test-drb March 2018

test-drb@ccmp.vtda.org

158 participants
173 discussions

Somewhat random QBus backplane / chassis question

by derschjo＠gmail.com

Hi all -- I've got an 11/03 backplane here (designated as an "11/03 EA" originally but marked as "Model changed from EA to AA") inside a small chassis w/power supply, model "OH780-A."? (So it was at some point in its life the front-end to a VAX-11/780.)? As far as I can tell, it has a standard H9270 backplane (4-slot, quad width) in it. The chassis appears to work fine when I have an actual LSI-11 in there (I've been experimenting with an 11/23, but I do have an 11/03 boardset that works in it). What I want to do with the chassis is use it with a UNIBUS->QBus bridge I have, as a Qbus backplane for a SCSI controller (and maybe other things) for my VAX-11/750.? I have encountered an oddity in doing so, and I've looked at the documentation and I remain puzzled.? The oddity is this:? If I don't have an LSI-11 CPU board in place in the chassis, the power supply won't come up properly.? (The +5V appears to pulse, the kind of behavior I'd expect with a shorted or heavily loaded supply rail somewhere). Here's a basic rundown of what I've observed: - If I put an 11/23 or 11/03 CPU in, everything works fine. - Doesn't matter what slot the CPU's in either, as long as there's a CPU board somewhere in the thing, all's well. - Doesn't matter how heavily or lightly loaded the backplane is; I've tried it with just a QBus SCSI controller, I've tried it with the backplane stuffed full of boards. Since I want to use this as a simple QBus backplane, I don't want to have a CPU board in place.? I haven't seen this behavior before (but then, I can't recall trying to run a Qbus backplane without a CPU in it either).? I thought I knew QBus fairly well, so I assume I'm overlooking something obvious.? Or perhaps there is a fault here with the chassis, somehow.? I figure someone here will have the answer immediately and I'll slap my forehead... Thanks as always, Josh

6 years, 1 month

Remnants of local Commodore Users' Group being offered for free

by barythrin＠gmail.com

Whoever or whichever group does get it, i hope if they have any files or interesting info the rest of the clubs can help store. null

6 years, 1 month

R.I.P. Robert T. "Doc" Suding

by jnc＠mercury.lcs.mit.edu

> From: Al Kossow > The only place I ever saw an Apple I when it was for sale. Don't you wish you'd bought one - and kept it? :-) Noel

6 years, 1 month

Help with IC identification

by binarydinosaurs＠gmail.com

Hi folks, I'm looking for info on a few 8 pin DIPs that are in a cache battery module. They're marked thus: 4973 AK W79B 4965 AF W83A Anyone? I've not traced pinouts yet but maybe someone else's google-fu is better than mine today. Cheers, -- adrian/witchy Owner of Binary Dinosaurs, the UK's biggest home computer collection? t: @binarydinosaurs f: facebook.com/binarydinosaurs w: www.binarydinosaurs.co.uk

6 years, 1 month

DEC Field Guide > equivalent available for Data General?

by u.tagge＠gmx.de

Hi all, is there somewhere a list of DG modules which includes also 3rd party/OEM, ... like it is available for DEC? Would be good to know what the following is: 107-000621 02 107-000621 03/11 107-001632-00 107-0016320/02 107-000718-00 107-000181-04 107-000187-16 107-000187-15-30 AB020116-00 107-000621-03 107-001768-02 107-001768-03 107-0017680-1E 107-00053905 Zetaco SCZ-2 >500-453-00 K >500-542-00 K Many Greetings Ulrich

6 years, 1 month

Remnants of local Commodore Users' Group being offered for free

by cclist＠sydex.com

This is in Eugene, OR. I received the following email on the local Freecycle-type list: ---------------------------------------------------------------- I have all of the "Lane County Commodore Users Group" (LCCUG) inventory including (but not limited to) the following : Keyboards, one monitor, transformers, two disc players for 5 1/2 inch floppies, cassette tape player, games, a whole lot of instructions, dozens of empty discs, dozens of full discs, and much more. Plus a 25-plus pound lap top (SX-64) ! More than a regular car trunk can hold . Many items in original boxes. LCCUG is no longer exists. For a classic computer buff this would be a gold mine. It is amazing what this old computer was able to do - 30 years ago! 18th and Chambers area - Eugene. jimsav97405 at yahoo.com ------------------------------------------------------------------- I have nothing to do with this offer. FYI --Chuck

6 years, 1 month

FPGA implementations of DEC processors

by chd＠chdickman.com

There are enough pdp8 fpga that they have started to calll themselves YAPDP8FPGA. So what are the really good FPGA DEC processors? -chuck

6 years, 1 month

PDP8/e programmers consoles

by chd＠chdickman.com

So the PDP8/e used the KC8-EA programmers console which has incandescent indicator lamps and the PDP8/f used the KC8-FL programmers console which has LED indicator lamps. Why? The maintenance manual says that LEDs are more reliable. The operation is as far as I know the same. The LED version doesn't need the +8VDC supply, but that seems an advantage for it. I remember reading that the EAE had some revision dependencies with the console, so were there bus timing problems with the LED console that limited it to short buses? Maybe this changed over time, but it overlapped long enough for them to have both described in the maintenance manual and specific to the application. Another console question... Has anyone ever seen a PDP8/i style console for the PDP8/e? Looking at the way the PDP8/e console functions, it should be possible to time multiplex all the register to the data bus so they are all visible at once when the machine is halted. -chuck

6 years, 1 month

DEC RL cables, terminator, etc.

by useddec＠gmail.com

Several list members have asked me about RL cables, etc. I have finally gone through most of them. If anyone needs any parts, please contact me off list. Thanks, Paul

6 years, 1 month

AlphaServers

by john.h.blake＠gmail.com

I've got two, the first being an 3000/400 64mb with two 146 gb SCSI-320 drives running on converters, one with openBSD 6 and the other with openvms 8.4 running headless. I doubt I'll ever be able to find the monitor, much less the needed cables and keyboard/mouse to turn it into the desktop it was supposed to be, so I've got a color turbochannel framebuffer if anyone has any use for it. The second is an alphaserver ds10l with the 617mhz EV67 processor, 1.5 gb ram and a radeon video card on the sole pci port, which runs openvms 8.4 on one hard drive and the most recent available version of unsupported debian linux on the other (I think it's sid?) as a workstation. Nekochan.net is a fair resource for hobbyist knowledge, possibly the only place online where people are still futzing about with Tru64. comp.os.vms on usenet (or the info-vax email gateway) is where all of the latest news and deep tech discussion goes on. vcfed.org has a very healthy DEC forum too.

6 years, 1 month

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test-drb March 2018