[Drake] T-4XC 10M Low Output

[Eric Tichansky]

Hello ALL!

Requesting any suggestions on what may be the cause of low 10M output on =
my T-4XC with regard to the following:

When T-4XC is slaved to R-4C for freq control the output is fine (120 W =
on my W-4); this should mean all circuitry after the premixer is working =
fine, this includes RF and INJ trimmer adjustments.  When T-4XC is =
operating on its own local oscillator/PTO (SEP or XMTR), power output is =
very low (10 W).  It seems to point to the PTO/XTAL Osc section, but all =
other bands (160-15M) function perfectly when both =
slaved/mastered/seperate; so the PTO should be fine. Also I have swapped =
10M osc XTALS (39.1 Mc for 28-28.5Mc) with a known working crystal, and =
the output is still low.  The PTO/XTAL osc section seems to provide =
adequate injection on 10M to the R-4C when the T-4XC is master, as I can =
find calibrator signals and receive adequately.  By this diagnosis, its =
seems all is working fine!!

As a note, I performed a modification in the T-4XC to simulate the =
TRANSCEIVE switch in the RCVR position with a 4PDT relay.  It is keyed =
active via a footswitch and was setup to allow instant VFO switching =
during contesting by cycling between the T-4XC's VFO and the R-4C's VFO. =
 I initially suspected the extra shielded cabling to the relay to be a =
problem (extra cpacitance, etc.), but this phenomena is being observed =
without the relay being energized, so essentially all signals to the =
premixer, regardless of origin, are being routed through the same =
cabling, and all control is by the manual TRANSCEIVE switch on the front =
panel.

Are there particular test points that might lead to problem isolation.  =
My only test equipment is a volt-ohm-amp meter, which may not prove =
adequate.

NI3S


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