test-drb December 2007

test-drb@ccmp.vtda.org

215 participants
420 discussions

by healyzh＠aracnet.com

I know there was some interest in 1541-III PCB's recently. Vincent Slyngstad and I have been discussing this since that time, and he has done up schematic in Eagle CAD and has the initial board layout done (actually three different versions using different SD Sockets). The big difference between this and the original design is that it uses through the hole parts wherever possible rather than surface mount parts. I'm trying to find out if anyone here will be interested in boards. I have a design question or two for anyone that is interested. Additionally, I'm looking for anyone familiar with SD Sockets, as neither Vince nor I are, and a couple questions have come up on the socket placement. Information on the 1541-III can be found at the creator, Jan Derogee's website http://jderogee.tripod.com/ Zane -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com (primary) | OpenVMS Enthusiast | | MONK::HEALYZH (DECnet) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | PDP-10 Emulation and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |

16 years, 9 months

GAL16V8 as a modern substitute for a 7447?

by ethan.dicks＠usap.gov

Hi, all, Has anyone here worked with or ever plotted silently to create a moderish 7-segment decoder/driver from a GAL16V8? I'm working on a project made >from classic parts, and am trying to reduce part count rather aggresively, since I'm going to hand-wire it. One thought was to attempt to combine a 7490 _and_ a 7447 in a single GAL16V8. I have blown hundreds of PALs, but have much less experience in designing with them, so I'm not even sure that it's possible to mash together that much logic internally in a 16V8. I know all the outputs are optionally registered, so presuming one has 4 assignable flip-flops, one could theoretically make a counter on the output pins, but what's less clear to me is if you could then take those terms and internally decode them to a 7-segment display. After the large amounts of replies about this 8-way digital switch, I don't necessarily want to clog the list with discissions of what is and isn't possible for a GAL16V8, so if you can remember, please make any suggestions and comments to me directly, not the list. Thanks for any nudges towards a solution. -ethan -- Ethan Dicks, A-333-S Current South Pole Weather at 8-Dec-2007 at 15:40 Z South Pole Station PSC 468 Box 400 Temp -25.4 F (-31.9 C) Windchill -52.5 F (-47.0 C) APO AP 96598 Wind 13.7 kts Grid 12 Barometer 678.8 mb (10674 ft) Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html

16 years, 9 months

How not to fix a classic mac (or: fried logic boards)

by trag＠io.com

>Date: Tue, 13 Nov 2007 11:17:41 -0600 (CST) >From: "Jeff Walther" <trag at io.com> >Subject: Re: How not to fix a classic mac (or: fried logic boards) >To: cctech at classiccmp.org >Message-ID: <12318.209.163.133.242.1194974261.squirrel at webmail.io.com> >Content-Type: text/plain;charset=iso-8859-1 > >> Date: Mon, 12 Nov 2007 22:45:09 -0800 >> From: Josh Dersch <derschjo at msu.edu> >> First point of business, I discharged the CRT. >> To the main chassis. This, as I have now discovered, is not what you >> are supposed to do to discharge the CRT unless you want to destroy the >> logic board. >That particular failure is documented in Larry Pina's "Macintosh Repair >and Upgrade Secrets" and probably in "The Dead Mac Scrolls" as well. I'd >look it up for you, but I don't have my books with me here. Okay, I'm home, I have my books. It says on page 98 that discharging the CRT without a big honking resistor may blow a 74LS38N (U2) on the analog board and the LAG chip on the logic board. The former sounds like it might be fairly standard. The latter sounds like it may be one of the custom programmed PALs or GALs or whatever that Tony was writing about. I wouldn't be surprised if folks had already figured out all the internal logic for the various Mac 128/512/Plus chips though. Finding it might be a bit of a challenge. OTOH, the LAG chip may be fine and it could be U2 on the analog board that has the problem. Jeff Walther

16 years, 10 months

Graphics for S-100 machines (MicroAngelo S-100 Graphics

by marvin＠west.net

Congratulations on the selling price of the MicroAngelo board!!! I did take a look at the bidders and it appears that at least the winning bidder had just registered on Ebay a week ago and had a bidding war with another person who, by their feedback, looks like they had been a member for a while. If that bidding war had not taken place, it would have probably sold in the $30.00 range or so. At least you know how much someone is willing to pay for one of these if you list another one :)! > From: "Robert Stek" <robert.stek at gmail.com> > > No one was more surprised than me at the selling price - and I'm the one who > sold it! I was expecting maybe $20 - $30. I think I even have another one, > but I haven't found it yet. Anyway, it was a nice surprise and will mean > some extra money for Xmas. > > > > Bob Stek > > Saver of Lost Sols

16 years, 10 months

2.11BSD Patch 445; FPSIM fixed; 211bsd runs on systems without FPP

by W.F.J.Mueller＠gsi.de

A note to all 2.11bsd users: Some time ago I looked into running 2.11bsd on systems without floating point unit. The release notes state that this is untested and unsupported, and indeed it didn't work. Robin Birch some time ago fixed part of the issues, see patch 434, but still the kernel paniced when the very first program was started. I managed to localize and fix the problem in sys/pdp/mch_fpsim.s. Steven Schultz right away issued 2.11BSD patch #445. All patches up to and including 445 are provided by Steven under ftp://sg-1.ims.ideas.gd-ais.com/pub/2.11BSD A patch level 445 system will now boot on simh for example on a set cpu 11/70 nofpp 4m configuration and work just fine, albeit a little slower. It should thus also work on a real 11/70 without FPP. I heard of some 11/70 with non-working FPP's, so this maybe good news for the owners. With best regards, Walter Mueller -- Dr. Walter F.J. M?ller Mail: W.F.J.Mueller at gsi.de GSI, Abteilung KP3 Phone: +49-6159-71-2766 D-64291 Darmstadt FAX: +49-6159-71-3762 URL: http://www-linux.gsi.de/~mueller/

16 years, 10 months

free strongarm sa1100 devel system kit

by brad＠heeltoe.com

I have a strongarm (sa1100) development board I'm about to pitch and I thought maybe someone here would want it. It's an "Assabet" board I think. It once booted linux. I have some of the original cdrom's also and the serial cable and power supply. The devel board has ethernet, usb, lcd and sound. It seems like it's 10 years old anyway :-) I believe the part has been EOL'd. If you want it, send me you address and paypal postage. The box weighs 5lbs (.3 stone? :-) -brad Brad Parker Heeltoe Consulting +1-781-483-3101 http://www.heeltoe.com

16 years, 11 months

Mailing list search

by djg＠pdp8.net

I have never gotten it to work. I have tried a couple times over some reasonable long (month?) time and it always says no matches found. Is it just me? http://www.classiccmp.org/pipermail/cctalk/ No matches were found for '(digital or digitally)'

16 years, 11 months

Mail formatting

by tiggerlasv＠aim.com

Something is definitely amiss. . . Take a peek at Henk's last posting, dated Sat Dec 29 05:08:15 CST 2007 The first line is quoted text in response to one of my postings. It looks like the carriage returns were stripped out somehow. Still other postings (where Ethan reported problems) looked fine when I read them.?? There might be TWO different symptoms being displayed. Of course, I noticed that in at least one of my postings, there are some extraneous characters that came across, that weren't in the body of my text. This might be due to the way A-oh-well (AOL) formats their e-mails. Tim ________________________________________________________________________ More new features than ever. Check out the new AIM(R) Mail ! - http://webmail.aim.com

16 years, 11 months

ST506 and/or ST412 hard disk drives

by ard＠p850ug1.demon.co.uk

> I have the same question. The ST506 and ST412 were different > in the WrPrecomp signal being changed to a head select for > the ST412. I think he is looking at documents that state that he > needs a ST506/412 interface. This would be compatable with > just about any MFM drive made after the ST412. > > There was a signal on some drives that came on the data cable. > I think it may have been a write protect but I don't recall > exactly what it was. The ST506 may have used this signal. > I'm not sure if this is what he is talking about. Some, if not most, ST506/ST412 interface drives output a signal on the data cable when that drive is selected. The idea was you could plug the data cables into the controller in any order, and the controller could determine which data connector to use, which receivers to enable, etc. It's a pity few controllers made use of that! I'm not aware of any write-protect signal on the data connector of any such drive. -tony

16 years, 11 months

Modem to Modem without a line simulator?

by tsw-cc＠johana.com

>From a digest article I must comment on... > Is it possible to connect two modems (eg: Hayes 2400 to Hayes 2400) > using a 'dead' or isolated pair of copper wire and have them be able > to communicate? As said before, just get one modem in Originate mode, and the other in Answer mode and go from there. Most "modern" modems (that have some Part 68 certification) can do this quite easily as long as you have access to the command stream on each side. The more difficult is when you don't (usually on one side). Then you attempt to get the "answering" modem in answer mode sending its carrier before he "originating" modem asks for it, and will sense it when it wants to. The part that is touchy is making the timeout on the "answer" side long enough. Ob ClassicComp: I should really try this with my Bell 103A modem (I got one, don't ask!) to see if I can get it to "connect". It might need some DC voltage >from tip to ring (green wire to red wire) to trip some relay (it was before optical couplers!). What an experiment to do! If you want to make two "500" sets talk to each other, a nice 6 Volt battery works quite well placed in series with the two sets. It won't make them ring, but you CAN talk. Use a lantern battery (or 4 D cells) and unless you are making DTMF (touch-tone) on a polarity sensitive set (older 2500 sets) polarity makes little difference. -- Sorry, No signature at the moment. ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs

16 years, 11 months

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test-drb December 2007