[ICOM] Re: Need Help w/PW-1 Problem

[Anthony R Gargano N2SS]

Harry, with regard to the ALC adjustment, just a few watts of drive makes 
the amp kick out so it is not possible to make the adjustment.

Johnny, All the voltages seem to be there, so I think the PS is OK.

When the amp kicks out besides the AMP/PROTECT led turning red, the AUTO 
led blinks. According to the instruction manual a blinking AUTO led fault 
indicates the "power level of the 4 PA units becomes unbalanced". That 
leads me to believe I may have lost one of the output devices. The RF 
output stage is comprised of 4 boards, each with a pair of MRF150 devices 
and the output of each board is fed into a combiner via an RCA plug. Any 
PW-1 owners have experience in individually measuring the RF output of each 
of the PA boards? If so, what did you use to do it with? Thanks, Tony N2SS

>Date: Sat, 03 Jul 2004 22:58:06 -0400
>To: icom at mailman.qth.net
>From: Anthony R Gargano N2SS <n2ss at n2ss.com>
>Subject: Need Help w/PW-1 Problem
>
>I have an early serial number, 1138, PW-1. The amp has worked fine up 
>until now. This evening I started to get an "Amp/Protect" fault on every 
>band - 160 thru 6 meters. I have connected the amp to a dummy load, done a 
>CPU reset and a reinitialization - all to no avail.
>
>I drive the amp with a 756 PROII and have been using this particular 
>combination for several years. If I reduce the drive to minimum (RF Power 
>control fully CCW), the amp keys and does not fault but as soon as I begin 
>to increase the drive, it kicks out and the Amp Protect led turns from 
>green to red. The 45V HV line to the PA stages is fine. I would really 
>appreciate any thoughts or suggestions. Thanks, Tony N2SS