Problem: After 20 seconds or so the Titan input SWR increases to over 3:1
from it's normal 1:1 SWR and afterwards is intermittant, sort of cycling,
back and forth between a high SWR and a normal input SWR. When my FT-1000
exciter "sees" the high SWR, it, of course, drops the excitation power to
practically nothing.
This problem turned up a couple of weeks after lightning damaged several
pieces of equipment in my shack, but not the FT-1000 which was not connected
to the Titan or an antenna. I think an antenna was connected to the Titan.
Both the FT-1000 and Titan were plugged into AC lines, but the circuit
breaker for my shack was in the OFF position (the lightning charge still
might have jumped across the breaker).
Anyway, it took a while (first checking the antenna, coax, and switches
for an intermittant) before I finally grasped the nature of the problem while
running power from the Titan into a dummy load on several bands and watching
the SWR of the FT-1000 fluctuate on all bands. My guess was that something
was heating up, but what?
I talked to Rick Long at Ten Tec who suggested I examin the low pass
filters, the bias diode on the rectifier board in the PS, relay K3, the band
switch, and components on the input bias board. Since I am not an
experienced technician, he suggested I send the Titan and PS to Ten Tec,
which I hate to do if I can possibly fix it here.
Today, I examined the Titan low pass filters and bandswitch, seeing
nothing at all suspicious. I have not examined the bias diode in the PS or
K3.
I also examined the bias board and found that R1 is obviously charred.
Checking associated components with my multimeter, I'm reading aprox 2.85K
and 8.5K across both D7 and D10 while in the circuit, whereas I'm reading 910
ohms and 160K across similar looking diode D5. Humm.
Please don't make the mistake of believing I know what I'm doing or
understand the circuit. I wish I did! It does appear to me that D7 and D10
are damaged along with charred R1 which reads close to its normal 10K when
cool, but obviously has been heating up and is damaged.
Can some one suggest futher trouble shooting???
I guess I have several options:
1) I could replace R1, D7, and D10 and hope that solves the problem.
2) I could follow the troubleshooting suggestions of a patient elmer from
here on the Ten Tec reflector.
3) I could call Ten Tec and see if I could return just the input bias
board for repair or replacement and hope a new or repaired board solves the
problem.
4) Perhaps you can think of other alternatives?
I would very much appreciate your input and suggestions.
Doug W0AH Woodland Park CO
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