test-drb June 2005

test-drb@ccmp.vtda.org

221 participants
681 discussions

Replace roller rubber on HP 9825 tape drive

by vp＠cs.drexel.edu

"Joe R." <rigdonj at cfl.rr.com> wrote: > >I re-assembled everything and tested it. It had trouble at first: the > >drive would start up but then I'd get error 43 (unexpected BOT or EOT or > >tape error). > > Check your tape! I'll bet that you'll find a spot where the media has > come of the plastic tape and now leaves a clear spot. The EOT sensor sees > the clear spot and thinks that it's the EOT hole. I bet this is what happened. In the following picture you can see the transparent spot that Joe referred to. http://www.series80.org/Articles/DamagedTape-lr.jpg In this case I do not think there is any point reassembling the tape, you are not going to read it with the 9825 tape drive. **vp

19 years, 2 months

Replace roller rubber on HP 9825 tape drive

by vp＠cs.drexel.edu

The 9825 tape drive is very similar (mechanically) to the HP-85 tape drive, so the following link will give you a couple of hints. http://www.series80.org/Articles/capstan-repair.html I mainly use the first method (suggested by Katie) and I have had very good and consistent results. BTW if you click on the pictures you get larger versions. ------------- Be VERY carefull when disassembling the drive, do not remove the screws that hold the top (black) cover to the base of the tape drive, there are a couple of little parts (plastic balls, I think) that will run away. The first time I took an HP-85 apart, I spent a lot of time hunting these damn parts. Anyway, you should be able to remove the capstan and motor assembly without taking the rest of the drive apart. You may need to unsolder the two little tachometer wires (but in some cases they are simply inserted into the PCB). Good luck **vp

19 years, 2 months

PDP11/23+ frustration

by hachti＠hachti.de

Hi folks, today I have powered up my Ampex DFR 996 removable/fixed combined disk drive. After tweaking a bit around the address plug (btw does anybody have an original one?) I got it to start. It said to be ready only once. And made a horrible sound with the head of the removable disk. After that I tried it again but the drive just inserts the head for a short moment (with the same noise) and retracts immediately, shutting down. Are there any opinions, spares, help, TOOLS for my situation? I have no clue if I could be able to find a new pair of heads and install them? Who has experience? What about the head alignment procedure? Now I have no software for my machine. No boot floppy disk. No way to conveniently boot the PDP11. Nothing. What to do next? I could start to program the machine via the monitor, like my Honeywell or a PDP8. But I wanted to run an operation system, use harddisk and floppy etc. The harddisk is VERY heavy (80kg?). Was much work to get it here... Has anybody a replacement? Is anyone interested in taking my whole system? Regards, Philipp

19 years, 2 months

PDP11/23+ frustration

by aek＠bitsavers.org

I disagree on the alignment requirement. It's needed only for pack interchangability. It's 2005, not 1975, and that probably no longer matters. Use a tape, or ftp :-) -- What you actually want to do is align it to work with the OTHER packs that came with the system! I learned this the hard way a LONG time (20+ years) ago when I discovered that none of the packs we had worked any more after I did a head alignment.

19 years, 2 months

Torch Computers Ltd PSU available - anyone need a spare?

by listmailgoeshere＠gmail.com

(I tried to send this to cctech a while ago and don't think it ever made its way onto the list - my apologies for the bandwidth if it actually did...) Hi List, I have here a Farnell N110P411 open-chassis SMPSU. On a relay on one end of the board there is a white sticker with the text "TORCH COMPUTERS LTD (C) 1983" and a QC stamp. If anyone would like this (free, you pay shipping) as a spare part or for a repair/restoration, please speak up by private email. I'm having a clearout and I won't be able to keep this for too much longer before it gets recycled. Ed.

19 years, 2 months

Bernoulli Box (20 MB)

by mbbrutman＠brutman.com

I've got a chance to pick up an older (but not the oldest Bernoulli Box). This is a single drive 20 MB unit that appears to the SCSI. There are no cartridges and it is unknown if it works, but the price is right. (Just shipping.) - Is it worth saving? - How are are cartridges to find? - Assuming the worst, is there a Sam's Computerfacts or other technical documentation for this beast? Thanks, Mike

19 years, 2 months

PDP11/23+ goes on

by ajp166＠bellatlantic.net

> >Subject: Re: PDP11/23+ goes on > From: Philipp Hachtmann <hachti at hachti.de> > Date: Sat, 18 Jun 2005 23:24:38 +0200 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > > >>>I use a ZIP drive and a Qbus MSCP disc controller. > >Sounds interesting. But where to get that MSCP controller?? > >>>A software-only solution (though much slower) is to use the >>>TU58 simulation software that is around > >.... But with it I would be able to boot my machine. At the moment I have >NOTHING to boot up my system, copy disks, transfer data from pc etc... > >But I have a lot (perhaps more than 100) of these 8" disks. > >Can I boot RT11 or RSX11 from floppy??? > >Regards, > >Philipp :-) Yes! You can also boot RT-11 from TU58 (or a simulated one). RT-11 will boot from any block structured device provide there is a driver for it. Allison

19 years, 2 months

Teletypes (was Re: Retrochallenge, 2005)

by aek＠bitsavers.org

> Al Kossow, did I not give you a copy? nope. I did put some tty manuals up on bitsavers that I had.

19 years, 2 months

Spare BYTEs available

by rcini＠optonline.net

All: Before I resort to eBay, I wanted to post a list of my spare BYTE magazines, by year: 1975: 11, 12 1976: 1, 3, 4, 9 1977: 2, 3, 10, 11, 12 1978: 1, 2, 3, 4, 5, 6, 9 1979: 1, 4, 5, 6, 7, 8, 9, 10, 12 1980: 1, 4, 7, 8, 9, 10, 11, 12 1981: 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12 1983: 3, 7, 8, 9, 10, 11, 12 1985: 3, 4, 5, 7, 11, 12 These are available for a trade plus shipping. I'm looking for the following: * BYTEs: 12/76, 1/77, 6/80 (this will give me a complete run from 9/75 to 1/86) * S-100 PROM board that takes EPROMS more dense than 2708s * Altair/IMSAI software * AIM-65 diagnostics ROM * Other??? Please contact me off-list. This grouping of BYTEs will give someone a good head start developing his/her collection. I also have an Excel spreadsheet that has a listing of 700 or so relevant/interesting articles for those maintaining and working with classic computers. Rich Rich Cini Collector of classic computers Build Master for the Altair32 Emulation Project Web site: http://highgate.comm.sfu.ca/~rcini/classiccmp/ /************************************************************/

19 years, 2 months

PDP-8 CPU question

by bqt＠Update.UU.SE

On Sat, 18 Jun 2005 "Joe R." <rigdonj at cfl.rr.com> wrote: > Anyway I've been reading the PDP-8a User's Manual and trying to figure > out what all I have here and I have a question about the PDP-8 CPUs. DEC > offered two different CPUs for the PDP-8, one is the KK8-A which is a > single M8315 card. The other is the KK8-E which consist of an M8300 and > M8310 cards which are the CPU and an M8320 Bus Loads card and a M8330 > Timing Generator card. Can someone explain the differences between the two > and why DEC offered two very different CPUs for the 8? Can I replace > simply the M8300/8310/8320/8330 cards with the M8315? The KK8A cpu takes a single slot, while you need a total of four for the KK8E, which obviously is an advantage, especially in a small 8/a system, where you only have 12 slots. The KK8E have a 1.2uS cycle time, while the KK8A have 1.5uS. Also, the KK8E can be extended with the EAE option, while the KK8A cannot. The KK8A is also microprogrammed. Might be harder to repair (depending on what is broken) but it might also be a bit more reliable. It probably draws a bit less as well. You can replace one with the other. Instruction wise, they are totally compatible. There are some undocumented stuff that they behave differently on, so you can from software tell which CPU you have, but in normal life, it don't make a difference. > I also have a question about the diagnostic paper tapes. Does anyone have > a ROM emulator or other way to load the diagnostics without using a PT > reader? Yes, I know there are some SIMPLE diagnostics that can be loaded > from the Programmer's Panal but I concerned about the more extensive > diagnostics. In fact, I'm wondering if anyone has tried burning the > diagnostics into PROMs and installing them in place of the Boot Roms on the > M8317 card. The boot roms hold very little data, and they simulate the front panel signals for loading into memory. I think you have a total of 64 words, or something like that. > Can anyone explain the purpose of the small card that plugs into the back > of the chassis near the power regulators? It's not mentioned in the User's > Manual and I don't even know it's name. Thom says that it controls the > power and the machine will be completely dead if it fails but that's all > that I know about it. Not sure what you're talking about here. The power regulators for the 8/a have a card-like connector, which you have the mate for on the rear side of the backplane. I suppose you're talking about those. Otherwise I have no idea. The power regulators are neccesary, otherwise nothing works. The core memory for the 8/a also require some voltages on the fifth slot in the backplane, which don't exist on an 8/e. 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

19 years, 2 months

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test-drb June 2005