Fred -
There is a slide switch up behind the LOAD control that switches the
meter between the 3 ohm cathode current switch and the RF detector to
reflect RF output.
The switch may need "exercising" or a shot of DeOxit.
If the tubes are NOT actually drawing cathode current, then there is an
"open" somewhere between the Final cathodes and ground. Possibly a
relay contact that closes in transmit.
The Final cathodes should measure about 15 ohms to ground if you
manually close the relay with the power off. The cathode voltage should
be only a volt or so in transmit.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs
<www.k4oah.com>
KC4SUE - Fred wrote:
I last posted a request for help with a T-4XB that would not load. I
appreciated all the help and replies I received .
It turn out to be a cracked Band Selector switch.
I have since acquired another T-4XB from a friend. With this rig I can
not get a bias reading on the meter to adjust the 70 ma bias current.
I've have check the power supply and all voltages are correct. Lamps
and tube filaments are all good.
Bias voltage from Power supply varies with the adjustment pot like it
should, but No rig Meter movement at all.
I check the meter and it is good. Any advice or suggestion will be most
appreciated.
Thank You ,
Fred,
KC4SUE
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