test-drb August 2015

test-drb@ccmp.vtda.org

206 participants
257 discussions

by rob＠bitscience.ca

Hi Everyone, I?m looking for a scan or a printout of the contents of DEC fiche EP-M8436-MA-A. It?s referenced at the top of page 163 of http://bitsavers.trailing-edge.com/pdf/dec/pdp11/xxdp/fiche_200dpi/0254_ind…, and allegedly contains the details for M8436, M8437,M8439, and M8440 boards -- all of which were parts for the Decmate series of machines. If anyone has access to this (even if you have no way to read it), or has a pointer to where I might find it, I?d very much appreciate if you?d drop me a line. Thanks very much, Rob Ferguson

10 years, 1 month

More Manuals Plus Rescue

by tshoppa＠wmata.com

http://ascii.textfiles.com/archives/4711 Choice quote: "I am writing this from the car, sitting in the passenger seat with my shoes off. I have been standing for 12 hours. I've been giving introductions and tours and explanations and theories and everything else that comes when you put a bunch of strangers together with a single-minded purpose. They have been too good. Way better than anybody deserves in the way of volunteers. They have been helpful, kind, inquisitive, dedicated. They have come from miles around. Sometime around 11 a.m., it became very obvious that the 252 banker boxes we have bought or a laughable underestimation. We were going to need more. We are going to need much more, and we were going to need it now. I made a call to the Uline Company, and asked for the impossible: I wanted 8 pallets of boxes, delivered within the day. And within four hours, they arrived. To deliver 1052 banker boxes within 4 hours, combined with the cost of the boxes themselves, was $4000."

10 years, 1 month

test equipment / Re: Z80 / Z84C Swap (Doh!)

by jnc＠mercury.lcs.mit.edu

> From: Eric Smith > If a person has any reasonable business justification But a lot of the people here don't; they're purely hobbyists. So spending $1K on a piece of test equipment just isn't realistic for them. Having said that, I do see some DSO's on eBay for not much money (e.g. the little hand-held ones), and those might be a good alternative to a logic analyzer - I never used one, so I tend not to think of them. Noel

10 years, 1 month

QBUS boards on eBay checp

by jnc＠mercury.lcs.mit.edu

Some guy on eBay is selling a ton of QBUS boards, cheap: http://www.ebay.com/sch/computer_surpluscheap/m.html Includes deals such as 11/23 CPU's _with_ KTF11 and KEF11 for $30, 11/73 CPU's for $50, etc, etc. Anyone recognize those Motorola memory cards? Do we have documentatio for them? Noel

10 years, 1 month

More on manuals plus rescue

by jnc＠mercury.lcs.mit.edu

> From: Sean Caron > I have found that even fairly fine detail reproduces okay with a 300 > DPI scan ... there's no need in scanning with extraneous bit depth and > then you start to get people complaining about file sizes I have found that one can generally have one's cake, and eat it too: if I scan at 600dpi in black and white, and then use "CCITT Group 4" compression, the resulting images (of prints) are ~200KB per page. Is that small enough? :-) Noel

10 years, 1 month

RLV11 Debugging

by bensinc＠gmail.com

Now that I (hopefully) have my PDP 11/23 running (it passes CPU and memory tests, anyway), I've been messing with my RLV11 so I can use my RL02. For a first step, I'm trying to run the VRLBC0 diskless diagnostic to check the controller. I checked that the address and vector switches are set to the defaults according to he manual, and also verified them with a multimeter. The manual says the default vector address is 330, though the diagnostics default to 160. I tried it both ways with the same result, though I should be on 330. I'm not actually sure what "BR LEVEL" refers to, so I left that at the default. This is a PDP 11/23 with an H-9273 backplane. I have the M8186, M8067, M8043, then the two RLV11 boards, M8013 and M8014, then an M8012. Here's a sample run. It appears to start, but never does anything else. If I give it a bad address it does complain, so I think I have the switches correct. Does anyone know what I might try next? Thanks! .R VRLBC0 VRLBC0.BIC DRSSM-G2 CVRLB-C-0 RLV12 DISKLESS UNIT IS RLV12, RLV11, OR RL11 RSTRT ADR 145702 DR>START CHANGE HW (L) ? Y # UNITS (D) ? 1 UNIT 0 RLV12 (L) Y ? N RLV11 (L) Y ? Y CSR ADDRESS (O) 174400 ? VECTOR (O) 160 ? 330 BR LEVEL (O) 4 ? CHANGE SW (L) ? Y ERROR LIMIT FOR AUTO-DROP (D) 0 ? ALL REMAINING QUERIES ARE FOR OPTIONAL (MANUFACTURING) G5388 TEST-LOOP-MODULE SET-UP. USE <^Z> TO BYPASS. G5388 TLM INSTALLED (L) N ? N MMU AVAILABLE MEMORY SIZE 124 KW 18 BIT ADDRESSING -- Ben Sinclair ben at bensinclair.com

10 years, 1 month

Clearpoint DCME/Q4E configuration

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > DEC's memory boards never had any jumpers for PMI as such. Yes, and if you plug one of their PMI memory boards into a Q/Q backplane, it will emit magic smoke, too! :-) I think that's why this thing has the jumpers - to allow it to be used in a Q/Q backplane. It would, of course, only be normal (slower) QBUS memory, but at least one could use it there. However, I am unable to verify that hypothesis. (See below.) I looked at the jumpers along the edge in the C/D finger region, and a lot of them _do_ connect to pins used in the PMI bus. (Confusingly, a number connect to _other_ pins - I can see I have some detective work in front of me here!) However, that made it likely that the one that had jumpers on all those pins was configured for PMI use, so I rolled the dice, and tried plugging that board into a Q22/CD backplane, along with a KDJ11-B, and after a short bout of 'tired memory' (see my previous post), it did come up as a 4MB PMI memory! (Parity, though, not CRC - which might make sense, I guess - it has 148 memory chips on it, which is a multiple of 37, so 32 + byte parity, plus a spare chip, I would guess?) However, when I plugged the other one in - nada. No response at all; the boot PROM bitched about 'no memory at 0'. So I'm not sure _what_ that configuration is for. So then I took a flier (although the cards use the identical PCB, they do have a few minor differences in chip rev in a couple of the programmable chips), and put the jumper config from the working PMI card onto the other card, and it did 'sort of' come up as a PMI card. The boot PROM was complaining about "Memory CSR Error" (I'll have to investigate that further), _but_ the memory was shown (by the boot PROM 'map' command) as PMI, and my own memory-test program showed it was all working OK. Well, at least we have a jumper config that allows us to use these cards as PMI memory! Noel

10 years, 1 month

Tired memory?

by jnc＠mercury.lcs.mit.edu

So I've seen an odd phenomenon on some older QBUS memory boards I've got in. I can't understand it, and I'm wondering if anyone else has i) seen it, or ii) understand the cause. What happens is that the _first_ time I plug them in, some don't work - some (maybe all, sometimes) locations are mangling the data (I forget whether it's dropped or picked bits). Oh, and we're talking 4164's/41256's (or equivalents) here, for the actual devices. However, if I let them sit for a bit (powered off), and then try again, they work fine! I first experienced this phenomenon on some M8044's, which have on-board electrolytic filter caps, so I was guessing it was caused by some sort of noise caused by the caps not working, and after a little while powered on, the caps reformed, and things started to work. However, I just experienced the same phenomenon on a Clearpoint DCME/Q4E board - which doesn't have any electrolytic caps on it. So that can't be it. Anyone have any clue what's going on? (Oh, and of course, for others - if you buy and old memory board, and it doesn't work... don't immediately put it in the 'bad' pile, wait a bit, and try again. You might be seeing this.) Noel

10 years, 1 month

Help needed please re possible loss of a Burroughs B7800 CPU

by nw＠retroComputingTasmania.com

Hi Evan and others who might have been wondering, I managed to find out what happened to the Burroughs B7800 that was "under the stairs" at Monash university. The good news is that the interesting parts, namely the indicator panels, have been saved by the Monash Museum of Computing History. They also retrieved the VAX 11/780 that was there too, and it is now in storage.

10 years, 1 month

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test-drb August 2015