test-drb May 2010

test-drb@ccmp.vtda.org

189 participants
248 discussions

by mdavidson1963＠gmail.com

I don't know if anyone on the list will care of not, but I just purchased a classic IBM PC (original model 5150) with a monochrome card and monitor for $45 on EBay. According to the seller, it was in storage at a museum for 18 years. They pulled it out, dusted it and it booted DOS right away. It's a dual-floppy model. I won't know more until it arrives, but it was sitting at zero bids until I bid on it with < 15 minutes left in the auction. The description the seller had used was a bit misleading and seemed to imply only the monitor was for sale, but I confirmed it was the entire system. I thought that was a pretty good deal, considering how much I paid for my first IBM PC back in 1983 or so. :) After that, I was at Weird Stuff Warehouse and they were asking $100 just for the monochrome monitor! But, while there, I did pick up some software bargains: A sealed copy of CA-CommonView (C++ GUI Library) for OS/2 for $3 and a copy of SCO Unixware 7 (appears complete) for $5. I love Weird Stuff! Feel free to ignore this if it's too off-topic for the list. :) Mark

14 years

RD53 Restoration

by robert.jarratt＠ntlworld.com

> -----Original Message----- > From: cctalk-bounces at classiccmp.org [mailto:cctalk- > bounces at classiccmp.org] On Behalf Of Rob Jarratt > Sent: 19 May 2010 21:59 > To: 'General Discussion: On-Topic and Off-Topic Posts' > Subject: RE: RD53 Restoration > > > > > -----Original Message----- > > From: cctalk-bounces at classiccmp.org [mailto:cctalk- > > bounces at classiccmp.org] On Behalf Of Tony Duell > > Sent: 19 May 2010 20:25 > > To: cctalk at classiccmp.org > > Subject: Re: RD53 Restoration > > > > > Could that be because the new boards are a different rev and > perhaps > > expect > > > > It's always possible. This is one reason why I really dislike > > board-swapping. It is much easier to repair a configuration that has > > worked once than one you don't know if it should work. > > > > I wonder if this drive depends on reading something from the platter > as > > ssonas the motor is up to speed (say a servo pattern). if so, then if > > the > > heads are moved to far in or out , it may fail > > > > Did this drive suffer from the well-known 'sticky bumper' problem? If > > so, > > what have you done about it? Is it possible that if you just removed > > the > > old bumper that the heads are outside the servo area sometimes? > > > > > Yes, this drive did have a sticky bumper. I resolved it by putting a > very > thin sliver of tape over the sticky bit. I did not loosen any bolts, > but > there is a bit of play in the heads when they are at rest and fully > retracted. > > > Regards > > Rob I have just put the original boards back in and powered up the drive twice. I powered it up twice and both times the heads moved briefly. I used a multimeter (it is all I have) to measure the voltage across the two leads to the coil. The first time I noticed that the voltage briefly went to about 1.3V, the second time it was always 0V although it looked like the multimeter may have noticed a change which was too fast for it. I then tried a few more times and these times the voltage went to 1.3 immediately. Then when the heads moved it went to about 4V and after that it went to 0V. So either I was measuring incorrectly the first two times, or there is still something not right even when the heads do move. Would be interested to know if anyone else sees these voltages. I have another RD53 which I can dig out at the weekend to compare. Thanks Rob

14 years

RD53 Restoration

by ard＠p850ug1.demon.co.uk

> Could that be because the new boards are a different rev and perhaps expect It's always possible. This is one reason why I really dislike board-swapping. It is much easier to repair a configuration that has worked once than one you don't know if it should work. I wonder if this drive depends on reading something from the platter as ssonas the motor is up to speed (say a servo pattern). if so, then if the heads are moved to far in or out , it may fail Did this drive suffer from the well-known 'sticky bumper' problem? If so, what have you done about it? Is it possible that if you just removed the old bumper that the heads are outside the servo area sometimes? > something different? The other thing I have just remembered is that the new > boards are missing the graphite pad under the spindle, but then again I have > run the original boards successfully with the bottom board lifted up so I > can probe voltages, so not sure that would have any effect. That should have no effect at all. -tony

14 years

Edge connector repair

by snhirsch＠gmail.com

There are many outfits offering repair kits for PCB edge connectors, but all of them are $2-300. That's complete overkill for the one or two repairs per year I might need to perform. If I purchase a "frame" of dry-adhesive backed traces from Circuit Medic, what are the chances of using a temperature-controlled bench iron to bond them? Anyone have experience with this? I can see making the $40 investment if it has even a chance of working. Alternately, what other approaches have folks used? Steve --

14 years

$8500 Tandy ad from 1989

by brianlanning＠gmail.com

It's fun to read this stuff. I didn't realize microchannel was available from anyone but IBM. And notice how it's MS(R) OS/2. :-) http://www.stephenbailey.com/technology/what-8499-bought-in-1989/

14 years

[OT] Space Shuttle and ISS (was Re: Amiga 1000 helps win againstpatent troll...)

by shoppa＠trailing-edge.com

> Originally the plan was to replace it with two systems: > * crew launched in an Orion capsule on an Ares I > * cargo (heavy lift) launched on an Ares V > Obama and the NASA administrator want to cancel Ares I, but Congress > might block that. > Ares I is an incredibly stupid design, but if we cancel it we will have > no capability of launching manned missions at all. I've seen this from at least 3 different sides: science, contractor, and government. >From a science perspective, everything being done in the 60's couldn't have been done without the government. Lots of science being done today can't be done without the government. But the scientists don't need any rockets more advanced than what we were doing in the 60's and 70's. They would appreciate simplificiation. But when your instrument is a one of a kind you would kind of prefer that it not blow up on the pad so there is conservatism at least at the expensive end of the project scale. At the low end of the project scale there are plenty of projects who wuold be glad to build five instruments (because they're cheap) with the hope that at least one makes it into space. >From a government perspective, everything has to be done in the "Ten Year Plan" style because there's never enough money to get it done in one year. But stretching it out over ten years in fact makes it more expensive. Things get real expensive for the government, especially a balkanized 40+ year old agency like NASA. Others might say that in a spiteful tone, but I honestly say it in sympathy because I know how people struggle to get good simple cheap science done in an agency that at many levels is thinking only about the ten-year zillion dollar programs. >From the contractor perspective, it's hard to compete against the Russians. You have to do more or better than the Russians, not the same, to compete. But more or better is always more expensive and longer to do... and it's often more than is actually needed too! The big ones try to be clever by buying the cheap startups but I wonder if the cheap startup simply gets stifled in the beauracracy. Tim.

14 years

Looking for CMD CQD-200/TM or CQD-200/M EPROM images

by glen.slick＠gmail.com

Does anyone have a CMD CQD-200/TM or CQD-200/M and an EPROM programmer or other means of reading the EPROM images that could send me a copy? I think I have mostly figured out the CSR decode PAL for a CQD-200/T and programmed a new one and now it responds to both the disk and tape CSRs, but only the tape CSR looks like it has normal values. Maybe I also need to replace the EPROMs with CQD-200/TM or CQD-200/M EPROM images to get it to respond normally to the disk CSR. I have had encouraging results so far doing the same to convert a CQD-220/M into a CQD-220/TM and got it working with both a disk and a tape at the same time. -Glen

14 years

RD53 Restoration

by rescue＠hawkmountain.net

I had one of these drives that behaved this way. As I figured I had nothing to lose, I opened it op and watched it operate.... The theory I came to was that the stopper material changed dimension with age and the drive could not get to track zero. I loosened the stopper and ever so slightly (2-3? thousandths of an inch ?) to let the heads further outward (as I recall). After doing that and reassembling.... it worked fine. I did not put a lot of 'miles' on the disk after that.... I had already put a different disk in service... but for the time I used/recovered data/tested it it powered up 100% every time after that 'repair'. I can't say if my theory is right.... and it could have been just dumb luck... but I thought I'd relay what I did... as if you don't get it to function any other way you don't stand much to lose by trying it. I believe I've read talk on here about homemade 'clean rooms' .... obviously the less dust/particulate matter you get in the drive the better the chances of longer term survival. -- Curt Rob Jarratt wrote: > I have posted before about an RD53 I am trying to get back to working order. > After unsticking the heads I thought I had a working disk as I have been > able to format it and do an image restore of the VMS installation media to > it. However, intermittently it has been failing. When this happens the heads > completely fail to move when I power on the disk, so the controller and > firmware cannot even determine its size. After a few moments the disk spins > down. As I said, this is intermittent, sometimes it will work OK. > > A friend has been helping me and he gave me a complete set of the three > boards in the RD53 from a known working disk (he can't give me the disk for > reasons not worth going into). I changed all three boards and the drive > still completely fails to move the heads, in fact now the fault seems > permanent. My friend suggested that the positioning coil may be faulty. He > measured the resistance of the coil on one of his working disks (at the plug > that goes to the coil from the motor control board), it came to 3 ohms, mine > also measured 3 ohms. I measured the voltage at the plug going to the coil, > one reads 2V the other 3V, but when it works they both go to about 5V. > > Can anyone suggest what might be the problem? > > Thanks > > Rob > >

14 years

[OT] Space Shuttle and ISS (was Re: Amiga 1000 helps)

by Gary＠realtimecomp.com

Scaled Composites was bought by Northrop Grumman in 2007. Doubtful it will compete with it's parent company in any meaningful way. ________________________________ From: cctalk-bounces at classiccmp.org on behalf of Shoppa, Tim Sent: Mon 5/17/2010 10:15 AM To: Gary Subject: Re: [OT] Space Shuttle and ISS (was Re: Amiga 1000 helps) Al writes: > I've always wanted to give Burt Rutan a run at a Space Shuttle > replacement. I bet he'd do something really nice. > His White Knight/Spaceship One combo seems pretty innovative. But, > that's not intended to be a Shuttle replacement. I actually hope he doesn't do "a Space Shuttle replacement". The Space Shuttle is a classic example of scope creep. It had to do everything. In the end it did do most all of everything, and it did it each of them pretty well, but it was much more complicated than needed for any one task, and schedules and budgets were blown out of the water. But excepting schedules and budgets... it did surprisingly well. What Burt Rutan could do, is a family of replacements, each of which does one of the shuttle's tasks well. Some stages/assemblies/technologies would probably end up being shared and that's great. Tim.

14 years

looking for SGI granite mice

by jlobocki＠gmail.com

hello, I'm looking for about 5 (or any number I can get close to) granite SGI mice, the first edition "mouse systems" non-logitech version. I have seen them on ebay, but what they are trying to pull for them seems a bit ridiculous. Thanks! -Joe

14 years

← Newer
1
...
10
11
12
13
14
15
16
...
25
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb May 2010