replacement transformer wanted for IMSAI power supply

From: Richard Erlacher <edick_at_idcomm.com>
Date: Mon May 10 09:59:33 1999

What are the physical dimensions of this transformer, Eric? I've been
rooting around in that portion of the basement which has such things.
Perhaps I have a potential drop-in replacement. I know I still have a
couple of the transformmers from the ALTAIR, though I don't know which one.
You may recall I bought a load of a couple of hundred back in the late
'70's. I've got a number of different transformers that might serve.

Dick
-----Original Message-----
From: Eric Smith <eric_at_brouhaha.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Monday, May 10, 1999 2:14 AM
Subject: Re: replacement transformer wanted for IMSAI power supply


>Dave Dameron <ddameron_at_earthlink.net> replied about my IMSAI PSU woes:
>> If the voltages checked out without a load, look for a very
>> good short somewhere.
>
>The incoming AC was measured at 120.0 VAC. The primary has taps for
>nominal, -10%, and +10% input. When I received it, it was apparently set
>for -10%. I say apparently because the transformer doesn't match the one
>in the IMSAI manual. The no-load DC voltages are expected to run high, but
>these were even higher: 25V vs. 18V, 11V vs. 8V. I switched it to the +10%
>tap, and now under some load (CPU, one memory card, front panel) the DC
>voltages are very close to the nominal values. So I suppose this could be
>indicative of shorted turns in the primary.
>
>> The 5 Amp line fuse didn't blow?
>
>Nope. But the transformer emitted a foul stench after a few minutes. It
>wasn't hot enough to be painful to touch, but it was close.
Received on Mon May 10 1999 - 09:59:33 BST