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Re: Icom 910 and Mirage preamp



There are several  silicon sealants that will work, but they must state in
the directions, neutral cure, or for electrical assemblies and not "releases
citric acid when curing".
Furuno, A well known Marine Electronic Equipment Manufacture put out a
directive on this issue in 1987.

Art, KC6UQH
---- Original Message -----
From: "W4UPD" <w4upd@bristor-assoc.com>
To: "William Fry" <billfry@personainternet.com>
Cc: "Amsat-bb@Amsat.Org" <amsat-bb@AMSAT.Org>
Sent: Sunday, May 22, 2005 6:10 AM
Subject: Re: [amsat-bb] Icom 910 and Mirage preamp


> Not sure whether you received an answer to this or not, but I recently
> had to rebuild one of my preamps here. I found that if you seal it with
> the wrong type of silicon or similar sealant you can still have problems
> as the sealant itself will vent a corrosive gas inside the unit and
> cause a fait amount of corrosion around the components. I found that if
> I use a car RTV sealant I have much better luck. If you checked to see
> if you actually have voltage on the coax to the preamp then then preamp
> will have to be removed and fixed/cleaned. Don't rely on the light
> coming on to assume you have power to the unit, check and make sure that
> it actually exists on the cable.
>
> I had one so bad that it had to be fixed and parts replaced. Others just
> needed cleaned well and it went back to working again due to the
> corrosion being across various connections. Cleaning it allowed it to
> work once again.
>
> William Fry wrote:
>
> > Hi all,
> >  All os a sudden my 145 mhz. Mirage preamp (mast mount) and very well
> > weatherprofed with commerical shrink tubbing etc. on connectors, won't
> > work, been up there about 10 years and never failed before. Its good
> > for 165 watts input, but never go much above 50 watts on the Icom most
> > times and below. If I put the pwr up to full on the icom the display
> > only reaches about 20 db, before it would go to 60db + (100 watts) .
> > The remote control led lights up, so pwr is on the coax. The 440
> > preamp (mirage) works well. When you push the button, the signal and
> > noise comes way up, no trouble to tell when its working. Coax is in
> > good shape and new drop lines (flexi coax)(rear of beams) installed
> > two years ago. Anyone have any ideas on what to check on. When I push
> > the remote switch for 145 mhz, there is no change what so ever in the
> > signal strenght. In the 440 mhz. the display bars increase and also
> > signal. Big job to take down from tower. Any help appreciated, thanks,
> > Bill.
> >
> > VO1OR
> ----
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