Antique Electronics and Vintage Solid State
HP 650A Output Divider Cable
Someone on the Antique Radio Forum was asking about the HP 650A test oscillator. They are beautiful vacuum tube R-C test oscillators. The 650A was originally supplied with a Model 65A-16D Output Divider Cable, but they are invariably missing when you acquire a 650A.
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HP 400C oscillation
I'm restoring an HP 400C AC VTVM. I've re-capped it, checked all the resistors, replaced the selenium filament rectifier, etc. I'm most of the way there. However, I started calibrating it and ran into a problem on the 100 volt scale. …
General Radio 1214-A Unit Oscillator
I'm working on a General Radio 1214-A Unit Oscillator.
The oscillator is fixed tuned but can be switched between 400 Hz and 1000 Hz.
It's a cute Hartley LC audio oscillator using a single 117N7GT as the rectifier for the transformer-less power supply and as the pentode for the oscillator circuit. …
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