test-drb July 2005

test-drb@ccmp.vtda.org

257 participants
628 discussions

Replace roller rubber on HP 9825 tape drive

by dwight.elvey＠amd.com

>From: "Joe R." <rigdonj at cfl.rr.com> > >At 11:59 AM 7/7/05 -0700, Dwight wrote: >>>From: "Joe R." <rigdonj at cfl.rr.com> >>> >>>At 12:10 AM 7/7/05 +0100, you wrote: >>>>> >>>>> Well, I finally got around to attempting to re-spool this stupidly >>>>> designed tape. >>>> >>>>It's actually avery ingenious design (it's the same design, basically, as >>>>QIC tape cartridges). Remember you want a constant tape speed past the >>>>head. By driving the outside of the tape spools at a constant speed >>>>(that's what the belt and drive puck do), rather than turning the spools >>>>themselves by their axles, that's exactly what you get. It avoids the >>>>capstan, pinch roller, slipping clutches, etc, used in audio tape and >>>>cassette recorders. >>> >>> The really ingenous part is that the belt attempts to rotate the take up >>>spool about 10% faster then the other spool. That's what tightens up the >>>tape if it ever gets slack. >>> >>> >>>> >>>>> >>>>> Your description sounds like a different tape than what I was dealing >>>>> with. The tape did not come off of either spool but was instead attached >>>>> onto both spools. > > That really wouldn't make any difference as long as the drive stops when >it sees the BOT/EOT hole and doesn't run the tape off the spool. > >>>> >>>>THere were several designs, sure... >>>> >>>>> >>>>> At any rate, the stupid tensioning belt (whatever its called) broke on >me. >>>>> Oh well, fuck that tape. I'll try to read it anyway (is the tensioning >>>>> belt necessary?) I also noticed numerous spots on the the tape where the >>>> >>>>Of course the belt is necessary. It's how the tape is driven. You can >>>>borrow one from another tape cartridge. >>> >>> Good luck! I could never replace a belt and make it work :=/ >> >>Hi Joe >> I have but I'll admit it was not easy. It is real easy to get >>the tape mangled. I've also repaired the roller at the corners >>on one. >> I don't know how it is done at the factory but they must have >>a special jig to get it all done right. > > Oh, I've gotten them back together (but you need about six hands to do >it)! But even though they're back together exactly like an original they >would never tighten up the slack. They'd run (till the slack got caught and >wrapped under the tape on the take-up spool) but simply never take the >slack out of the tape. Perhaps if I could run them at a slow speed the >slack would eventually work it self out without getting caught and they'd >be ok. But to tell the truth I've never had much luck with tape drives and >I dispise the things! > > Joe Hi Joe I had a trick to get the slack out but it was a long time ago and I've forgotten. I think I just ran is slowly by hand and it took the slack up but I just don't recall. Getting all the pins lined up at the same time was more of an issue. Like you said, it takes six or so hands. I was wondering if one completely unwound it onto a single spool that one could get it to take up the slack by threading it through on its own? It seems like they must have done something like this when they assembled them the first time. The design is such that it always pulls slightly more on the takeup reel. It isn't much but enough to take up the slack if it is only a little. Dwight

18 years, 11 months

Programming Language Inventor or Serial Killer?

by vcf＠siconic.com

http://www.malevole.com/mv/misc/killerquiz/ -- 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 ]

18 years, 11 months

FAQ?

by julesrichardsonuk＠yahoo.co.uk

Where's the online FAQ that contains useful contributions by individuals? I've gone and lost the address and it doesn't seem to be reachable via www.classiccmp.org :-( ta J.

18 years, 11 months

Commodore 64, Commodore 64sx enthusiasts?

by computer＠officereach.net

I'm in possession of a mighty fine collection of commodore equipment that I will be finishing the restoration stuff on (you know, replacing some broken keys, etc.) and one mighty fine Commodore64sx "Portable"; is there anyone on here who has a particular fondness for commodore equipment?

18 years, 11 months

PDP-11/23+ and rx-02 drives, need help!!!

by g-wright＠att.net

Hi, I'm trying to get one of my 11-23's going and finally got around to setting up a TU58 emulator. got it to boot RT-11 and now trying to get a RX-02 working. I have 3 controllers and 3 sets of RX-02's. All do the same thing. The just seems to not be able to find track 1 or Home or ??? The heads just keep going from home to maybe the first tack and back. The heads do load and the system tries quit a few times then pauses and tries again. It then errors on drive failure or read error directory not found, size function failed depends what I ask it to do. I have tried all of the boards and drives. all or them seem to do the same thing. I do not know how good the drives are but can't believe there all bad. I have recheck the switches in the RX-02 and the Jumpers on the cards. Cleaned the drives. tried different disks. Is there some kind of compatibility issue that i do not know about. Or do I have 6 dead drives. The system is a Micro PDP 11, 8 slot Rack mount, with 1 M8189 1123+ 1 M8067 KB 256k Memory 1 M8639 YA MFM rx50 controller 1 M8029 RX-02 controller in this order. Everything else seems to work. I added the floppy card but the rest original. Thanks, Jerry Jerry Wright JLC inc.

18 years, 11 months

WOW!!!! $15k DEC PDP-8 CLASSIC MINICOMPUTER SYSTEM DIGITAL PDP8

by bqt＠Update.UU.SE

On Wed, 6 Jul 2005 William Donzelli <aw288 at osfn.org> wrote: > To: "General Discussion: On-Topic and Off-Topic Posts" > <cctalk at classiccmp.org> > Message-ID: <Pine.SUN.4.20.0507062219110.19631-100000 at osfn.org> > Content-Type: TEXT/PLAIN; charset=US-ASCII > > > Even where IBM cards of that era used 'commodity' components, they were > > usually completely house-marked and impossible for a mere mortal to > > figure out. This goes all the way down to resistor networks and > > resistors/capacitors (except those few that have color-code bands.) > > Unless you get the cross reference... > > For the pre-1978 (or so) machines, you can pretty much debug down to the > chip level. With the right Blue Binders, pretty much every last part is > detailed to a silly extent. WAY more detailed than DEC docs. I don't see how anything could be more documented than having the complete engineering drawings of the whole machine. And that's what you normally got on old DEC machines. That's what I have of the PDP-11/70. Full drawings of every curcuit in the machine. And then I have all the technical manuals for all subsystems that document things in a more text-like manner as well. But as usual: when in doubt, the drawings are the definitive authority. Johnny Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at update.uu.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

18 years, 11 months

Replace roller rubber on HP 9825 tape drive

by dwight.elvey＠amd.com

>From: "Joe R." <rigdonj at cfl.rr.com> > >At 12:10 AM 7/7/05 +0100, you wrote: >>> >>> Well, I finally got around to attempting to re-spool this stupidly >>> designed tape. >> >>It's actually avery ingenious design (it's the same design, basically, as >>QIC tape cartridges). Remember you want a constant tape speed past the >>head. By driving the outside of the tape spools at a constant speed >>(that's what the belt and drive puck do), rather than turning the spools >>themselves by their axles, that's exactly what you get. It avoids the >>capstan, pinch roller, slipping clutches, etc, used in audio tape and >>cassette recorders. > > The really ingenous part is that the belt attempts to rotate the take up >spool about 10% faster then the other spool. That's what tightens up the >tape if it ever gets slack. > > >> >>> >>> Your description sounds like a different tape than what I was dealing >>> with. The tape did not come off of either spool but was instead attached >>> onto both spools. >> >>THere were several designs, sure... >> >>> >>> At any rate, the stupid tensioning belt (whatever its called) broke on me. >>> Oh well, fuck that tape. I'll try to read it anyway (is the tensioning >>> belt necessary?) I also noticed numerous spots on the the tape where the >> >>Of course the belt is necessary. It's how the tape is driven. You can >>borrow one from another tape cartridge. > > Good luck! I could never replace a belt and make it work :=/ Hi Joe I have but I'll admit it was not easy. It is real easy to get the tape mangled. I've also repaired the roller at the corners on one. I don't know how it is done at the factory but they must have a special jig to get it all done right. Dwight ---snip---

18 years, 11 months

source of blank 82S123s?

by dwight.elvey＠amd.com

Hi I doubt that the SuperElf requires high speed as needed by the HP. For the SuperElf, I'd suspect that EPROMs would be fine. Dwight >From: "Joe R." <rigdonj at cfl.rr.com> > >At 08:44 PM 7/6/05 -0700, you wrote: >> Very hard to find in anything less than large (and very expensive) >quantities. >> >> It may not be original equipment, but you could probably cobble up an >adapter to let a UV-EPROM replace the OTP PROM device. > > Er, no. EPROMs won't work. These are the same Bi-Polar PROMs used in the >HP 1000s and I thought of trying to use EPROMS too but EPROMS are too large >and much too slow and have an entirely different pinout. I'm also finding >that the PDP-8s use the same (or VERY similar) BiPolar PROMs. > > Perhaps we should consider a group purchase of a batch of blank BiPolar >PROMS? > > Joe > > > >> >> Happy hunting. >> >>*********** REPLY SEPARATOR *********** >> >>On 06-Jul-05 at 14:58 Ethan Dicks wrote: >> >>>I'm in search of a couple of blank 82S123s for my recently-aquired >>>SuperElf boards. Who still carries such things? >>> >>>Googling on 'blank 82s123' did not turn up anything promising. >>> >>>Thanks, >>> >>>-ethan >> >> >>-=-=-=-=-=-=-=-=-=-=-=- >>Bruce Lane, Owner & Head Hardware Heavy, >>Blue Feather Technologies -- http://www.bluefeathertech.com >>kyrrin (at) bluefeathertech do/t c=o=m >>"If Salvador Dali had owned a computer, would it have been equipped with >surreal ports?" >> >> >> > >

18 years, 11 months

B1000

by aek＠bitsavers.org

Alan Perry Wrote: > I have been looking for a Burroughs B1000 machine for maybe seven years. Have you ever posted this fact to the list? Two years ago, I made a cross-country trip, and one of the stops was to one of the last people who was doing third party service on 19xx's in Louisville. I took all of the maint docs, some of the packs and all of the boards from a 19xx because they were cleaning out a storage unit. I had several more stops to make, and had no room for the complete 1900 that he had. The 1900 CHM has came from a hospital in Kentucky and was picked up by someone who was interested in the machine and drove there and back to pick it up. > I have a bunch of Burroughs B20 workstations Aren't these rebadged Convergent NGENs ? Marvin Johnson has a bunch of docs on these. I didn't realize how sophisticated the OS was on these, probably should see about getting the docs scanned, if he still has the stuff.

18 years, 11 months

E-bay complaints

by marvin＠rain.org

What I don't understand is why most people don't take a look at the Vintage Computer Marketplace on a regular basis. I just sold an MPF-1 on VCM (http://www.vintagecomputermarketplace.com/) for $20.00. Sure, I could have probably gotten more for it on Ebay, but why not list stuff *FIRST* on VCM with a reasonable price that sellers can live with????? And once the ad copy and photo(s) are taken, it is trivial to move the listing over to Ebay if it doesn't sell on VCM. And FWIW Ebay does not always bring the best pricing. An example would be an Altair 8800 that I needed to sell for expenses that sold for $1500 a year or so ago. Considering that I had gone through it and made sure everything worked, and the unit was in excellent condition cosmetically and had the original manual, it probably was worth closer to $2000. Ebay is the lazy way of retail selling without doing research on what something is worth. And taking advantage (in some cases) of people with more money than brains. And I couldn't agree more with Joe's comments; there is a LOT of stuff out there for anyone who takes the time to develop a network and sources. As one example, I would have never gotten the worlds largest supply of existing Polymorphic software, documentations, equipment, etc. without the network I have in place. Nor would I (in years past) have aquired some 50 coinop arcade games at no charge (most are now gone.) > I don't understand why some of ypeople on this list are always > complaining about E-bay. Where else do you think you're going to find a > complete Microprofessor MPF-1 for ?16 and never leave your desk? If you > want bargains you have to go hunt for them or take the occasional one, like > this one, that show up on E-bay. If you don't like E-bay's high prices > then get off the computer and go start looking in the surplus stores, scrap > yards, flea markets, etc etc etc. There are still PLENTY of bargains to be > had. I have a LOT of great computers (3x SB-180s, 2x Rubicons, 2x Altairs, > 10x Intels, 13x AIM-65s, HP-9100, 4x HP-35 Red Dots, 5x HP-1000s, PDP-8, > etc etc etc etc) and NONE of them came from E-bay. I got ALL of them the > hard way, by LOOKING! > > my 2 cents worth, > Joe >

18 years, 11 months

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test-drb July 2005