test-drb May 2005

test-drb@ccmp.vtda.org

248 participants
723 discussions

by swtpc6800＠comcast.net

I have made several ROM replacement sockets for the masked programmed Motorola 6800 MIKBUG ROM used in the SWTPC 6800 system. The MCM6830 ROM does not have a EPROM equivalent. The replacement board has a 74LS20 (to map the 4 enables) and a 2716 EPROM. The challenge was to find pins that could be soldered into the ROM board that would plug into the existing socket on the CPU board. I bought several types of pins and headers from surplus stores and Digi-Key. I have determined that capacitor leads are the best solution. Many capacitor lead are made of steel and are much stiffer than resistor leads. The ones I get >from 0.1 uf bypass caps are just the right size for machine tooled sockets. I can make a lower profile adapter then if I use header pins. I describe the process (with pictures) in the Users Guide on this page. http://www.swtpc.com/mholley/ROM_Emulator/ROM_Index.htm Michael Holley

19 years, 6 months

Looking for Comart CRAM-64 switch settings...

by james＠attfield.co.uk

... or manual for same (or CRAM-48) to get my Cromemco Z2 back on line. All information gratefully appreciated. Jim Attfield

19 years, 6 months

31 volumes VMS documentation "Gray wall" available for shipping in Kansas City

by cmcfadden5＠comcast.net

31 volumes VMS 5.0 and release 5.2 documentation in Gray DEC loosleaf binders also System managers guide and Guide to VAX C You pay shipping I'll provide the boxes. Currently in 3 boxes. I can ship without the binders if you want smaller boxes. Pretty heavy. Mike c m c f a d d e n 5 a t c o m c a s t d o t n e t

19 years, 6 months

VCM Stuff for Sale

by marvin＠rain.org

I've posted (and will continue to post) a number of things I don't need on VCM rather than EBay. Some other people have also posted some interesting items. Some of the latest include plastic ready light covers numbered 0 - 7 and 1 - 5 for (I think) the DEC RLO2 disk drive. http://www.vintagecomputermarketplace.com/

19 years, 6 months

Microdata Reality

by aek＠bitsavers.org

> Was it here where I was mentioning it? It was to me Jay and Jim will be interested, I'm sure.

19 years, 6 months

Microdata Reality

by vcf＠siconic.com

I found the manual for the Microdata machine I acquired a couple months ago. Was it here where I was mentioning it? I forget. At any rate, it's a Microdata Reality. -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

19 years, 6 months

Fluke 9010A revisions/upgrades

by leeedavison＠yahoo.co.uk

> Two good links: > <URL: http://tech.quarterarcade.com/tech/Fluke/9010A/ > > and <URL: http://www.gamearchive.com/General/Test_Equipment/ > That last one was very usefull. Now if only there were binary images of the programmable parts somewhere. 8^)= Lee. . ___________________________________________________________ How much free photo storage do you get? Store your holiday snaps for FREE with Yahoo! Photos http://uk.photos.yahoo.com

19 years, 6 months

another ebay weirdness

by James＠jdfogg.com

> Hi folks, > > one simple question: > > What is that card for? > > Please don't laugh - I am a bit too young to know everything > about strange vintage computing stuff.... It passes the bus grant signal along to the next card on the bus. Empty slots between cards need one.

19 years, 6 months

Fluke 9010A revisions/upgrades

by aek＠bitsavers.org

Does anyone have a list of differences between the various versions, and what it takes to upgrade a unit? -- you may want to ask on rec.games.video.arcade.collecting there were a bunch of people using/collecting 9010 stuff there.

19 years, 6 months

IBM PC original power supply problem (long)

by swtpc6800＠comcast.net

Here is a story about the original IBM PC (5150) power supply. There was a defect that showed up a few days before it was to go on sale. The design team flew around the country adding fish paper insulation to the 1700 machines that had shipped to stores. This is from Blue Magic by James Chposky and Ted Leonsis.(1988) ISBN 0-8160-13910-8 The book has a few technical errors, they mix-up 8080 and 8086 chips number in one chapter. The refer to the modem guy as Dennis Glayes (Hayes). In this chapter they refer to a 65 volt power supply (should be watt). The flow of the book tells how the project was kicked off in August 1980 and you could buy one in the store in August 1981. Michael Holley Chapter 18 - The Emergency Brigade Initial shipments of the new PC were made to Computerland outlets and Sears Business Centers less than a week before the machine was scheduled to be unveiled in New York City on Wednesday, August 12, 1981. The shipments were delayed till the last possible minute to avoid leaks to the press. Preferably, the packing boxes with the PCs inside would not even be opened until the afternoon on the day of the official announcement. Then, on August 10, a potentially devastating discovery threatened to cancel the scheduled introduction that so many people had worked so hard and so long to maintain. At about 2:30 in the afternoon, Joe Sarubbi and his staff were running final potentiometer tests to determine if there were any high-voltage leakage on some of the new PCs. Time and again, two of the machines tested positive, which meant that there was a possible dangerous voltage leak. The engineers quickly found that the 65-volt power supplies on the two machines had too close a tolerance between an electrical raw circuit board and the frame of the power supply. This in turn caused too close a spacing that could possibly lead to a short-circuit between the electrical current and the metal frame. The problem was brought to Wilkie's immediate attention. Then a quick call went out to convene the inner circle, along with Howie Davidson, the site general manager at Boca Raton. Sarubbi explained that the power supplies shipped to date had been tested and were shown to be safe. But the fan in the power supply could accumulate enough dust to create a `bridge' to the metal edge of the machine and cause a short-circuit. In addition, a look at worst-case tolerances between the printed circuit card and the frame revealed a tolerance that was unacceptably close, and a relay out of the circuit board had to be added to achieve a permanent fix for the problem. There was only a random chance that this could happen again, but that was still more of a chance than Wilkie and Sarubbi wanted to take. One power supply failure was one failure too many. Meanwhile, more than 1,700 machines-all with short-circuit potentials-were sitting innocently in storage at Computerlands and Sears Business Centers around the country. The IBM PC was intended to be the product to put the Sears Business Centers on the map. Accordingly, IBM had made elaborate arrangements for a full-scale demonstration of the machine to the retailer's senior management committee at the Sears Tower in Chicago on the morning of Tuesday, August 11. Now, here in Boca Raton, less than 18 hours before the big demonstration was set to begin 1,500 miles away, there was concern that the machines at Sears Tower would not only amaze, but could quite actually shock anyone who so much as laid a finger on their casings. Four pairs of eyes turned on Sarubbi. Estridge was the first to speak. "Okay, Joe, what do we do?" Sarubbi said, "We'll have to put a piece of insulation in every machine between the printed circuit board and the power supply cover. Fish paper, which is a non-conductive cardboard bridge, should be sufficient, but this is something we really have to do ourselves." Dan Wilkie suggested the formation of a quick task force. "We can call them 'The Power Supply Brigade,' and fly them out to Sears in Chicago and elsewhere to put in the insulation. But we have to do it now-today. Commercial flights won't get us there in time. We'll have to charter a private jet. When they're finished at Sears, they can go back to the Chicago airport and fly on to the next destination. Frankly, I don't see any other goddam way we can get this done if we still plan to show the machine to Sears tomorrow." Estridge winced. He turned back to Sarubbi and said, "Joe, the decision to go or not to go is yours." What Estridge really meant was, Should we stop the announcement or send out the Brigade? Sarubbi reasoned that not to send the Brigade would mean the PC announcement might be delayed for at least another 30 days. "That would put egg on our face in the industry and throughout the company," he later recalled. "But there was also no way that we could overlook the safety of the unit." Never before in his 30-odd years with the company had Joe Sarubbi been so overwhelmingly grateful that he worked for IBM with its vast resources and capital. He looked back at the frantic, frustrating and yet thoroughly exhilarating year gone by and remembered all the times he gazed across the ocean and said to himself, "Why in the hell did I ever get into this?" Then he pictured the other people on the project and concluded, "They're just like me. We're all of a kind. We're wild ducks within IBM and we're doing what wild ducks do and that's why I have to stay. " Then his thoughts returned to the present. "Uh, Joe," Estridge said. And Sarubbi instinctively knew what a wild duck would do at a time like this, and so he said, "Send the Brigade. And keep the introduction just as it is." "Well, son-of-a-bitch! All right, let's go!" Wilkie shouted as he turned with a big grin and smacked his right fist into his ample left palm. Estridge had to shut his eyes for a moment to pretend he hadn't heard Wilkie, then came the famous grin. Sydnes and Davidson were also smiling, and for that moment, Joe Sarubbi, the old pro, the veteran IBMer, the self-professed beach bum-he was the king of the hill, at the top of the heap. -2- It so happened that Wilkie had a cadre of some 30 devoted admirers on his manufacturing staff. They were a gung-ho crowd who liked to hang around with Dan because he had a tough side with a tender edge and he was eminently fair. And they were loyal to Wilkie, because most of them had never worked for anyone else anywhere else at IBM. Infants all, they thought life at IBM was just like Project Chess, which, of course, made this a very good company to work for. As Wilkie would later reflect, "The team's strength lay in the fact that most of them had never really worked under the strictures of conventional IBM standards." Wilkie walked out of the meeting and gathered his staffers. Eagerly, expectantly, they circled around their leader as he explained what had happened and what had to be done. He said, "I want you guys to go home and get your toothbrushes and a change of clothes and then come right back here and standby to leave for Chicago tonight. You'll be going by private jet out of Boca Raton airport at midnight. We don't know how long you'll be gone, so he packed for at least three days." They all but tore the doors off to get home, grab their gear and get back to the office to be among the first in line to stand by for that emergency flight to Chicago. As soon as the last car squealed out of the IBM parking lot, Sarubbi's office became a war room. From this jerry-built command post, the senior staff on the PC group arranged for a private jet to be ready to leave at midnight for Chicago. The plane landed at 3:00 AM on Tuesday in Chicago. Black limousines were already waiting to whisk the Brigade through the dark streets and to the main entrance of the world's tallest building. Earlier, back at the war room, Sparky Sparks completed special arrangements to admit the Brigade to the Sears Tower at that late hour. The Brigade deployed to the demonstration room like commandos. Within three hours, their assignment was finished; the fish paper was secured in each PC and the machines were tested again for high-voltage leaks. The demonstration for the Sears management could go on as planned and no one had to know what happened in the Sears Tower the night before. Back at Boca Raton a phone call came at about 7:00 AM from somewhere in Chicago: "Mission accomplished!" the Brigade leader said. Sarubbi gave Wilkie the thumbs-up sign. Wilkie went back to his own office and took his spare shaving kit out of a desk drawer. Still not fully awake, he stumbled into the men's room and tried to remember the last time he'd had breakfast at home, followed by an uneventful working day. -3- During the next day and a half, the Power Supply Brigade, with ample supplies of fish paper, flew to Computerland stores in Texas and California. Once again, their missions were accomplished before the debut of the PC. But the power supply episode was still causing upset at Boca Raton. Wilkie recalled, "We were really paranoid about what happened. We said, `My God, what if the world finds out that we had this quality problem?' "In time, the world did find out, but the reaction was the exact opposite of what we thought it would be. People everywhere were saying, `What a class act this company has.' Sears and Computerland told us, `Now we know the kind of treatment we can demand from all the other companies we do business with.' And so," Wilkie said, "instead of this having a negative impact, it became a real plus for the project and an unforgettable experience for those men who flew around the country and worked around the clock to guarantee that the introduction of the PC would stay on schedule." -4- The IBM PC introduced in New York that week had one disk drive, 16 kilobytes of random access memory (RAM) and a $1,595 price tag. (Within four years, other manufacturers would have a "clone" of the basic PC with two disk drives, 256 kilobytes of RAM and it would be available for about $1,000.) By now, despite the company's security precautions and its refusal to give any details of the "new product introduction," enough information had leaked out of IBM to make the purpose of the August 12 announcement well known throughout the industry and on Wall Street. These reports were especially significant to Martin A. Alpert in Cleveland, Ohio. Alpert, a doctor and engineer, was president of a small company called Tecmar, a sort of anagram for "Marty's technology. Tecmar got its start with a computer-based machine used to diagnose lung problems. But the company had the technology in place to build add-on products for the basic IBM PC. Predicting that there would be an enormous market for such add-ons, Alpert put his staff to work designing products for a machine they had never seen. Then he made careful plans to buy an IBM PC when it became available. As it turned out, Tecmar bought the first IBM PC to be sold anywhere.

19 years, 6 months

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test-drb May 2005