Compact QBus Systems (Was re: Los Angeles: Commodore PET 8032's...)

From: Allison J Parent <allisonp_at_world.std.com>
Date: Sun Mar 12 16:10:51 2000

 ALSO, the unit is VERY under powered. The DEC specs say only 16 amps
<> on the 5 volts which also includes the video interface and the AVO optio
<> if you want a full screen 132 character display. I suggest that if you u
<> a Quad 11/73 with the RQDX3, you are probably OK. But not much else.
<
<I no longer need 132 columns to be fulfilled, so the AVO can be omitted.

The AVO option really doesn't draw that much power and in the overall
scheme it's far from enough.

<I'd be attempting a dual 11/73, NS 256Kb, Sigma DLV11, and CMD 220 TM SCSI.
<that doesn't work, I'll try taking out the DL and memory and using an MXV11
<though I recall those only have 32Kb or 128kb, which would make it pretty
<difficult to run RSTS/E.

That should work but the disks will have to be in their own box with their
own power. There isn't enough power there for most disks.

<Good advice for _any_ qbus system. I learned that the hard way, running 4-
<SCSI devices (2 sets mirrored) in a BA23 chassis, and wondering about the
<mysterious lockups. External drive chassis eliminated those, though cable
<lengths became very critical.

I'd limit that comment to ba23. My BA11S 11/73 has a full bus and powers
floppy and two RD52s off a custom harness.

<What I'm really hoping for is what was I think called a BA23-SE or BA11-SE
<'twas a desktop 4-slot enclosure, maybe even 4x2?

You thinking of BA11-VA, dual width by four slots, 4"x13x12 roughly.
That would work but you still need an external disk box. I have several
of those with 11/2, 11/23 cpus. The larger of them is 11/23, 256k, dlv11j,
MRV11B(tu58 boot).

There never was a ba23SE that small as the BA23 was one size (about 5
different backplane and front button combos.

Allison
Received on Sun Mar 12 2000 - 16:10:51 GMT