test-drb February 2015

test-drb@ccmp.vtda.org

203 participants
261 discussions

It's time to restore the 11/45 - progress!

by jacob.ritorto＠gmail.com

Hey everyone, making some progress here -- thanks for all the tips so far! Most of the power regulators are fine, but both H745 regulators seem to be toast. Only getting -1.2 volts; should be -15 and they squeal angrily when I turn the pot. The surplus shops seem to want $200 for one, so that's not an option for me. How does one repair such a beast? thx jake P.S. Also, the main H742s are sagging just a little, but I didn't see an adjustment on them to bring them up. Anyone know where to look?

9 years, 10 months

11/23 clock issue

by jnc＠mercury.lcs.mit.edu

> From: Tothwolf >> Sigh, the crystal output is dead as a doornail. Total flat-line. Guess >> I'm going to have to find a new one... > Does it have to be exactly 13MHz for the system to function correctly? > I have some Fox brand 13.824MHz oscillators Actually, they are exactly 13.824MHz on the 11/23, too. Must be a standard speed... > in my parts cabinets that were leftovers from something back in the mid > 90s (probably modem R&D). Oh, this may be totally fantastic. I spent a chunk of time today looking for a replacement, and so far, no luck. So you may really be a life-saver. A generic search for 13.824MHz crystals turned up a whole bunch of SMD parts, and a few of what I think are actual crystals (two leads), but none of those self-contained DIP oscillator units. I have a couple of 11/23 cards, and although the DIP oscillators on them are >from a number of different manufacturers, they all have the same number on them: "18-12131-00", which must be some standard part number. So I tried looking for that, and all I found were a couple of those part-finder services. So, just for grins, I asked three of them for quotes. Only one replied, and they couldn't find them. So if you've got some of the DIP oscillator units, that'd be a life-saver. I'll contact you off-list to work out the logistics? Thanks! Noel

9 years, 10 months

Radio Shack

by marc.verdiell＠gmail.com

You are so absolutely right, you should have been their marketing director and they'd still be around. People still like to build things just the same! They completely missed the Maker movement, the computer mod stuff, the switch to the web. Also too many stores, too small. The stuff they had in there lately was an appalling mish-mash of uninteresting random stuff. No need to read the news, you could so clearly see that the company management was so totally lost and aimless by just visiting a store. Here in the Valley, Fry's Electronics took over, and then made it so much better. Fry's is where you stop at lunch time, for amateur or professional stuff alike, and get an instant replacement for your fried LM7805. It also keeps our company electronics lab and fab and IT alive. And you can get an espresso at the same time, and a pack of sugar loaded cookies if you are a late night programmer. And a concert on a full size Steinway while you are picking up your capacitor. Let's not forget the best of it, being chased around by the totally incompetent sales person that will convince you that SATA and USB are one and the same thing. Trying to lose him by walking progressively faster. Man, they can walk fast too, these are trained professionals. And for the grand finale, being stripped searched going out the door. How is that for the ultimate nerd store experience! Love it all. The Fry brothers are geniuses. Marc >fahimi wrote: > >RadioShack had it essentially right in the 2014 Super Bowl commercial - the 80s called and they did want their store back. What they screwed up was thinking that meant >the old store had to go and be replaced with the current monstrosity. >RadioShack should have brought back the store of the 1980s and updated it items like cheap cables, Raspberry Pi kits, etc. I.E. hobbyist and do it yourself stuff. Yes, they >still would have to close a number of locations (do you really need a ratshack on every corner?) but what would have been left behind would have thrived...

9 years, 10 months

Xerox 4050/4090 print controllers

by microfilm＠microfilm.kscoxmail.com

I'm doing some cleaning and purging around my shop, and I have a collection of Xerox 4050 and 4090 printers and parts, plus the controllers for these beasts. Is there any interest at all in this equipment? I have to get rid of it, soon, but don't want to simply scrap it if there's someone interested in such niche equipment. The CPU itself is a DJC11, 11/70 on a chip. Other peripherals include a Bus & Tag online interface boardset, graphics processor options (I have one seat of each of the two different options that exist, but the system can only handle one at a time), memory boards, FDDC2 floppy controller (contains an Intel 8086, plus a set of Western Digital chips), a board dedicated to print controller to print engine communications, a hard disk interface (up to four MFM disks, in pairs. Originally had two Fujitsu 56MB disks, later replaced with Seagate drives). The terminal for the system is either a Lear-Siegler ADM-3A, or a Link Technologies terminal in ADM-3A mode, both with minor keyboard modifications. (I have several of these terminals on hand.) Barring interest here, the whole lot will be salvaged and the chips sold off. Keep in mind, this stuff is big. The individual interface boards are slightly larger than a hex-height Unibus board. The card cage for the system is about 24" wide, 18" deep, and 30" tall. The complete controller cabinet, with 9T tape drive, is over 5 feet tall, 3 feet wide, and 2 feet deep. I also have other equipment and supplies (8" and 5.25" floppies, new in sealed packages, for example) to move. Everything is located in Wichita, Kansas. --Shaun Microfilm Services, Inc.

9 years, 10 months

What is this Concurrent Computer Corporation machine?

by pontus＠update.uu.se

Hi My employer has over the years ported our main product to more platforms than I can count. I took inventory of our storage the other day and one machine has left me clueless: The Concurrent Computer Corporation machine: http://www.update.uu.se/~pontus/slask/jobb_vind/DSC_0081.thumb.jpg http://www.update.uu.se/~pontus/slask/jobb_vind/DSC_0082.thumb.jpg http://www.update.uu.se/~pontus/slask/jobb_vind/DSC_0083.thumb.jpg As you see it is one rack with a medium sized computer in it. From the internet and co-workers I've learned that it has either a MIPS or 68k processor and runs a unix version called RTU, for Real Time Unix. CCC was initially Interdata, later Perkin Elmer and then spun off into CCC. Has any cctalk-reader experience with this system? Anything would be interesting to learn. This machine might become available in one way or another later this year. And since I believe it was made in Brittain I've pondered asking TNMOC if they want it. Finally, check the content of the directory above for some more Unix history. Kind Regards, Pontus.

9 years, 10 months

Pdp11/23+ EPROM upgrade

by roeapeterson＠gmail.com

I want to update the EPROMs on my 11/23+, which currently has 2716s. I'm going to need 64k chips, and I understand 2764s won't work on this board. What are my replacement options? I have a fairly capable programmer, it can probably handle anything with 64k capacity. Thanks.

9 years, 10 months

Stupid AC wiring question (220-ish Volts...)

by derschjo＠gmail.com

I picked up a "large" machine* (for certain definitions of large) that's currently configured for 220-240V; my house at the moment lacks 220V receptacles. I was already planning to get an electrician out here to put in some beefier wiring at some point (I have a couple of machines that draw 15-20A off of 120V that I'd like to be able to run) but I wasn't yet planning on doing 220V unless I have to. (It looks like in theory it's possible to reconfigure the supply for 120V but I lack the docs to do so with any level of confidence...) I don't know if this machine works, and I'd rather not invest in 220V wiring quite yet unless it does. And, let's face it, I'm spoiled and I demand instant gratification and I'd like to know as soon as possible if this machine is a basket case or not. So: since all this stuff is in the basement, I'm just about 15 feet away from the dryer, which at first glance runs off an outlet that meets my needs. I even have a NEMA 10-30p plug here that I could wire up to the existing power cable for the computer. But looking into it I have doubts that it's actually that simple; in particular since this house was built well before 1996 and so the outlet is not grounded; there's a neutral lug and two hot lugs (I assume two 120V A/C lines out of phase?) and I'm guessing that might not sit well with the power supply in this computer. But then, I'm a rank amateur when it comes to house wiring and A/C and power supplies and all of that so I thought I'd ask the cctalk collective whether this can be made to work or if I should simply wait for a professional to take care of it... Thanks as always, Josh * An AMT DAP 610, if you must ask. It's an array processor from the late 80s, with 64x64 1-bit processors. If the machine doesn't run I'm pretty much SOL for spare parts, schematics, service manuals, or anything beyond customer-level documentation (which I've recently scanned, btw, if anyone's curious...)

9 years, 10 months

Did Dr. Marc Dean Design the IBM PC or was it Lewis Eggebrecht

by christian_liendo＠yahoo.com

Ok.. So Engadget wrote this article claiming Dr. Mark Dean was chief engineer of the 12-person team that designed the original IBM PC in the early '80s http://www.engadget.com/2015/02/06/mark-dean-pc-pioneer/ I had always thought it was Lewis Eggebrecht. I know there were three teams and one of them won and it was Eggebrecht's team. Did Dr. Marc Dean work on Eggebrecht's team or did he run one of the other ones?

9 years, 10 months

Fry's expansion? was: RE: Radio Shack

by tiggerlasv＠aim.com

On Fri Feb 6 15:09:42 CST 2015, geneb geneb at deltasoft.com wrote: > They're in Renton, WA as well. Now if they'd just keep the parts pegs filled... Yeah, that's been on ongoing issue for Fry's at all of their locations. I've been to Fry's in San Diego, Las Vegas, both Phoenix locations, Wilsonville, and of course the one closest to me in Renton. Great place if you need PC components; they have a lot of odd/unusual items that you might ordinarily only find on-line, or at PC swap-meets. You'll find some killer deals there as well. Several years ago, they were clearing out some 18-gig SCSI Cheetahs. I picked up 4 of them for $20 each. However, as mentioned by Gene, they are frequently out-of-stock on a lot of their electronic components. . . whether it is an obscure item or commonly-used components. I can never rely on finding the right value cap or resistor on their shelf. Another quirk that they have is product placement and pricing. You might find an audio adapter or cable by one manufacturer in the components section at one price, and in the audio section by a different manufacturer, at a significantly different price. I've also noticed that (at least in Renton) that their selection of generic cables has decreased, in favor of expensive brands like Monster or Belkin. Nowadays, I don't even mess with Fry's for A/V or computer cables -- I go straight to MonoPrice.com T

9 years, 10 months

Fry's expansion? was: RE: Radio Shack

by cclist＠sydex.com

On 02/06/2015 11:58 AM, Bill Sudbrink wrote: > Marc Verdiell wrote: >> Here in the Valley, Fry's Electronics took over, and then made it so >> much better. Fry's is where you stop at lunch time, for amateur or >> professional stuff alike, and get an instant replacement for your >> fried LM7805. > > A few years ago, there was a rumor that Fry's was going to expand out > of the Valley. I wonder whether that might happen now that RS is > on its way out. Where have you been the last few years? http://www.frys.com/ac/storeinfo/storelocator --Chuck

9 years, 10 months

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test-drb February 2015