Quote:
Originally Posted by DaveWM
I would check the grid of the HOT for bias, maybe a leaky coupling cap.
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Yep, the culprit was some bad caps around the HOT. Specifically, the multi-section electrolytic C422. I haven't replaced any of the other electrolytics yet or even touched the lower chassis, but I will. It's running pretty darn well right now and I can't wait to see how much better it might get with a full recap.
I also discovered several dubious repairs like these two 0.001 MFD caps in the sync inv. / disc. circuit. I have no idea what type of cap is correct or what the voltage rating should be.
I just went with what I had on hand - 630 V poly caps. Does anyone have a parts list for a 20A1 chassis that does specify these caps?
Also the original 8.2K power resistor in the HV cage is open and was bypassed at some point with the smaller green one. That's a shame because I really like that old style ceramic resistor.
I'll try to dig up one that looks better and mount it properly.
There's an interesting metal hoop under the HV rectifier tube. I wonder what that's for?
Here's the first picture I got using rabbit ears and local lower power channel 6 using a 5AXP4 test CRT.
And here it is using the 10BP4
The CRT is brighter than I was expected based on the weak test reading. I guess time will tell.
It's nice to have an easy restoration for a change
