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BA-23 Chassis for PDP-11/MicroVAX QBUS

E

edaustin

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Mar 27, 2024
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So found a source for a BA-23 chassis + PSU working from a local(ish) seller

They are asking $700... (500 pounds UK + postage) next day delivery (which is nice).

I am desperate.... as these are incredibly hard to get hold of... and I can then QBUS card 'it up' to a decent PDP-11 standard quite cheaply (such as an 11/23).

Finally then will have my (Micro)PDP-11 after years....

Question is, is it a fair price? I might have to buy anyhow as it could literally take years to get one otherwise in the UK, still would like to know peoples opinions.
 
It seems a little expensive, you can get the raw backplane for a lot less....

www.ebay.co.uk

DEC Digital Equipment Corp H9278-A backplane chipped PDP11 Micro Q22 Buss 8 Quad | eBay

It is a DEC model # H9278- A backplane as pictured. These were pulled from a working system years ago. The chip will not affect its function or work fine. These are QBuss, 22bit, 8 quad slots. RX01 M7846 UNIBUS KDF11 CPU M8186 MMU & FP Chip Q-Bus.
www.ebay.co.uk

but then thats everything....
 
Thanks, yes I saw these and considered that idea, would need to import from US so add 30%.... crazy import duties/tax here in UK, and returns wouldn't be simple, and I'd lose a lot.

However I'd still need a case (so the QBUS cards could be mounted securely) and PSU and cables, and therefore decided that it would be far easier to find a BA-23 and only then need to worry about buying and testing QBUS cards.

Initially would just get a cheap CPU card like an 11/03, some memory and a serial card. After that could get a Disk controller (likely a more expensive QBUS SCSI card). Start with something like RT-11.

I remember back in 1995 at University they dumped end-of-life BA-23 MicroPDP's and MicroVAX II's on the skip.... I even had one back then hauled away from the trash... should have got all twenty or so and put them in my parents basement for thirty years ))))
 
g4ugm said:
Sadly I just sent an 11/23 card off to Germany but the recipient already had a BA-23....
Click to expand...
Oh well(

I'll get that BA-23 I think as its not as if I can hope one pops up on eBay and if it did, bidding would get ferocious.

I think I saw a couple of VAX and a larger PDP11 (or two) and spares six months ago on ebay (looked like a huge pile of broken washing machines outside somebody's house from afar) go for £3000.... around $4000.

There again I saw an LSI-11 QBUS board barely make £50 recently (I should have bid).
 
If you are in the UK, lookup one of my posts in the market place. I have dual height 11/73 CPU, memory and DEQNA Ethernet cards going for free (but pickup only and a donation to charity).

No complete systems left though (all spoken for).

It does sound expensive but, if you are desperate...

Dave
 
Thanks! Pity I am in Scotland!

I am just about to pull the trigger and purchase the BA-23 though - I am not sure if I also need a control panel? I expect a MicroPDP11 control panel will also not be cheap.

As I understand for checking the backplane/power etc I'll just need a LSI/PDP QBUS CPU and a QBUS serial card (and maybe some RAM). I did hear some cards actually have limited memory+serial port on them so could all be one (dual) card but haven't found which models yet (if any).
 
The microPDP11 control panel usually just has a couple of LEDs on the front and 2, 4 or 6 buttons for controlling the disk drives etc. (depending upon which model you are purchasing).

There are all sorts of options for PDP-11 CPUs, so it is all a matter of what is available and what your preference is.

Of course, there are also third-party CPUs (e.g. Mentec).

Dave
 
edaustin said:
I did hear some cards actually have limited memory+serial port on them so could all be one (dual) card but haven't found which models yet (if any).
Click to expand...
You're probably thinking of the MXV11-B (M7195) Multi-function Option Module, which includes 128KB RAM, two ASYNC I/O, RTC, and a pair of 28-pin ROM sockets.

http://gunkies.org/wiki/MXV11-B_Multifunction_Option_Module
 
edaustin said:
Thanks! Pity I am in Scotland!

I am just about to pull the trigger and purchase the BA-23 though - I am not sure if I also need a control panel? I expect a MicroPDP11 control panel will also not be cheap.

As I understand for checking the backplane/power etc I'll just need a LSI/PDP QBUS CPU and a QBUS serial card (and maybe some RAM). I did hear some cards actually have limited memory+serial port on them so could all be one (dual) card but haven't found which models yet (if any).
Click to expand...
There is also a design for a panel on Github https://github.com/joelang/pdp-panel
no idea if its usefull, just remeber seeing it
 
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