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

[Vladimir V. Sidorov]

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
>
>
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