10 May
1999
10 May
'99
2:59 a.m.
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(a)brouhaha.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Monday, May 10, 1999 2:14 AM
Subject: Re: replacement transformer wanted for IMSAI power supply
Dave Dameron <ddameron(a)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.