[R-390] Pulling tubes, troubleshooting RF deck

[Bill Kulze]

Hi, long time list member, haven't posted a thing in years. Interesting about the tubes in tight spaces topic. My 390a has been stored away for a while, haven't done anything with it until a week or so ago. No output. Tested all the tubes on the RF deck, test good, probably same tubes in question. I could get fingers on them, not necessarily both on the same hand, lol, but not much grip and took lots of wiggling. I need to clear off more space to work on it. I can inject 455kHz to the IF deck and get output. I can inject 455kHz at E211 and hear it. I see no output from the pto with a scope at the end of the cable, and I can inject 2MHz to 4MHz into the RF deck from a generator and there is no output. Still checking voltages at the tubes, but haven't had a chance to get too far yet or check resistances. Reg 150v is good, filament to pto is good. I don't see very much drop in the B+ to the pto, wondering about that. The osc inj voltages at E209 and E211 are not what they should be, can't recall right now, but at E210 it was good. Seems like E402 wasn't right, but like I said, I need to make some bench space so I can dig a little easier. In the meantime, if this rings a bell for anybody... ; )

Thanks, nice to see this list keeps going.

Bill W2NVD
USAF, Ground Radio school at Keesler, spring '77.
Back when they fogged the Triangle with DDT at night for the skeeters.
I'm sure there's a few more out there.