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Microvax II

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PG31

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May 31, 2011
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Sefton, Meresyside, England
I have two of M7606 and four of M7608 cards. They are the Microvax II CPU and 4MB memory cards. I would like to build a Microvax II in a BA23. I don't have the bulkhead for the serial console and baud rate switch etc. Has anyone on here had a go at building a bulkhead or have a spare that they would sell/swap? I've checked the usual auction sites and none seem to come up or only come up with the CPU card and are quite expensive.
Thanks.
 
Those MicroVAX BA23/BA123 bulkhead panels do show up on eBay from time to time, at least in the US, but they can be hard to search for depending on how the seller describes them. I couldn't find any on eBay today with a quick search. I have seen them sometimes around the $20-30 range in the past, and sometimes a lot higher, and sometimes people are giving them away. Sometimes the battery has leaked and corroded and ruined everything.

I probably have more of them than I do BA23/BA123 boxes, but less of them than I have KA630/KA650/KA655 CPU board sets.

It shouldn't take too much to wire up some cables for the minimal functionality instead of trying to build a full functionality equivalent.

http://www.bitsavers.org/pdf/dec/vax/630/MP02071_630QB_Mar85.pdf
Page 85, Function Selection & SLU Module schematic

It should be simple to wire up a cable between the 10-pin J3 connector and a DB9 or DB25 serial port connector.

If you don't need the LED status display then on the 20-pin J2 connector you only need to ground the appropriate pins of the 3 baud rate select signals, and optionally ground the halt enable signal. You could also try to wire in a battery, though I live without batteries in mine so I don't have to worry about them leaking.

-Glen
 
Hi PG31,

Not sure if it's quite relevant but I have a PDP-11 in a BA23. Like you I don't have the rear panel with baud rate switches and LED display but I have brought out the two serial ports on the edge connector to a pair of 9-way D-type connectors. The baud rates for the ports can be set by jumpers on the board as well as on the rear panel so I've gone that way. I don't have the LED display at all. The machine works fine.

I have made myself a plastic cover for the back with the 9-way connector cut-outs and it all works fine.


Cheers,

Andy.
 
I've managed to get my hands on a bulkhead and I'm waiting for it to arrive from the USA.
I have a BA23 pedestal mount cab, my intention is slot 1 KA630, slot 2 and 3 MS630. I will follow these with my Emulex UC08 and then a DELQA. Is this a valid config? (maybe the DELQA before the UC08?)
 
You will want the RAM in slots 1 and 2, with the CPU in slot 3. I had a m7606 uvax 2 in a BA123, and that's how it was configured before I replaced it with my 11/93.

You should have the Ethernet as slot 4.
 
Yep, PMI plus. You will need the over the top ribbon cable connector as well, with 3 plugs (or more). Also, in the ba23 chassis, slots 1-3 are Q22/cd, slots four through eight are Q22/Q22 serpentine. Assuming the emulex uc08 is a dual height card, you will want the Ethernet in slot 4 AB (left side), with the uc08 in slot 4 CD (right side).
 
Last edited:
Roe said:
You will want the RAM in slots 1 and 2, with the CPU in slot 3. I had a m7606 uvax 2 in a BA123, and that's how it was configured before I replaced it with my 11/93.

You should have the Ethernet as slot 4.
Click to expand...

As far as I know in a BA23 or BA123 you only put M8637 MSV11-J PMI memory ahead of an M8190 KDJ11-B 11/73 CPU. With a M7606 KA630, M7620 KA650, or M7625 KA655 MicroVAX CPUs you put them in slot 1 ahead of the MS630 or MS650 memory in slot 2 or slots 2 and 3 (or slots 2, 3, and 4 in a BA123).

MicroVAX Maintenance Guide
http://www.bitsavers.org/pdf/dec/vax/630/AZ-GM3AA-MN_uVAXII_Maint_Oct85.pdf
See page 5-3, recommended module sequence.
 
I stand corrected, cpu goes in slot 1. Surprisingly, everything worked in my ba123 with the cpu in slot 3. (Opens mouth, removes foot :)
 
Bulkhead arrived today and I can boot my MicroVAX to the >>> prompt. I have an RQDX3 with a spare RD32, An Emulex UC08 with several SCSI disks. An RX50 drive and a TK50 and controller. I also have an OpenVMS iso image for VAX.
How can I get VMS onto this machine?
 
The easiest option would be to install OpenVMS from a SCSI CD-ROM drive attached to the Emulex UC08. I haven't done this myself with a UC08 since I have never had one but have done it several time with a CMD CQD-220. I think you need to find a SCSI CD-ROM drive that can be jumpered for 512-byte sectors. I've had good luck with a variety of older Plextor SCSI drives picked up cheap at a local PC recycler.

You could also do the install on a SIMH disk of the same size as a physical disk you want to use and after you get it all setup as you like then 'dd' the SIMH disk image to your physical disk. Doing the install using SIMH should probably go a lot quicker than on the real hardware.
 
If you already have a working DEC RRD4x SCSI drive you should be good to go after you burn a copy of the install disc. It might take some fiddling with the UC08 configuration utility to get it configured correctly with a disk and the CD-ROM drive. I can't help with that but others here can.

I would probably keep things simple and just start with CPU, RAM, and the UC08, and skip the RQDX3 and TQK50 for now.
 
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