[1000mp] Mark-V Main Receiver Audio Problem

[Scott Galbraith]

Well, over the past few weeks I have come up with a strange problem in the
audio from my main receiver. The symptom is that the audio level has grown
steadily weaker such that I have to crank the volume up almost all the way
(3:00 o'clock or further) to hear stations which are 20-40 over s9 on the
receiver (even using headphones.) Sometimes the problem goes away. Now for
the really strange thing - the problem is ONLY in SSB modes. If I switch to
CW (or any of the other modes) - the volume blasts out at a setting of 9:00
o'clock.
Also, it only affects the audio from the main receiver. The audio level is
great when using the subreceiver (in any mode) feeding either the main
audio chain (AF reversed) or the sub audio chain.

Fact that it works fine in CW mode and in all modes using the subreceiver
makes me think that the audio chain itself is fine. The RF signal strengths
are "normal" so I would not think that the filter chain is the culprit.
Switching GC off makes everything "louder" but the level differential
between SSB and all of the other modes is still the same - so would seem to
rule out that circuit.

Any suggestions on what to check?

-- 
73 de Scott Galbraith
N3OK, Frederick County, MD
FM19ji
ARRL, QCWA 30013, GERATOL 2198, PVRC
NAVMARCORMARS - NNN0OPY, NNN0GAW - MDE/SMD
National Communications System SHARES
scottg (at) n3ok.com
nnn0opy (at) navymars.org
http://www.n3ok.com