Re: [amsat-bb] Icom 910 and Mirage preamp

["KC6UQH" <kc6uqh@xxxxxxx>]

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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