It appears that I have found the problem in my HRO60. I turned it on one
day last week and all I could hear was floor noise. I couldn't even hear
the xtal calibrator and all drawers(bands) were the same. After much poking
and prodding and tube testing, come to find out the 4H4 has a broken
filament wire, which means that the HF oscillator and the mixer aren't
getting any filament volts. Now I need a replacement 4H4. Anyone have a
spare they would be willing to part with? I have a 7H4B but when I plugged
it in I get 12VAC out to the mixer and HF osc filaments. My HF Oscillator
tube 6C4 is really weak so I need one of them too.
Help would be appreciated.
Bob W6TR Florida