[Yaesu] Yaesu FT857 6m oscillation fix details wanted

[Paul]

My IC-756PROII has a similar problem.  I have replaced all of the PIN diodes 
in the antenna and band pass filter circuits and the oscillation went away, 
but then came back and only on 6 meters.  My current work around is to 
enable the 6dB attenuator in the receiver and that results in no 
oscillation.

Obviously a leaky PIN diode but I have never been able to identify the 
guilty one.

de Paul, W8AEF

-----Original Message----- 
From: John Geiger
Sent: Friday, July 12, 2013 5:41 PM
To: yaesu at mailman.qth.net ; yaesu at contesting.com
Subject: [Yaesu] Yaesu FT857 6m oscillation fix details wanted

I have an early model Yaesu FT857 that has now developed the dreaded 6 meter
oscillation problem. It had the poor audio on 6m for about 5 weeks after I
got
it, then it started going into oscillation part of the time on 6m, now it
does
it all of the time. This is not the self oscillation that occurs when the
circuit board screws are loose-with those, you see power immediately upon
keying
the mic.