HP 9845B Model 100 PSU - looking for transformer

David Collins davidk.collins at bigpond.com
Sun Jul 24 05:22:37 CDT 2016

Martin, apologies for taking so long to reply to this - but I have one of
the transformers you are after.

It's in a defective 9845 power supply but I'm happy to extract it from the
supply if you still need one.

Send me an email at curator at hpmuseum.net and we can work out the details.


David Collins
Curator, HP Computer Museum

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of
Martin.Hepperle at dlr.de
Sent: Friday, 3 June 2016 11:26 PM
To: cctalk at classiccmp.org
Subject: HP 9845B Model 100 PSU - looking for transformer


I have got a 9845B which has a defective power supply unit - obviously a
very common problem.
After replacing the cracking epoxy capacitors I found that the mains
transformer seems to have a broken input winding.
Maybe someone tried to run it at 220V using the 110V input selector switch.

What I am now looking for is a defective PSU with a good transformer, resp.
just the transformer which may also have been used in other HP devices..

The transformer is located on the PSU mother board between the two large
It has the part number "9100-4037" and the date code "8-81"  printed on it.
It has two input windings and three output windings. Thus the output is a
bit different (one additional winding compared to Tony Duells schematics).

Maybe someone can help?


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