[ICOM] IC-PW1 - Problem - any advice or ideas?

[Tony Visco]

Adam,

Thanks for the additional insight.  What I have noticed is as the tuner is
working it apparently increases power as the tuner completes its work.  I
assumed that this was a normal process in completing the auto tuning
procedure.  Well anyway thanks for all the professional advice.

Tony

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Adam Farson
Sent: Monday, November 06, 2006 3:15 PM
To: 'ICOM Reflector'
Subject: RE: [ICOM] IC-PW1 - Problem - any advice or ideas?

Ken, Tony,

The alarm indication you are seeing indicates PA imbalance. One or more of
the 4 PA modules is damaged. A trip to the Bellevue service centre is
definitely indicated, although a skilled owner could do the repair himself.

This failure mode can occur if one transmits whilst the PW-1 is executing an
auto-tuning or band-change cycle. It is imperative to wait until all LED's
are steadily lit before transmitting, even if that "rare one" gets away as a
consequence.

If the PW-1 is driven before all the RF relays in the low-pass filter box
and ATU have settled down, a blast of RF energy will hit the relay coils and
burn them up, as well as destroying the relay driver IC's. This, in turn,
will lead to the failure of one or more PA modules.

Cascading auto-tuners must also be avoided. The exciter's autotuner must be
off when driving the PW-1. In any event, as the PW-1 has a flat 50-ohm
resistive input, the exciter's ATU is not required. 

When using an external tuner, the PW-1 auto-tuner must be off. The external
tuner should be tuned up on exciter power alone (< 10W), with the PW-1 in
standby. The drive level should be kept to a minimum in this configuration,
or R7 on the Splitter board will burn up.

The ALC must be correctly calibrated (user manual, p. 11) before putting the
PW-1 into operation. This is not negotiable.

I would recommend that you join the Yahoo! PW-1 group. I am one of the
moderators; we neutralise all spammers.

http://groups.yahoo.com/group/ic-pw1/

Hope this is helpful.

Cheers for now, 73,
Adam VA7OJ/AB4OJ

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Tony Visco
Sent: 06 November 2006 03:20
To: 'ICOM Reflector'
Subject: RE: [ICOM] IC-PW1 - Problem - any advice or ideas?

Ken,

I am sure Adam will provide all the details but you can bet that Bellevue
will be happy to see you.  There are 4 Amp circuits and one or more have
been damaged in some way.  

One way is the transceiver tuner on along with the PW-1 tuner - a no no.
I had the same problem about a year ago and it did cost about $470.

I still think the PW-1 is a great amp married to my 756-Pro III because
switching bands is such a snap.  Once in a while the tuner takes a little
time to find itself but what a combination.

Tony W3EW 

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Ken Kinyon
Sent: Sunday, November 05, 2006 10:47 AM
To: Icom at mailman.qth.net
Subject: [ICOM] IC-PW1 - Problem - any advice or ideas?

This morning, My PW-1 developed a problem.
I noticed that there was no output power.
The amp protect light was lit red.  The auto light was blinking green. I
reduced the input power to fully low and powered off the amp.  Finding
nothing wrong with the antenna (SWR is 1.1:1) or any wiring I then switched
to a dummy load.
SWR on Dummy load is 1:1.  I then reset the amp protect button and turned
amp on and attempted to transmit. As soon as I advanced the drive to about
10 watts, the amp protect light changed to red and the auto light started to
blink again, this time a hot smell, but no visible smoke came from the
amplifier.  I am assuming that it is off to Bellevue with the amp, but would
like to listen to any ideas first.
Thanks,
Ken W7TS



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