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

[Julio]

There are some devices in the amp circuit that are supposed to protect the
PA units. I can't remember what Icom called them. Their failure gave the
same symptoms you are seeing. I had A simular situtation last year, due I
think to a bad Carolina Windom balun. I sent the amp to Icom for service.

Julio, W4HY


----- Original Message ----- 
From: "Anthony R Gargano N2SS" <n2ss at n2ss.com>
To: <icom at mailman.qth.net>
Sent: Sunday, July 04, 2004 1:05 AM
Subject: [ICOM] Re: Need Help w/PW-1 Problem


> 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
>
>
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