[Icom] IC-761 s-meter bulb

[George, W5YR]

Well, Paul, in my case there was no rotator involved so the problem was
strictly internal to the 765. Seems that there was a serious timing problem
in the transition from receive to transmit and back again and that largely
caused the pre-driver transistor to fail.

I believe that you had yet another (and very insidious!) cause for the
transistor to fail. Glad you caught it and can warn others. 

73/72/oo, George W5YR - the Yellow Rose of Texas         
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe   
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121  Kachina 505 DSP  #91900556  Icom IC-765 #02437


Paul Playford wrote:
> 
> Ah yes, this is the transistor that kept blowing in my IC-765.  Turned out
> to be poor ground connection between my station ground and tower ground.
> Every time I turned my rotator (T2X) the voltage on the wiper of the
> direction indicator potentiometer (in the rotator housing) came down the
> center conductor of the antenna feed line and wiped the driver transistor
> out.
> 
> I know this transistor was a very common failure in the 765 and I cannot
> help but wonder how many of these failures occured because of Ham M rotator
> housings not being bonded to the station (radio) ground.
> 
> In addition to bonding my tower ground to the station ground I also
> disconnected the safety (green wire) ground inside the rotator control box.
> This is a no, no, but it works for me.