TRK12/120 Restoration

[dtvmcdonald]

I've completed recapping.

I removed the fuse from the CRT HV supply.

With no tubes except the B+ rectifier inserted I brought it
up on a Variac with a meter on the B+. It got up to
normal voltage with not fuss.

I then inserted all tubes except the horiz and vertical outputs.
Or rather, I tied to. It seems I ordered the tubes for a TRK-120
and I've got a TRK-12. I'm missing a 6F8G and a 6H6.
However both of these, despite what the specs say, are
being used as single diodes. They were temporarily bridged
with (hold nose) silicon.

Again bringing up on the Variac caused no fuss.

Did I mention I was feeding a signal in? I checked the oscillator
frequencies and they are set for modern channels 2-6 as a
rubber stamp on the chassis says. It was set to Ch. 2.

Checking the signal path with a scope showed that it was getting all the way
to the outputs (audio and video).
Fine tuning and contrast (actually grid bias on all IF stages) wore
as expected. The video waveform actually looks rather passable.
The sound sounds OK on 2000 ohm phones (remember that it has
no amplifier.)

Next I checked the sync separator chain and it works fine.
The horizontal osc works and the hold works but the pullin
range is rather small. Is this normal for TRK
12s?

No sweep was getting to the horizontal output grid (no tube, remember).
This was traced to a bad width pot. Turning it caused drive to appear,
and disappear, with loud pops from arcing inside it. I have a modern
one that should work if it can take 300 volts.

The vertical system worked correctly, but again with rather small pullin range.

The B+ for the 2nd sync separator is 7 volts [sic] as shown
on the schematic.

So much for today!