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Looking at a PDP-11 Circuit Board

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cli...@gmail.com

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Aug 18, 2022, 7:57:07 AM8/18/22
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Looking at third-party PDP-11 circuit boards for sale on that auction site.
Is there a way to tell just from pictures if the board is QBUS or UNIBUS?

Johnny Billquist

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Aug 18, 2022, 3:24:14 PM8/18/22
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On 2022-08-18 13:57, cli...@gmail.com wrote:
> Looking at third-party PDP-11 circuit boards for sale on that auction site.
> Is there a way to tell just from pictures if the board is QBUS or UNIBUS?

It's tricky. I usually search for some identification printed on the
screen layer, or solder layer, that gives me some hints on names to
lookup which could tell what kind of systems used the board.

Just trying to look at traces or components is hard.

Johnny

P.Lj

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Aug 19, 2022, 6:00:58 AM8/19/22
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On Thursday, August 18, 2022 at 1:57:07 PM UTC+2, cli...@gmail.com wrote:
> Looking at third-party PDP-11 circuit boards for sale on that auction site.
> Is there a way to tell just from pictures if the board is QBUS or UNIBUS?

Are you looking for something specific?

^P
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cli...@gmail.com

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Aug 20, 2022, 7:44:44 AM8/20/22
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Data Systems Design A4430-4, 440 interface board, PDP-11, floppy/flexible disk
Not that interested in the particular board but it's not the first 3rd party board I've seen that didn't state which bus it was applicable to ...

Bill Gunshannon

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Aug 20, 2022, 8:11:41 AM8/20/22
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I have never had a PDP-11 module third-party or otherwise that had
anything on the board that said if it was QBUS or UNIBUS. Always
had to refer to the documentation for that.

bill

pbi...@gmail.com

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Aug 20, 2022, 9:18:31 AM8/20/22
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On Saturday, August 20, 2022 at 8:11:41 AM UTC-4, Bill Gunshannon wrote:
> I have never had a PDP-11 module third-party or otherwise that had
> anything on the board that said if it was QBUS or UNIBUS. Always
> had to refer to the documentation for that.
>
> bill

Not to mention that there are many, many modules that are neither -- they depend on a specific SU (system unit, "backplane") as part of a CPU, device controller, or other assembly that may-or-may-not have a bus interface at an "edge".

Being hex-height doesn't even rule out Qbus (thank you PDP-8/A :->).

pbi...@gmail.com

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Aug 20, 2022, 9:22:45 AM8/20/22
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On Saturday, August 20, 2022 at 9:18:31 AM UTC-4, pbi...@gmail.com wrote:
> Being hex-height doesn't even rule out Qbus (thank you PDP-8/A :->).

Grrr. Omnibus ...
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