test-drb October 2016

test-drb@ccmp.vtda.org

203 participants
312 discussions

by jnc＠mercury.lcs.mit.edu

> From: Paul Koning > The trouble with chip resellers is that it's hard to know which ones are > legit, and which ones are in the fake chip business. I suspect that the network of major resellers would tend to keep out the riff-raff. (They don't need the aggro of dealing with the consequences.) > a 7400 instead of something more valuable. Which is why it's good that the DS8641's are going for little more than a buck; at that price point, there's only minimal benefit from faking them. Anyway, for any I get, random samples go straight into my tester board! "Trust, but verify!" :-) Noel

9 years

DEC bus transceivers

by shadoooo＠gmail.com

Hello, surely the old transceivers are the most compatible solution, however you still need to convert the voltages back and forth... Plus the solution is not the cheaper, and a little uncomfortable too, as you need to find these old chips, hoping not to buy fake chinese duplicates (it happened to me more time unfortunately). So I was searching a solution with modern components, but not using components too much specific and difficult to be found. As we need 3.3v logic, but able to work in 5v bus, I'm thinking about 5v tolerant standard logic as TI LVC or LVT. The problem is that there aren't open drain bus transceivers, but the problem could be solved simply using input-only and output-only components, connecting two in parallel but opposite direction on bidirectional pins. So identifying one or maybe two codes would be enough for all the components needed for the board. The idea of using bare transistors seems to me too much simple. Not that it couldn't work, but it would be almost impossible to satisfy all the specifications of the bus in this way... unless you use a more complex circuit with precise current sources and resistors to grant correct voltage biases, impedances and slew rates, which in the end is a logic integrated circuit. Andrea

9 years

DEC bus transceivers

by jnc＠mercury.lcs.mit.edu

> From: Guy Sotomayor > Secondary chip marke[t] (only reputable vendors). I'm a little more willing than Guy to troll in disreputable waters (I bought 1K DS8641's from a source in Hong Kong), so I have this: http://ana-3.lcs.mit.edu/~jnc/tech/QSIC/TestCardF.jpg which has a bunch of special circuits on it to test chips to make sure they meet specs; e.g. the large potentiometer is so I can vary the input voltage to see where it switches from 0 to 1, etc. > From: Paul Koning > it would be odd to have one; I can't think of anyone who would expect a > PDP11 to work with part of its devices powered down. For one thing, if > the box with the terminator loses power Forget the terminator - as Jon Elson also points out (his email appeared while I was creating this one), any device which uses interrupts, if un-powered, won't pass grants. > From: allison > Bottom line is someday there will be no DEC parts and what then? I > reserve DEC parts for repairing defunct boards for new and unique build > it would be a waste of scarce material. For actual DEC interface IC's like DC003's, sure. Those are hyper-rare. But DS8641's are available in the 10's of thousands, there's no earthly way we could use them all on repairs. Yes, when they run out, we'll have a problem - but I plan to cross than bridge _if_ and when we get to it. Noel

9 years

Game master?

by bbrown314＠comcast.net

Does anyone remember a subscription time sharing system called, I think, "game master". It was at least available and marketed in the chicago area... possibly nationwide. I just wonder if there is any info on what kind of system it ran on and any preserved info etc. Thanks. -Bob

9 years

Electroluminescent Display aging - Was : Re: Flat panel display rot - "tunnel vision" in electroluminescent and other displays- bad seals.

by ian.finder＠gmail.com

Update: I've swapped the displays and drivers around, and the "tunnel" effect seems to be a property of the panel and not drive electronics. Perhaps they are all high-hour examples? Anyone here an electroluminescent display expert? > > > On Wednesday, July 20, 2016, Ian Finder <ian.finder at gmail.com> wrote: > >> No, I'm not convinced the EL repro isn't a driver electronics issue. >> >> I'm just a little confused about why the issue congregates at the edges >> of the displays. Any ideas why that might be? >> >> I may try swapping the panels around this evening if I am feeling brave. >> >> On Wednesday, July 20, 2016, Brent Hilpert <hilpert at cs.ubc.ca> wrote: >> >>> On 2016-Jul-20, at 12:52 PM, Ian Finder wrote: >>> >>> > I have a few GRiD compass systems and some are suffering from massively >>> > decreased contrast on the edges of the displays: >>> > >>> > [See the system on the left] >>> > https://www.instagram.com/p/BIGGzUzgat-/?taken-by=tr1nitr0n >>> > >>> > [Or this one:] >>> > http://www.ripstick.com/USCM/images/Grid_Compass_1101_ >>> Laptop_in_Box_002.jpg >>> > >>> > Meanwhile, other EL systems I have- like my HP integral PC- haven't >>> > succumbed to this. >>> > >>> > I have seen similar issues on amLCD displays in my Tadpole, Toshiba and >>> > other machines, so this is something we all may have to confront. >>> > >>> > ------- >>> > >>> > I was wondering if the folks here had theories? >>> > >>> > I'm thinking moisture (or air) might be leaking in from the edges of >>> the >>> > glass panes, perhaps from a compromised seal- sorry for the silly >>> picture >>> > but you can see the composition of the display here: >>> > >>> > https://www.instagram.com/p/6BXaLBtSzd/?taken-by=tr1nitr0n >>> > >>> > Does anyone know how one might prevent this from progressing- storage >>> tips? >>> > >>> > Could it be reversed? >>> > >>> > Better yet, does anyone have ideas on how to rapidly dehydrate the >>> display? >>> > Perhaps there is even a way to re-seal them. >>> > >>> > I think all two-glass-pane displays that don't have a vacuum may >>> eventually >>> > succumb to this. >>> > >>> > Perhaps it is just oxidation and not moisture, but I'd love to hear any >>> > theories. >>> >>> >>> Are you convinced this is a panel problem rather than a driver >>> electronics problem? >>> >>> In one picture it looks like the sort of thing that happens when you >>> have to turn up the brightness (for some types of display), resulting in >>> partial illumination in other areas of the screen. >>> >>> I've never had opportunity to repair or work on EL flat-panel displays, >>> I'm not familiar with the driving techniques and requirements, so this is >>> just a query/guess. (I see it's an X/Y matrix drive scheme, but the >>> voltages & timing & phasing I don't know about.) >>> >>> >> >> -- >> Ian Finder >> (206) 395-MIPS >> ian.finder at gmail.com >> >> > > -- > Ian Finder > (206) 395-MIPS > ian.finder at gmail.com > > -- Ian Finder (206) 395-MIPS ian.finder at gmail.com

9 years

PDP15 panel

by COURYHOUSE＠aol.com

even with shipping across the pond a great deal if your system is missing one! Ed# In a message dated 10/25/2016 3:15:40 P.M. US Mountain Standard Time, linimon at lonesome.com writes: If it were on this side of the pond I'll be all over that. mcl

9 years

Need to archive: GRiD Compass Computer Operating System Software

by shatle＠nfldinet.com

-------- Original Message -------- Subject: Need to archive: GRiD Compass Computer Operating System Software From: Ian Finder <ian.finder at gmail.com> Date: Tue, October 25, 2016 7:08 pm To: "cctalk at classiccmp.org" <cctalk at classiccmp.org> Folks, there appears to be a large GRiD-sized hole where archived copies of the Compass Computer Operating System software should be. ... -- Ian Finder (206) 395-MIPS ian.finder at gmail.com >> There's a fairly active GRiD list at http://groups.yahoo.com/group/rugrid-laptop/ You may wish to cross-post there, or I can if you don't wish to join up. Steve

9 years

Need to archive: GRiD Compass Computer Operating System Software

by ian.finder＠gmail.com

Folks, there appears to be a large GRiD-sized hole where archived copies of the Compass Computer Operating System software should be. For those not aware, GRiD had an OS product that was quite advanced for the time- with bitmapped graphics, multitasking, a beautiful forms-driven, UI, etc. Unfortunately, nothing but the basic OS seems to be preserved anywhere- no add-on software, not even the utilities needed to format the hard drive. This is a travesty- GRiD made something far more important than PC clone machines, at one time. *** I'm looking for leads on any software products mentioned below, or at this URL: http://www.1000bit.it/ad/bro/grid/GRID-1984-PriceList.pdf *** I have been buying manuals for the express purpose of scanning, and have a great deal of coverage, but am short on software. I am not opposed to paying for any of this, nor shipping and returning the original copies to the provider at my own expense. I will certainly put all the images in Bitsavers, if Al is okay with that- otherwise they will be made available through some other means. Any leads on GRiD media is appreciated. Thanks, - Ian GRiDWrite, Management Tools, GRiDVT100, and GRiDbasic have already been preserved. [35], [36] and [37-47] would be incredible to find. REF PRODUCT MODEL VERSION NOTES --- ------------------------- ----- ------- ----- 18 GRiD-OS 110X/112X 29200 3.1.0.A [6] 19 GRiD-OS 113X 29210 3.1.5.D 20 GRiD-OS 110X/112X 29200 3.1.0.A 21 Management Tools 21100 3.1.0 22 GRiDMaster 21231 3.1.7 23 GRiDPaint 21214 3.1.5 24 GRiDWrite 21132 3.1.7 25 GRiDAccess 21212 3.1.7 26 GRiDPlan 3.1.5 27 GRiDPlan II 3.2.1 28 GRiDWrite 21132 3.1.7 29 GRiDVT100/Reformat 21191 3.2 30 GRiDVT100/Reformat 21191 3.1.5 31 GRiD3101/Reformat 21151 [7] 32 GRiD3101/Reformat 21151 3.1.5 [7] 33 GRiDTek4016 21228 36.9.4 [7] 34 GRiDTerm/Reformat 21141 3.1.5 35 GRiDTransfer/Partition 21210 36 GRiDRecord/Playback 3.1.5 37 C-86 23032 3.2.0 38 Pascal-86 23025 0.3.1 [1 COPY SOLD] 39 FORTRAN-86 23015 0.3.0 40 PL/M-86 23030 0.2.7 41 BASIC 3.1.0 [7], [1 COPY SOLD] 42 ASM-86 23031 43 GRiDDebug/Devel. Tools 29300 3.1.7 44 GRiDDebug/Devel. Tools 29300 3.0.0 45 GRiDTask II / Windows 21230 3.2 46 GRiDTask II 21230 3.1.7 47 GRiDTask 21230 3.1.7 48 ROM Builder 2.1.0 [7] 49 ROM: GRiD-OS System 112X 24100 3.1.0 [8] 50 ROM: GRiD-OS System 113X 24180 3.1.5 [8] 51 ROM: GRiD-OS Utilities 21400 3.1.0 [8] 52 ROM: GRiDMaster 3.1.7 [8] 53 ROM: GRiDVT100/Reformat 24150 3.2 [8] 54 ROM: GRiDWrite/Term/Refmt 24140 3.1.5 [8] -- Ian Finder (206) 395-MIPS ian.finder at gmail.com

9 years

PDP15 panel

by gtoal＠gtoal.com

Friend of mine pointed this out to me, but I'm a software guy, don't have any use for hardware. Maybe you guys would be interested. http://www.ebay.co.uk/itm/DEC-PDP-15-console-panel-von-1970-/112179257620?h… 8 days left. I think he failed to sell it previously at 130 Euros so that probably sets an upper limit on the auction price. Graham

9 years

Blue top DEC cabinet -- cheap

by jason＠smbfc.net

Hey All, Surplus at work has this right now: http://archives.smbfc.net/uploads/retrocomputing/deccab/ I'm happy to go pay for it and hold it if someone is interested and able to pick it up quickly. --Jason

9 years

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test-drb October 2016