever made. They will lose emission and/or intermittently short and blow parts in the power supply and/or video output circuit.

Also, there are some driver transistors ahead of the output transistors. These are located on the main chassis. I've seen those fail due to a shorted CRT. You can replace the transistor and it may work for a week; then, the CRT will arc and blow it again.

I used to get these sets with bad CRT's from a local Zenith repair shop when they were only 2 or 3 years old. Sometimes, I'd get lucky and find an older one with a good CRT and take 2 sets and make 1. '90's era Zenith CRT's were bad with '93-'95 being the worst.

Well, short of replacing the CRT, is there any remedy that I could perform. I can solder, but I have no diagnostic knowledge with tv. Otherwise, I'll chuck it. Sad, really, because it's so nice and big and works fine otherwise.

Try switching the leads to the Red and Blue transistors. If you now have Blue and no Red, the transistor or its associated components are bad.

Ron

Junk it?
 

If you don't repair it and it has a 1298-03 crt module, I would be interested in it. The SR2786 used that module but I don't know about the SR2768.
Thanks

I will check.