[ICOM] 75 PRO III Smoked!

[Stephen Budensiek]

Jay,
   Don't know about the Pro 3, but I have the Pro.   They have a
problem with the drivers going.  Mine took the chip resistors in
series with the drivers, and the driver that shorted.   Icom said this
is realated to static electricity (lightening in the area, within a
mile or two with antenna connected)  Wonder if the same problem is in
the Pro 3?   Haven't seen a new version Pro 3, so can't answer your
question.   Wonder what s/n range this is in?   I replaced the drivers
and chip resistors, all has worked ok since.

73's de Stephen, K0SD

**********************************

On Mon, Feb 20, 2012 at 7:21 PM,  <jkolin at optonline.net> wrote:
> I have a late production unit. It has the newer PA Board using MOSFETS as drivers and finals.
>
> 3 Days ago I was checking SWR on a new ant. 2/1. Key down w/100W for about 10 seconds. After a few SWR measurements power dropped to 5 W max. Then I could not go into transmit mode. After about a minute in receive mode, smoke billowed out of the rear panel from the PA compartment.
>
> Removed top covers and found 3 burned SMD resistors. R38, R39 & R40.  4.7 ohm. All 3 are in parallel.
>
> Anyone have problems with this newer PA board? I have not been able to find parts layout drawing that applies to this new PA board.
>
> Thanks for all your thoughts.
>
> Jay....
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