Re: hp 2100A housing wanted

Paul Birkel



Here’s what I read in your list, reordered and annotated:


HP 02100-60014            B-1144-22         Slot A1 Timing and Control

HP 02100-80002            C-1044-22         Slot A2 ROM Control (presume actually 60002)

HP 02100-60004            D-1144-22         Slot A3 Microinstruction Decoder 1

HP 02100-60112            A-1402-22         Slot A4 Microinstruction Decoder 2

HP 02100-60001            A-1051-22         Slot A5 Arithmetic Logic

HP 02100-60003            B-1289-22         Slot A6 Instruction Register Decoder

HP 02155-60003            A-1201-22         Slot A6 Instruction Register Decoder (presume actually 02100)

HP 02100-60024            C-1215-22         Slot A7 I/O Control

HP 02100-600?7            C-1216-22         Slot A8 I/O Control Buffer

HP 12895-60001            B-1144-22         Slot A9 Direct Memory Access


Assuming that my corrections for your typos are correct then you have a complete set of CPU PCAs (Printed Circuit Assemblies, HP-speak) with one spare, plus the optional DMA.  Despite the presence of top-finger connectors there are no over-the-top cables involved in the standard CPU configuration.


HP 02100-60012            B-1410-22         Slot A101          X-Y Driver Switch

HP 02100-60012            B-1152-22         Slot A101          X-Y Driver Switch

Missing Core Stack /Sense Amplifier in slot A102

Missing Core Stack /Sense Amplifier in slot A103

HP 02100-60012            B-1410-22         Slot A104          X-Y Driver Switch

HP 02100-60012            B-1152-22         Slot A104          X-Y Driver Switch

HP 02100-80009            A-1049-22         Slot A105          Inhibit Driver (presume actually 60009)

HP 02100-80009            A-1049-22         Slot A105          Inhibit Driver (presume actually 60009)

HP 02100-60010            A-1046-22         Slot A106          Inhibit Driver Load

HP 02100-60011            D-1??2-22         Slot A107          Data Control


Assuming that my corrections for your typos are correct then you have enough PCAs (plus some spares) to support two core stacks, but no core stacks listed.  Those would be either 5060-8324 or 5060-8331.  You’ll need the over-the-top hard-connector-pair 02100-60052 and/or 02100-60054 to link the applicable X-Y Driver Switch to the adjacent Core Stack.  You’ll also need a pair of multi-connector over-the-top cables that bridge A105, A106, and A107 in addition to the backplane.  A minimum configuration would populate slots A103 through A107 plus require three OTT connections/cables.  Note that the photo at has removed these OTT cables (along with the cover of the power supply) for “visual effect”.  There are also some PCAs missing and others misplaced; don’t know what the photographer was thinking!


I presume that your “wiring harness” includes both backplanes – the long one is for the CPU and I/O subsystems; the adjacent short one is for the Memory subsystem.  Do you have the associated card cages?  Those would include the slot-labels that I’ve indicated above.


You have two I/O PCAs:


HP 02748-60034            A-12009-22        Paper Tape Reader

HP 02758-600?4            A-835-22           Paper Tape Reader-Reroller


Assuming that you want a little useful I/O besides your surrogate front panel I suggest that you watch eBay for the following:


HP 12966          Buffered Asynchronous Data Communications Interface (BACI)


HP 12531          Buffered Teleprinter Interface (HS Terminal)


HP 12565          Microcircuit Interface (GND True In/Out)


HP 12566          Microcircuit Interface (+ True In/Out)


HP 02100-60060 Terminator (TERM)


You might be able to manage without a TERM PCA if you only have two I/O PCAs installed, although I believe that HP recommended it even in a minimal configuration.


These PCAs are all pretty well documented at the HP Museum (all hail!).  They all show up on eBay from time-to-time.  There was a thread regarding the Microcircuit Interface here earlier in February.


You’ll also need to find/build I/O cables for these.


Suggest that you look into some interfacing in order to run available paper-tape software.  See: “Paper-Tape Emulator” “USB Disk Interface for HP21xx Minicomputers”


You can probably use the 02748 PCA instead of a 12565 or 12566 Microcircuit Interface PCA to achieve parallel _input_, but I suspect that you’ll want _output_ as well :->.


And then think about bringing up HP-IPL/OS (


Good luck!


From: [] On Behalf Of ChrisBeee via
Sent: Saturday, February 27, 2021 5:34 PM
Subject: Re: [VintHPcom] hp 2100A housing wanted


...sorry, I was typing too quickly, the 12100... are actually all 02100-xxxxx boards...

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