[Johnson] Johnson 500 bias voltage
Robert Nickels
ranickel at comcast.net
Sun Jan 29 16:25:02 EST 2017
Working my way through a basket-case Johnson 500 power supply-modulator
and have a question that someone who'd been there and done that might be
able to answer. The book specifies the bias voltage at -150VDC but
I'm seeing over 300 volts unloaded and around 225 with just the slow
release and HV relays engaged (PTT keyed). This is without the RF
unit connected and that load will further reduce the voltage, but I'd
like to verify that it's OK before doing that. Most of the iron on
this deck has been replaced but the LV transformer is the original based
on wire colors, so I'm hoping that it's just the way it is without load.
Thanks and 73,
Bob W9RAN
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