[Ccarc] repeater update Saturday 11-3-07

[psnider at pwrtc.com]

Saturday at 9 am Chuck, Dave and Phil met at the Chase water tank to
work on the 147.180 repeater. The transmitter was having serious problems.
We found that it was only putting out about 6 watts, and sometimes it was
putting out spurious signals.  We found one of the final transistors
(there are 4)
had the collector lead solder had become broken, and sometimes it had
a connection and sometimes it arced over, causing massive noise.
   Repairing the solder connections stopped that intermittent, but sometimes
there was still some noise.  We determined that one of the driver
transistors, (there were two) was not getting warm.  Replacing it didn,t
help, and then the top cover of the transistor came off.  We could see
arcing inside the transistor.
We replaced that transistor again, and also replace one broken paracitic
supressor and now we have 12 watts out. We retuned the transmit side of
the duplexer and now have about 5 watts out of the duplexers. It appears
to be quite, and the desense is 1 db or less, which is quite good.
     We also replaced some coax cable jumpers that were intermittent.
Measurement of the power out of the exciter was 310 mw, and it should have
been 400 mw.  That will be investigated at a later time.
    The receive seems to be working fine, and the transmit power is down
from 90 watts to 12 watts, but hopefully we can all communicate again.
Signal reports will be apreciated from everyone.
     We need to get some spare units fixed on the bench, so next time if
something fails we can replace it and tag it and drag it to the
repair place.
    Phil W9LVY