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Hello!
I have a K4900 4-pot that came in a Williams cabinet I bought a while ago for restoration. It did work when I bought it although the picture was washed out. I decided to recap the chassis while doing the other restoration work. I also tested the tube on my B&K and it tested very good so I did not use any of the other functions on the B&K.

I followed @mecha's website for reminders of things to reflow including the jumpers, neck socket, signal headers and ceramic resistors. I replaced all caps (including the filter cap) with a kit from AP&R. I double-checked all my work to ensure cap values and orientation were correct, and they were.

I connected my TPG and powered it for the smoke test and for a few seconds the image looked really good. Bright and crisp. Then, it started to shrink vertically, almost like the image was zooming out. Then it started to fade out. I cut power, let it sit a few seconds and powered up again. This time the image was again shrunken vertically and very dim.

When I shut it off this time I caught a whiff of hot component but couldn't isolate it. A few of the resistors in the vertical area like R312, R310, and R315 look like they might have gotten hot - there's some discoloration on the casings and/or the leads, but they all tested correct for their values on my DMM. And they're all in that corner of the board that clear does get hot, so maybe they were already like that.

I consulted the Randy Fromm flowchart for the section for shrunken image:

IMG_7597.jpeg

R313 is the big 470 Ohm vertically-mounted ceramic. I did reflow that one, but it is measuring right on the money on both the component and the solder side.

I confirmed that the caps were all oriented correctly when I installed them and just rechecked them all with the ESR meter and they all seem OK. For Q302 and Q303 I'm seeing 0.5v drop in diode mode from B->C and B->E.

I didn't observe any actual smoke and no other components seem to be visibly damaged. I definitely smelled something getting hot when it was on though.

Any pointers on what to check next?
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