test-drb November 2014

test-drb@ccmp.vtda.org

200 participants
279 discussions

by derschjo＠gmail.com

Yet another "oh, let's spend an evening doing a small project" that's ballooned into a major undertaking: I thought I'd try my hand at getting my old PET up and running again; this is an original "chiclet" keyboard model (with 6550 RAMs and no CRT Controller chip). There are a multitude of problems with it (the CPU isn't resetting, I'm sure there's bad RAM and ROM) but I thought I'd start with the most obvious fault -- the video generation. Here's a picture of what it's currently doing (sorry it's not very good...) : http://yahozna.dyndns.org/scratch/pet/oneline.jpg It's only drawing a single line of characters (garbage with some noise due to a very terrible socket holding the character ROM), centered vertically. I initially thought this was a VRAM addressing issue (a stuck counter or whatnot) but it turns out the VSync signal is much too fast -- it's only about 1.2ms long (it's supposed to be about 16ms). I'm actually surprised the monitor can deal with that without damage, so I've been leaving the monitor disconnected while debugging. The HSync period is correct (63.8us or so), and most of the addressing / character display logic (which is driven by earlier portions of the video timing chain) seems to be running correctly, it's just only getting a chance to draw one line of characters before the next frame starts. I'm not having much luck tracing down the fault; I have a schematic (http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/2001/320008…) but it's not making it easy to work out exactly how everything ties together. I can't find anything resembling a service manual for this model, but perhaps I haven't looked hard enough yet. The initial clock (output of E2 pin 6) is correct at 8Mhz; this is divided down to 2Mhz by the counter at C9 (pin 8, the divide by 4 output), which is passed to the 74LS107 at C7 and from here it gets murky and I don't quite see how things fit. I did replace C7 to no effect (ok, I jumped to conclusions...). The divided clock outputs (Q, pins 3/2) from this have a period of about 256us; the LS107 at B6 divides this down to the final period of 1.2ms which is used for the VSync signal. Has anyone here any experience with this hardware? Any tips? Thanks, Josh

11 years

Jack Livesley (co-host with Jim Butterfield) comes to the Personal Computer Museum Saturday

by sbolton＠bfree.on.ca

For those that remember "Bits & Bytes" and "The Academy on Computers" that aired on TVOntario in 1983, I have some great news! While sadly Jim Butterfield passed away in 2007, co-host of the Academy, Jack Livesley, is still around and will be coming to the Personal Computer Museum (http://www.pcmuseum.ca) in Brantford, Ontario, Canada to do a live Q&A Saturday November 15, 2014 at 1:00 PM EST. For those that are not aware, the Personal Computer Museum is a not-for-profit and the only interactive personal computer museum in Canada. It is also home to Canada's largest videogame collection (over 15,000 games and counting) and also home to the largest known collection of CED video discs too! The visit is of significance to me personally because Jack was one of the people that inspired me to choose computers as a career path. He will be accompanied by Karl Hildon, who was the editor of "Transactor" magazine which folks that loved Commodore computers will definitely remember as well. Directions and more information can be found on our website. For a glimpse at Jack and more details on the event, please see http://pcmuseum.ca/jacklivesley.asp Admission is free although donations of electronics and money are always appreciated!

11 years

Sun Intertel NEC for sale

by towtechsteve＠gmail.com

Make Offer If Interested, Thanks Sun Microsystems Server / 2 units - Sunfire 6800 - Removed from working condition Inter-Tel (100+ units / Cords and Headsets were disconnected) - Model ? Standard Digital Terminal - Part Number ? 550.4400 Inter-Tel (50+ units) / Cords and Headsets attached) - Model ? 8520 - Part Number ? 550.7200 NEC (25+ units) / Cords and Headsets attached) - Model ? DTH-8D-2(BK)TEL - Part Number ? Dterm 80 T.O.W.E.R. Surplus Steve Swindell (412) 657-2800 [AIM: (Steve Swindell) towersurplus at gmail.com]

11 years

drop in traffic yesterday

by jwest＠classiccmp.org

The drop in list traffic yesterday was my fault. The problem was on a system unrelated to the classiccmp server, but it only affected the classiccmp server. I believe it would have impacted just over a day of traffic. Problem resolved, and my apologies. Details for the tech oriented: Our hosting service has two front end mail processors (mx1/mx2) that do a lot of quick/basic checks before passing mail onto the backend mailbox servers. One of them had an issue and had to be restored from a backup that was a couple weeks old. We don't normally think anything of that in this particular case, because the config files on a front end mx basically never change so any backup is good. Much to my chagrin, I didn't realize that the backup for mx2 was taken BEFORE switching the mail stream for classiccmp.org >from the old ccmp server to the new one. Since both front end mail servers are equal preference, that means that about half the inbound mail for classiccmp.org was being directed to the old server which has pretty much been sliced up as things were migrated to the new server. Last night I changed mx2 to deliver to the correct/new classiccmp server (mx1 was already doing so), and that fixed the problem. Newbie mistake, my apologies. Best, J

11 years

Fwd: Undelivered Mail Returned to Sender

by woyciesjes＠sbcglobal.net

Hrm? -------- Forwarded Message -------- Subject: Undelivered Mail Returned to Sender Date: Thu, 13 Nov 2014 18:39:13 -0600 (CST) From: Mail Delivery System <MAILER-DAEMON at classiccmp.org> To: woyciesjes at sbcglobal.net This is the mail system at host huey.classiccmp.org. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system <General at classiccmp.org>: unknown user: "general" -- --- Dave Woyciesjes --- CompTIA A+ Certified IT Tech - http://certification.comptia.org/ --- HDI Certified Support Center Analyst - http://www.ThinkHDI.com/ Registered Linux user number 464583 "Computers have lots of memory but no imagination." "The problem with troubleshooting is that trouble shoots back." - from some guy on the internet.

11 years

HP3000 Boards Available

by leec2124＠gmail.com

I have several untested spare boards for HP3000 9xx series systems available for shipping from 94025. 1. 802.3 interface board (HP 27125-80201) - I have a mystery cable that may go with this board, included. 2. HP-IB interface (HP 27110-60301) with couple cables 3. MUX card (HP 27140-60001) - this may be for a HP-UX 800 Series machines. First come, first serve. Contact me off-list via lee_courtney at acm.org -- Lee Courtney

11 years

CPT wordprocessors

by simski＠dds.nl

Hello all, we have two machines in our collection: a 8515 and a phoenix, both rebranded to OCE, a dutch plotter manufacurer. Both machines are missing their bootmedia. is someone able to copy those or image them? The 8515 uses 8" media, the phoenix 3.5" -- Met vriendelijke Groet, Simon Claessen drukknop.nl

11 years

Full-size 600 ohm telo transformers

by cclist＠sydex.com

I've got a bunch (maybe half a dozen) 600 ohm - to -600 ohm telco line transformers. Nice units, maybe 5 inches tall by 2.5 inches wide, and potted. Use 4 8/32 screws for mounting. Is there any use for this stuff? Does anyone want them? --Chuck

11 years

Wanted: Altair / S-100 serial comms board w/ documentation

by drlegendre＠gmail.com

Just taking a stab.. I've run out of options trying to locate docs for the lone S-100 serial board in my stash, so I think it's time to look for a new unit. I don't own a logic analyzer, nor have I sufficient experience to figure out how to put my current board to use in the absence of docs.. so it goes. Does anyone have an S-100 (for Altair, in specific) RS-232 / serial communications board with available documentation? Just looking for something that can be made to work with a common serial terminal (emulated) so I can play around with BASIC and so forth. Plan is to use a basic 486 / Pentium laptop running Linux + Minicom or similar to emulate a VT-whatever on the Altair's comms port. (As an aside.. a bit of a mea culpa - I +did+ once own a genuine ITT (I think it was ITT) tele-tank with a paper tape machine. Picked it up for $15 at a local electronics surplus - AxMan - back in the early 1980s. It didn't work right.. or at least I had no idea what to do with it. When powered-up, it would begin to print blank lines over & over, line after line.. just sat there, running away like crazy doing nothing. I had not the slightest idea how to deal with it, so I removed the works >from the top of the base, and THREW IT OUT OF MY SECOND-FLOOR BEDROOM WINDOW. It was so heavy, I didn't want to have to carry it back down. The base served as an excellent printer stand for several years, and the not-so-obvious access panel did well to conceal various contraband during the same period.)

11 years

Kearney & Trecker Core memory, may be PDP8

by anders＠abc80.net

Hello, Here is some hi resolution pictures on front/back of a MM8-AB 16K core. Fits perfectly in a PDP-8a that has the correct power supply (G8018). http://www.abc80.net/docs/pdp8/pdp8a/DSC_2252.JPG http://www.abc80.net/docs/pdp8/pdp8a/DSC_2253.JPG The picture on ebay is really bad, but you can see that it is the same. /Anders > Message: 5 > Date: Wed, 12 Nov 2014 08:47:37 +0100 > From: Mattis Lind <mattislind at gmail.com> > To: "General Discussion: On-Topic and Off-Topic Posts" > <cctalk at classiccmp.org> > Subject: Re: Kearney & Trecker Core memory, may be PDP8 > Message-ID: > <CABr82SLXMERy5JWVtoCvpC07EuLJydYLvcEuGEaTyU=QHB00Xw at mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > This is another Ebay item which seems to be identical : > http://www.ebay.com/itm/DEC-H219B-16K-x-12-Core-Memory-Stack-Board-Flip-Chi… > . > > Also indicate PDP8/a system core mem, MM8-AB. > > 2014-11-12 8:41 GMT+01:00 Mattis Lind <mattislind at gmail.com>: > >> Looking at page 3-17 of >> http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp8/pdp8a/EK-8A001-OP… >> shows that it is as far as I can see identical to the 16 k MM8-AB. >> >> 2014-11-12 8:13 GMT+01:00 Paul Anderson <useddec at gmail.com>: >> >>> pic #4 shows a DEC core sticker on the back, but out of focus. >>> >>> On Wed, Nov 12, 2014 at 1:09 AM, jwsmobile <jws at jwsss.com> wrote: >>> >>> > >>> > On 11/11/2014 9:12 PM, Jon Elson wrote: >>> > >>> >> On 11/11/2014 09:18 PM, Johnny Billquist wrote: >>> >> >>> >>> On 2014-11-12 04:00, Jon Elson wrote: >>> >>> >>> >>>> On 11/11/2014 07:33 PM, jwsmobile wrote: >>> >>>> >>> >>>>> I can't tell for sure, but this auction may be for PDP8 core >>> board. >>> >>>>> >>> >>>>> KT-KEARNEY-TRECKER-ASSY-KT83-0933-KT84-020-SYSTEM-BOARD >>> >>>>> >>> >>>>> http://www.ebay.com/itm/181565552717 >>> >>>>> >>> >>>>> >>> >>>> >>> >>> The fact that the board have four edge connectors and not six >>> totally >>> >>> excludes PDP-11. >>> >>> >>> >> The first and last picture of the ebay listing above clearly has SIX >>> edge >>> >> connectors. >>> >> And, in fact, a number of PDP-11 peripheral boards had only 4 >>> connectors. >>> >> CPU boards and memory did usually have 6. >>> >> >>> >> Jon >>> >> >>> >> >>> >> I based my PDP8 on googling and looking for comments about the >>> processor >>> > type. There was a history page which said they used PDP8s in their >>> > designs. I know that the 6 up is more common for PDP11, but wanted >>> to >>> > throw it out there. I figured a core board of the right variety for >>> $195 >>> > might be a steal since the seller didn't list it to be on the DEC >>> hardware >>> > searches on Ebay. >>> > >>> > Thanks for Al's comment on the 6800 board. I see about half of all >>> photos >>> > being crap these days on ebay. I was crossing fingers it would be a >>> design >>> > that started out as an actual dec, and maybe had a small board built >>> up >>> > with a Harris pdp processor on it. I know that is a really long >>> shot, >>> but >>> > not impossible. >>> > >>> > thanks for the comments. >>> > Jim >>> > >>> >> >> >

11 years

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test-drb November 2014