[ICOM] 75 PRO III Smoked!

[Joe Dube]

I just had my finals replaced on my PRO lll  . Started talking and the power 
began to fall of to nothing. It is a pretty late model as well. Guess there 
is a problem beginning to pop up.

Joe Dube K4TR
K4TR Antenna Mfg & Sales
www.k4tr.com
352-232-0281



----- Original Message ----- 
From: <jkolin at optonline.net>
To: <icom at mailman.qth.net>
Sent: Monday, February 20, 2012 7:21 PM
Subject: [ICOM] 75 PRO III Smoked!


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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