Re: 7854 Repair & Restoration


On 13 Mar 2016 19:42:25 -0700, you wrote:

It did not fix the problem. Hmmm.....

I'll go through the voltages around the vertical amp board tomorrow. I need to try and sleep off the rest of this sinus infection.

What do you think the chances are that U50 is going bad? I suppose it couldn't hurt to have a spare anyway... I can just buy one, swap it, and see.
I cannot say that it is impossible that U50 went bad causing the
problem but I hoped it was something else like a cracked solder joint
or open resistor.

Replacing U50 can certainly be done but I do not know that anybody
knows the tuning procedure for adjusting R43, R47, L133, L163, and any
other selected parts. Transient response adjustment will be tricky to
impossible without a 7000 standardizer and reference level tunnel
diode pulser but I think you can get close enough for practical

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