56 Philco

[Adam]

I got my 56 Philco to work yesterday. I had replaced all the old wax caps and electrolytics, but it was still lacking in vert size. After checking the voltages on the vert osc. tube, I found that the plate was only 40 for 105, and the grid was +2 for -42. This first made me think that the resistors between the power supply and the vert. circuits were burned out, but this wasn't so. I put the scope to the circuits, where it was outlined in the schematics, and it was very interesting, the waveform was correct, but too small, as would be expected, but lots of duplicates kept flickering in and out, that were out of phase with the brighter original. I figured this couldn't just be a resistor, so I checked the vert osc/output tube again and it was still good. I had already checked all the tubes, replaced all the wax capacitors and checked the resistances at the tubes in the sync circuits before I had turned it on, and they were all ok. I had decided it might be that I had put in a bad capacitor, and tried replacing them again, this didn't help. I had begun to wonder about a .0068mfd mica cap connected to the grid of the vert. osc. tube same as the vert. hold control, and checked the resistance at that point on the tube again. It was only 40K for a supposed 1meg. I checked the vert, hold control seperately and it was good. At this point the only way in which this part of the tube could be connected in any way to ground was through that cap. I took it out and sure enough, it was bad. I made sure it was discharged and it still registered about 50K on my ohm meter, and rated up around .02 mfd on the capacitance checker. I put in a replacement and the set worked fine. After I had spent all day working on this set I was very happy to see it working, I think few people understand how exciting and interesting tv repair can really be.
What is odd about this is that I had checked the resistance at that point an the tube before I started the set, and it was good, which means the cap must have gone bad the moment the set was turned on. This is the first time I have ever seen one of these caps go bad, is it a common occurance?
Also I can only adjust the fine tuning to either get a really good picture or really clear clear sound. When I adjust it for the picture, there is some buzzing. Usually I can usually fix this by adjusting the AGC control, this set dosen't have one. What might I do to repair this?
And does anyone know where I might find an original volume control knob for this set?
thanks for any suggestions, Adam