Mystery HP 1000 board

Paul Birkel pbirkel at
Thu Jun 16 00:44:17 CDT 2016

See:  Figure 4  

Shows some of those other parts as well in the block diagram.  Uses a "HP 21MX K-Series Computer".

Model 5420A Digital Signal Analyzer.

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of CuriousMarc
Sent: Thursday, June 16, 2016 1:16 AM
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: Mystery HP 1000 board

You beat me! You got one hit. How did you search for that? I come up dry...

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of Pete Lancashire
Sent: Wednesday, June 15, 2016 8:50 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Mystery HP 1000 board

Well there are 20 bits of ALU ....

And this guy has one and some other boards

  HP 5443
  05443-60031  MIOB Interface
  05443-60050 Booster Microcode
  05443-60057 C (13803F?)
  05443-60071 A (22803F)

NO Connection with the site/person/etc .. just passing it on

On Wed, Jun 15, 2016 at 8:00 PM, Jay West <jwest at> wrote:

> I have one of those boards. You sent me an email about it and I 
> replied a week ago :)
> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at] On Behalf Of 
> CuriousMarc
> Sent: Wednesday, June 15, 2016 9:49 PM
> To: cctalk at
> Subject: Mystery HP 1000 board
> Can anyone identify this HP board (see link to pictures)?
> It was at under the main board of a newly acquired HP 1000-E, next to 
> the firmware board. It says HP 54427-60050 Booster Microcode. It has 5 
> bitslice SN 74S181 chips at the back. So I surmise maybe it's a late 
> ALU booster upgrade?
> Marc

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