[ICOM] Help. Please with IC-735 No transmit

[Al Waschka]

Thanks for looking!
 
I have an Icom 735 that I have used for several years with no problem with an AH-2 antenna tuner.  Recently I got some reports of distorted transmit audio, then the tuner started giving an intermittent no-tune.  If I switched the unit manually to FM before tuning, it seemed to work OK.  Now it will not tune at all.  I think I have diagnosed the no-tune problem to be a no transmit RF problem.  If I disconnect the tuner and connect the radio to a 50 ohm dummy load I get no power out in any mode on any band. I would think this is a PA problem except if I put a nearby receiver on the frequency I hear nothing.  If the PA was bad I would think I'd still get a weak signal on a local receiver.  
 
Through all this, the receiver seems to work fine.  I read the TSB on the VCO trim caps and located them on the schematic.  They are in the circuit in both transmit and receive, so I would think there would be some symptoms on receive and there are none.  
 
Has anyone seen anything like this?  I guess I'll be starting with the BFO oscillator and following the transmit signal all the way through the radio.  My best guess at this point is one of the switching diodes has failed.
 
Thanks,
 
Al K5TAN