DW Holtman <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Hello again,
Thank to all who E-Mailed with help for my errant T-4XB. When I asked
the question about the cathode of V-3 (Pin-7), I was not smart enough to
read instructions. After putting the rig in tune mode (as stated in the
chart for voltage measurements) the voltage read fine.
The problem still persisted. Next, I warmed up my trusty URM-25 and
first injected a signal on the plate of V-3, Pin-5 and adjusted the
tuning/loading knobs for around 50 Watts. Great start! With a little
bit of drive, got power out. The driver and finals are probably good,
or at least usable.
I next went to V-8, the Pre-Mixer. Injected the correct signal on the
plate (Pin-5) and again had around 50 watts out. I looked at pins 1
(xtal osc input) and Pin-7 (VFO input) with an O-scope and both had a
clean signal that changed with the band switch or tuning knob for the
VFO. I next injected the correct frequency signal on both pins 1 and 7,
with no output. I think that V-8 is bad. With a signal applied to the
output of V-8, power out. Both input signals look good. All voltages
look good.
My Tube Tester a Heath TC-2 does not have data for testing this tube a
6HS6. I think that V-8 is bad. any ideas or suggestions to the contrary
would be welcome. I'm going to order one tomorrow and check it out
again in a couple of days when the tube arrives.
Thank you again for all of the help.
73's
DW Holtman
WB7SSN
Hello,
I'm working on a T-4XB which has no output. The Power Supply had some
ripple of the 250 Volt output, so I rebuilt the Power Supply. Replaced
all of the lytics. Replaced the diodes with heaver duty 1N4007's.
Replaced the 2 conductor cord with a three conductur grounded cord.
Replaced the .01 noise caps with X1/Y2 discs and changed out the 1 watt
bleeders with 2 watt resistors.
On the transmitter, I tested all tubes, changed out the only 2 paper
caps thqat I could find, and cleaned all switches, tube sockets etc.
Now there is still no output. Measuring voltages, I found that the
cathode of Tube V-3 on Pin-7 has 143 Volts DC on it. I know it cannot
work with more than a couple of volts on the cathode. Any
ideas/suggestions?
Thank you in advance for any help.
Best,
73's
DW Holtman
WB7SSN
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