Dave -
T/R problems are often associated with the 10R and 10T control lines and
their "fuses", Q306 and Q307.
Check both busses, marked on the parent board traces. Each must be very
close to +10 when receiving or transmitting respectively AND very close
to 0V inversely. You'll probably find that the 10R bus does NOT go to
zero in transmit as it should.
Q306 and Q307 are on the Transmit Exciter board. If you don't have a
Service Manual, you'll need help finding them.
Let us know.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs
<www.k4oah.com>
[EMAIL PROTECTED] wrote:
Hi Gents,
I recently acquired my first TR-7 (thank you Evan K9SQG for sharing
and thank you Gary W8PU for some technical guidance in finding a
shorted pin diode). When I transmit on phone, I'm getting some
garbled audio fed back into both the headphones and the external
speaker connected via the rear panel. It's very distracting and makes
it difficult to talk normally. Audio reports from distant stations say
my transmitted audio (Shure 444D) is fine. I'm using a Steppir 2L,
so I don't have a bunch of RF running around the shack and the mic
gain is set to just kick the ALC in on peaks. The garbled audio is
also present transmitting into a dummy load. I'm using an Astron 35A
power supply.
Using the same exact set-up (coax cable, speaker, speaker connection
cable, power supply, etc.) with my Tentec Orion, it's perfectly clean.
Any thoughts/suggestions?
73,
Dave / K8JDC
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