Amp repair, its always easy once you find it.

Working on a customers Palomar 90A. Yeah, I know, but he is a local and a decent guy, not like a 'friend' who recently stabbed me in the back, and I eat sweep tube amps like this, especially Palomar for breakfast, in my sleep, so I took it on.
This one is just a quick one on a pestering little buggy problem that almost got me. Well, got me is the wrong word. It bugged me and had me pulling out my hair for a minute. Screen voltage had voltage coming in, but nothing going out. Looking at the schematic, the screen supply runs voltage to the tubes on high, tetrode turbo mode, but it grounds the screen voltage on low, grounded grid mode. After more testing, found that the screen was actually being grounded on High and not on Low. More testing showed that someone put the High/Low switch in backwards. Something stupid like this can make me hate my life.

[@spaceflight1019]

Don't forget to freshen up the solder joints. After 50 years a cold joint will make you pull your hair out trying to figure out why it's not working right.

[@tramdr]

that and tighten those PCB mounting screws and if it has loose rivets, get rid of the rivets and bolt it down.

[@spaceflight1019]

@@tramdr If you don't do that to a TRC-459 it will squeal on transmit. I've seen this on other radios too.