Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!bionet!ames!killer!texbell!merch!cpe!hal6000!trsvax!uhclem
From: uhclem@trsvax.UUCP
Newsgroups: comp.sys.tandy
Subject: Re: Dying Model IV...can it be saved?
Message-ID: <193300120@trsvax>
Date: 31 Mar 89 17:09:00 GMT
References: <900@PSUVM>
Lines: 21
Nf-ID: #R:PSUVM:900:trsvax:193300120:000:946
Nf-From: trsvax.UUCP!uhclem    Mar 31 11:09:00 1989


<>
Sounds like your Model 4 has a "Tandy" power supply that is going bad.
At one point in the manufacturing life of the Model 4, someone at the factory
was using "Locktite" to secure a voltage-adgust pot.  Great, but the solvent
in that compound eventually eats the carbon out of the pot, causing wild
voltage fluctuations after the machine has been on a while.

Replace that power supply with a real "Aztec".  Both types are clearly marked,
but you can tell the difference by checking the switching transistor.   If it
is a TO3 can configuration, you have an Aztec.  If it is mounted on a
"stand-up" heatsink, you have a "Tandy" supply.   These supplies can be
obtained through National parts.  They were also used in external primary
hard disk drives.  (65watt)

<My opinion, and not that of my employer.>

					"Thank you, Uh Clem."
					Frank Durda IV @ <trsvax!uhclem>
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