Restoration of RCA 8TS30 #C061765

[Penthode]

Originally Posted by ChrisW6ATV

I checked all the tubes and resistors. Three weak tubes, and the 5V4 was replaced with a 5U4. A few resistors too high in value, and of course a chassis full of wax capacitors and bad electrolytics. I had most of the replacements for the wax caps in my kit from Just Radios, picked up the resistors and a few caps locally, and ordered the rest from Digi-Key tonight. I also picked up one tube locally and stole a couple of others from a beat-up 630TS I have as a some-day project here. The fuse is odd; it is in line between one filament connection and another, in this parallel-filament set. Who knows why it would have been added?

I will start the re-capping in the next few days. Here is the "before" picture:

You cannot replace the 5V4 with a 5U4 in this set. The 5V4 is the damper diode and the indirectly heated 5V4 will have the appropriate characterisics for high frequency rectification. The directly heated 5U4 will not. In fact the 5U4 may help destroy your flyback transformer.