Grandma just called me, she said she went to her family room to watch TV, and nothing. totally dead like its not even plugged in.

I havent went out there yet to pull the chassis out to see whats going on.

I worked on it once before, it turned to a solid red picture, with no green and no blue when it screwed up before.. I replaced the main IC to restore the color. and while i was in there, i replaced the 10UF cap in the STK circuit as they had a tendency to dry up causing diode/STK failure.

Well im assuming the STK has failed for the first time. hehe. not sure though.

Can't say I've worked on one, but here's a dump from a repair database.


Cheers,

Are you sure it's a 167? I don't remember those having an STK regulator. However, the 176/177/187 sets did and I've seen many where the 130V B+ diode off the secondary of the switching transformer would short and take the STK with it. There's also a resistor in the STK circuit that will open and cause the power supply not to work. I can't remember the value; but, I think it's at least a one megohm resistor.

That resistor in the SMPS you mentioned is 1M ohms 1/16W resistor. Tiny.

By the way STK ICs are out of production, takes quite search to find remaining stock or used pulls. Very important that capacitors are replaced and checked all short circuits since they fail two ways by overload or bad caps.

Cheers, Wizard

And, there are a lot of "knock off" STK's out there that are inferior to the real thing and they usually don't last long, if they even work at all.

oops.... im sorry. I meant CTC177.


I had an ATC113 where the 1meg resistor opened up. Worked great for years until the flyback went out... twice.... so i junked it.

the flyback shorted the first time, and the focus/g2 block shorted to HV the second time. 4 months later.

oops.... im sorry. I meant CTC177.

Ok then:




Cheers,