10 May
1999
10 May
'99
5:59 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. 
10 May
10 May
6:59 a.m.
>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.
A good replacement would be found as a transformer used in an TEI,
Intergrand or Compuporo box. They will be of the right size, power and
configuration or very close.
Allison
8:12 a.m.
On Mon, 10 May 1999 allisonp(a)world.std.com wrote:
I'd watch out for the TEI units... As I recall they used a ferro-resonant
transformer which can offer some rude surprises if not handled carefully.
The CompuPro boxes (later ones at least) did the same I believe, but I'd
have to pull the top off of one of mine to verify.
It would be a workable solution, if not historically accurate. B^}
-jim
---
jimw(a)computergarage.org
The Computer Garage - http://www.computergarage.org
Computer Garage Fax - (503) 646-0174
>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.
A good replacement would be found as a transformer used in an TEI,
Intergrand or Compuporo box. They will be of the right size, power and
configuration or very close. >> Coming soon to www.computergarage.org - the
CBBS/NW on-line archives
>> Coming to VCF III (2-3 October 1999) - CBBS/NW
live!
12:58 p.m.
I know where there's a empty Compupro box in a scrap yard. Let me know if
you want me to see about grabbing it for the transformer.
Joe
At 11:59 AM 5/10/99 -0400, you wrote:
>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.
A good replacement would be found as a transformer used in an TEI,
Intergrand or Compuporo box. They will be of the right size, power and
configuration or very close.
Allison
9200
days inactive
9200
days old
3 comments
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participants (4)
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allisonp＠world.std.com -
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jimw＠agora.rdrop.com -
rigdonj＠intellistar.net