[Jayce]

I finally dug my RCA 15K out of hibernation today and decided to play it some this evening. Still seemed to be playing well, so I actually aimed it out the front door and let it play away while I was outside enjoying the evening. Upon shutting it down, I made a check for any unusually hot parts or cold tubes (metal tubes, no glow) and found one of the 6H6 tubes was cold as it could be. Popped it in my checker and it didn't even draw any current, which meant the filament was gone. Luckily, I had one brand new 6H6, so I popped it in and tried the 15K again. It was playing well before, now it's a total beast. The fidelity is even better and it can REALLY shake the house and property now. 960 out of Wooster, Ohio brought on 'I Love Rock And Roll' by Joan Jett, so I put the 15K on high fidelity, full bass, cranked it a bit, then stood and felt the porch shake as the RCA cranked out the tune. Definitely not letting this radio get buried again and I will make a note to check all the rest of the tubes later. The 5Z4's and 6L6's were new when I got this radio, so I'll concentrate on the receiving tubes.

[Arran]

Jayce, make sure that you give the audio output circuitry an overhaul before you play the set too much, as well as the power supply. Leaky caps and drifted resistors can make short work out of audio output tubes by screwing up the bias, and can burn out things like audio interstage transformers or tone control pots. The audio amp always runs on the highest voltages and the highest currents, so things often fail there first.
Regards
Arran

[Jayce]

The radio is already recapped. Basically, my late friend redid the radio for another friend of his, who left it sit for ten years, then he went over it again before I bought it several years back.

[PhilcoJohn]

Yes those high tube RCA radios are great radios. As my 816k and my smaller tube c-11-1 beasts!