I have run out of ideas. One of my TR7s has intermittent output power
problems. Sometimes there is no output, sometimes there is 40 to 10 watts
output depending on band and sometimes there is full output.
When I change bands there usually is no output as well as low receive
sensitivity. When I tap the PTT button on the mic the receive comes up to
normal and I usually get 40 to 20 watts (CW) out on transmit. Sometimes when
I push on the High Pass Filter section boards I get full output, sometimes I
don't. Sometimes I get full output when talking into the mic (with the PTT
button depressed of course) and not doing anything else. I searched the
archives with little luck.
What I have done so far:
1. Pulled all the boards and reseated them (some numerous times).
2. Loosened and tightened all screws I could get to, externally and
internally.
3. Cleaned all switches at least twice.
4. Pulled the power supply board and replaced C2108.
5. Readjusted 10 volt supply and checked Fixed pass band adjustment (all
good).
6. Checked 40, 13.695, and 8.05 Oscillators (all Good)
7. Attempted to do Transmitter Alignment and ALC Adjustment but with only
intermittent power output it was hit-and-miss at best.
8. Disconnected Diode CR1402 on the High Pass Filter Board (no change).
9. Checked 10 Volt transmit voltage on Parent Board when in transmit (right
on 10 Volts).
10. Changed out the T/R relay twice ( no change).
11. Changed cables and dummy load (no change).
12. Cussed a lot (didn't help).
Any ideas where to go next other than crazy?
Steve W7JSC
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