[ICOM] Icom PW-1 Fault - Protect Light On, Auto Light Flashing

[Bruce J. Howes]

Alright guys, thanks for the feedback, back to Icom she goes....I am a bit
disappointed, esp. if this is not warranty.
My 4KL has been humming along without incident for nearly 10 years.
I'll be sure to post the results on the board.

In regards to the antenna and power issue.
I know the antenna was in tune, I use balanced feedline and a proper
transmatch.
I do not rely on the internal tuner to bring the antenna into resonance, and
then I use the transmatch first and then allow the PW-1 tuner to take care
of any difference. 
I also know that the ALC was set on the lower/left side of the ALC marking,
should be ok there as well.

Failures do happen on new electronics, and that is what I hope for here.
Having a complete Icom shack, 703, 706, 765, 746, 4KL, PW-1, 970H, I'm
trusting Icom to do what they need to keep me a happy Icom customer.

I won't ask for a gift certificate for a 7800, but will settle for warranty
on the amp. :-)

73 Bruce W1UJR

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Vladimir V. Sidorov
Sent: Monday, January 02, 2006 10:30 AM
To: ICOM Reflector
Subject: Re: [ICOM] Icom PW-1 Fault - Protect Light On, Auto Light Flashing

Bruce,

After the symptomes like that I had to replace two pairs of MOSFETs some 350
bucks each pair plus work...
Most probably there was an excess power from an exciter or the ALC was not
properly adjusted. If so, first a resistor somewhere at the front end goes
off and you feel the smell, then the MOSFETs follow...

After the repair I first make sure ten times, the ALC is adjusted the way it
should be and I never pump the PA up to over 1KW, normally it's a bit lower.

Some 2 or 3 years after the repair and there is no problem anymore.
The PW-1 has been used with an IC-756 first, and now with IC-775 DSP.

Indeed, you need to look for specialists, the PW-1 is not an easy thing to
repair.

73,

Vladimir VE3IAE

--- 





> After working flawlessly for several months, the PW-1 developed a 
> problem this evening.
> While operating on 75 meters the "Protect" light came on the "Auto" 
> light is flashing.
> According to my manual this indicates that the "Power level of the 4 
> PA units becomes unbalanced".
> Powering off the unit and attempting to transmit again gives the same 
> result.
>
> Common faults, or suggestions of where to look?
> I noted a burning smell, much like one gets from a charred resistor.
> A quick look under the hood does not revel any immediate faults, but 
> the smell is still present.
>
> Should this not be a straightforward field repair, the next question 
> is where to send the unit.
> I typically send items back to Icom and have always had good luck, but 
> wonder if the group has another suggestion of someone on the east coast?
>
> Tnx,
> Bruce W1UJR
>
>
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net Icom 
> Users Net: Sundays, 1700Z, 14.316 MHz Icom FAQ: 
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----
Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net Icom Users
Net: Sundays, 1700Z, 14.316 MHz Icom FAQ: http://www.qsl.net/icom/