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Gimix hardware, MFM Hard Drive & 8" Double Side Drives

by Mike Katz

I just purchased an old Gimix computer (now if only I can get it from Orlando to Chicago before my friend goes down there for Christmas). It has an OMTI 20C-1 MFM hard disk controller with a IMI 5018 19MB hard disk drive in it. It has been recommended that i don't even turn the system on with the hard drive in it but rather I remove the drive an I send the IMI 18MB drive directly to a recovery house for data recovery. What do you all think about that? Do any of you have any experience with a recovery service for MFM ST-506 Drives? Also, does anyone have a half height 30MB or larger MFM ST-506 compatible drive that will work with the OMTI 20C controller for sale at a reasonable price. Preferably one that at least spins up. Also, does anyone have the syquest 5MB removable MFM drive and some cartridges, also at a reasonable price. My goal is to equip the Gimix with the following drives: * 2 80 Track DS/DD 5 1/4" half high floppy drives (in the system) * 2 77 Track DS/DD 8" Floppies (I have these in need of cleaning up, just not in a Gimix case) * 1 18 to 50MB MFM half high MFM Hard Drive (system has a full high 18MB drive) * 1 6MB Syquest removable cartridge drive half high (I need to find) At some point I would love to expand the RAM to as close to 1MB as I can (CPU/Motherboard supports up to 1016KB) and add a 3 or 4 port intelligent serial card and an intelligent parallel card (I'm sure these cards are unobtanium). Thank you all for your help If you have a dual 8" drive setup (double sided drives, and enclosure) that you need a good home for, please let me know. I'm in the Chicago Area. Thanks, Mike bitwiz(a)12bitsbest.com

4 months, 1 week

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Looking for my old MicroVAX-II

by Richard Cini

All – This is kind of a crazy request, but many years ago (20+ years), I gave away my MicroVAX-II to someone on the list. I can’t find any of the original emails, but I remember it was in a BA23 tower and included an external table-top drive enclosure with, I think, an RD54 in it. It ran Ultrix, but I can’t remember exactly which version. I’ve floated in-and-out of DEC over the years, and honestly, I’m kind of sorry I gave it away (like so many other systems I had over the years). I had gotten it in a haul from Temple University in the late-1990’s. Anyway, I’d love to get another one. So, if someone is looking to re-home a MicroVAX-II, keep me in mind. Thanks! Rich -- Rich Cini http://cini.classiccmp.org https://github.com/RichCini

4 months, 1 week

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Re: How hard would it be to make new dec tape media?

by Bob Vines

> > ---------- Forwarded message ---------- > From: Paul Koning <paulkoning(a)comcast.net> > To: "cctalk(a)classiccmp.org" <cctalk(a)classiccmp.org> > Cc: > Bcc: > Date: Sun, 2 Nov 2025 14:43:49 -0500 > Subject: [cctalk] Re: How hard would it be to make new dec tape media? > > > > On Nov 2, 2025, at 10:46 AM, Jon Elson via cctalk <cctalk(a)classiccmp.org> > wrote: > > > > On 11/1/25 20:49, ben via cctalk wrote: > >> How hard would it be to make new dec tape media? > >> 60 year tape could use a replacement. > >> Ben. > >> > > DecTape is laminated, ie. it has Mylar on both sides of the oxide. 50 > years ago, we made working replacements from 3/4" instrumentation tape, but > it was NOT laminated. It had a print-through issue where if left sitting > for a few months, it would start getting errors. I have no idea if there > is anywhere you can buy 3/4" instrumentation tape. Maybe you can get 3/4" > video tape. > > Bitsavers has the 3M spec for 480 and 481 sandwich tape, I'm not sure > which of these two is what DEC used. It seems crazy, but it can't hurt to > ask 3M if they still make that stuff. > > paul 10-20 years ago I had a good Point-of-Contact (POC) at 3M (before we both retired). I asked him whether they still (at that time) made DECtape media and was told that 3M had sold their magnetic media operations to another company who also got out of the business before I contacted them. I also asked my POC (and the contact at the other company) if any DECtape media had been kept in a warehouse or similar -- he checked 3M's inventory system and told me that they had no record of any remaining DECtape media. The other company's contact had a similar "you've struck out" story. Bob P.S. I thought that I read here or in a PDP-8-specific forum/mail-list that DECtape wasn't actually laminated on both sides, which apparently explained the visible red oxide material removed from dirty DECtapes while cleaning them (per whoever posted their observations)?

4 months, 1 week

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Re: Looking for an IF-20 interface for an Brother AX-45 typewriter. Saw this today. I was checking for other parts....

by Cliff Stage

I have one IF20 if you are interested.may work still, had allowed printing and disc storage for 2 × novels and and drafts. My only issue is probably the print head on the CE50 typewriter_ printer head needs replacement, but "modem" is ok I bet. Stagecliff(a)gmail.com

4 months, 1 week

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Is Ansgar Kückes on this list, or can someone put me in touch with him?

by bradmcook2013＠gmail.com

Hi all, Sorry to crash your party, but I'm doing research for a book and was hoping to connect with Ansgar Kückes, who owns this site about old school HP computers: https://www.hp9845.net/ Is he on this list? Or does someone know how to reach him? The contact methods on his site don't work anymore. Thanks. Brad

4 months, 1 week

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Unreliable Rotary Potentiometer

by Rob Jarratt

I have the contrast control on the monitor of my Olivetti M24 which has become unreliable, you only need to touch it and the display will disappear completely. It doesn't look too hard to replace the rotary potentiometer, but I was wondering if there is any way to "repair" it to keep the original part. It looks like this: https://1drv.ms/i/c/fc758a5a91b91301/ESPGlbvW5wxGpXPC5kXfzVMBTUUW96GThzDMqZ_ i8jq7tA?e=Ehmo1T Thanks Rob

4 months, 1 week

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reading DECtape

by Guy Fedorkow

We may have a half a dozen DECtapes, probably from the PDP-6 era, perhaps with ITS with content... Is there anyone, preferably in the MIT vicinity, who might have a working DECtape drive and be willing to try to read the tapes? Thanks /guy fedorkow

4 months, 1 week

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Re: reading DECtape

by Guy Fedorkow

Martin, Michael, Thank you! We don't have possession of the tapes yet, but, assuming that happens, I'll try RICM to see if their machines are working again. /guy fedorkow On 11/1/2025 1:00 PM, cctalk-request(a)classiccmp.org wrote: > Date: Fri, 31 Oct 2025 13:22:48 -0700 > From: Martin Eberhard<mfeberhard(a)gmail.com> > Subject: [cctalk] Re: reading DECtape > To:cctalk@classiccmp.org > Message-ID:<57DE7487-B3FA-4200-8D10-ACB4A5353CCE(a)gmail.com> > Content-Type: text/plain; charset=utf-8 > > If you don't find a closer alternative, I have working DECtape drives on my PDP8e (in California), as well as software that allows me to upload an entire tape image as a binary file (via Xmodem protocol). > > I'd be available to do this sometime after November 11. > > Martin > > Typing mangled by iPhone > >> On Oct 31, 2025, at 10:53 AM, Guy Fedorkow via cctalk<cctalk(a)classiccmp.org> wrote: >> >> We may have a half a dozen DECtapes, probably from the PDP-6 era, perhaps with ITS with content... >> Is there anyone, preferably in the MIT vicinity, who might have a working DECtape drive and be willing to try to read the tapes? >> >> Thanks >> /guy fedorkow >> >> >>

4 months, 1 week

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PDP-8 EAE

by Christian Corti

Can someone tell me the frequency of the R405 module in slot PF36 for the EAE of the classic PDP-8? Should it be the same as the R405 processor clock? Christian

4 months, 1 week

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"How to fix a Terak" tape?

by John Foust

I was reading my own Terak web page, and remembering that I'd read Doug Gale's history of computing at Cornell: https://ecommons.cornell.edu/bitstream/handle/1813/36810/00_TheEarlyYearsOf… and it mentions (at page 3.23) a "how to repair a Terak" video they made there, and he claims it was distributed to other universities that were also using Teraks. Has anyone ever seen this tape? - John

4 months, 1 week

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