A few weeks ago I started working on putting a TR-4C back on the air. I posed a
question about the bias adjustment. I finally got back to working on the
transceiver and still have some questions. I have followed all the information
that has been sent to other people with bias problems, but that info has not
helped me.
My problem is that the bias current is not displayed or changed on the Plate
Current meter when I adjust the bias control. I can measure and adjust the bias
voltage on the final grids so I know the system is working, I just can't
measure the current. I have done most of the suggested things: loosen and
retighten most ground screws, pulled and checked all tubes and used Deoxit on
the pins and reinserted multiple times to clean the pins and sockets and
cleaned the contacts on the relays. The 48 volt relay only has 26 volts on the
pins, but it appears to pull in okay and work. Is 26 volts normal?
Using the Drake manual instructions for bias adjust, no plate current reading
is detected even though everything seems to be working. With the sideband
switch in the clockwise position (opposite what the directions say) and
transmitter gain full counterclockwise, I can adjust the plate current with the
bias control. I also get full power output and can control the plate current
with tuning and loading.
It seems everything is fine except being able to measure the bias current with
the recommended setup procedure.
Any suggestions would be appreciated.
73
Richard
kc9ub
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