[600MRG] Need some help with a receive problem on my TS450S

[Andy - KU4XR]

Greetings all:

My TS450S started dropping the receive intermittently.. It would go off, then come back on..
This is definitely not the speaker coupling cap issue. When the recieve goes out, everything
else on the rig still works.. it will TX. AND.. get this.. I can press the " AIP " button and the
receive works, at 10dB down, which is what that is supposed to do.. I can press the AIP again,
and the receive goes out... Totally.. No RF action from the rig.. the S-meter goes to zero,
the hiss from the speaker goes away, This is not like disconnecting the antenna.. doing that,
I can still hear the audio hiss in the speaker ( when it is receiving that is ).. I have checked
for loose wires, bad solder joints, even went so far as to drench the IF, and RF boards with
spray Electronics parts cleaner... The receive still comes, and goes.. There is no popping,
or crackling noises when it does.. No relay clicks either, it just goes away, and then intermittently
comes back, with no fanfare that would possibly point to where the problem could be..
This one has me stumped.. There are no leaking, or bulging electrolytics on the boards..
If that does happen to be the problem... oh dear me.. of the 1,215-1/2 caps in the radio; which one
would it be ??? It acts like the Receive RF stage just loses power, and shuts off, then power 
comes back, and so does the recieve.. Lots of SMD stuff in this rig too.. I will mention this..
I have not looked in the service manual to see if there is a point where I can measure the 
voltage going to the RF board and watch it to see what happens during the on and off's..
Since I just now thought of that while typing this, I'll pursue that avenue and be looking for 
any replies and suggestions of what might be going on.. This is the only rig I have, and
no money to buy another one, so I do hope that I can fix the problem..
Thanks for your time, and for reading this.. any replies will be greatly appreciated..
Reply to me direct if you wish, so as to not clutter up the list..

73 :

Andy - KU4XR