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101090 discussions

Classic phone repair (was Re: 1966 Mag: Build NE-2....)

by classiccmp＠memory-alpha.org.uk

Hi, > Are you sure it's DTMF? Most GPO 'phones were pulse-dialing, even if they >had a keypad. GPO exchanges didn't eespond ot DTMF signals AFAIK. Yes, it's definitely DTMF....it even has "*" and "#" buttons either side of the "0", unlike any other Trimphones I've seen in the wild. According to the label on the bottom of the broken one, it was supplied by BT rather than the GPO. There's nothing indicating any date of supply or manufacture though. A friend got these phones for me around about 1989/90. He was on an industrial placement at Kidsgrove I think (working for either ICL or STC) and came across an entire skip full of the things next to an office block which was being refurbished. I guess they were used on an internal exchange? BTW Any idea when BT started "DTMF enabling" exchanges (presumably that came in with "System X")? I've got a vague recollection of requesting tone dialling around 1988 give or take a year, and having to have my number changed since only one of the five exchanges covering this area at the time was a System X exchange. > There may have neen an N-diagram for it (there's an archive of >these on the web -- do a google search for 'N-diagram').... Thanks, I'll go take a look. > I didn't think the ringer was that complicatated. Can't you trace >out the schematic? Well, I'm not sure it's just the ringer....when the phone was plugged into the line and someone called the (trim)phone on my extension would completely fail to ring. Also, the exchange would send them a single ring tone, then a few seconds of silence (as if the call had been answered), then another single ring....etc.... I suppose I should sit down and trace out the circuits. Most of the "complicated" stuff seems to be on the keypad (the DTMF encoder), the rest looks fairly straightforward. Just a matter of getting up the enthusiasm, not easy at the moment as I'm still fighting off the effects of coming off anti-depressants.... :-( TTFN - Pete.

18 years, 10 months

tek dos/50 floppy file system format?

by brad＠heeltoe.com

Does anyone have any information on the directory structure of a Tektronix DOS/50 floppy? I'll figure it out by hand, but I thought I'd ask in case someone else has already done it. -brad

18 years, 10 months

Apple Image Writer

by tpeters＠mixcom.com

Hi all, seems I might be getting fired this week. Interviewed for another position at the same place, but I'm up against someone with more experience. So, things to sell. I've got an Apple Image Writer dot-matrix printer to start with. It's the older version, I think based on a C.Itoh design, or maybe the NEC P8023? It's serial interface only, and there's life left in the ribbon. I didn't connect it to a computer but powered up holding the Form Feed button, it prints a barber-pole test. It's model A9M0303, which is not the more widely available ImageWriter II. It's the original. This dude (not me) has pictures of his. Mine looks just like it, except for the serial number: http://www.myoldcomputers.com/museum/perif/print303.htm I can take and send photos of mine in action, if anyone has interest in the printer. I have and will include the original box and packing materials, and the reference manual, but no serial cable (it's standard DB-25.) Is anyone interested in this item? Thanks, Tom ----- 544. [Love] Many a girl has gotten into trouble by obeying that boyological urge. --Katharine Brush (born 1893) --... ...-- -.. . -. ----. --.- --.- -... tpeters at nospam.mixcom.com (remove "nospam") N9QQB (amateur radio) "HEY YOU" (loud shouting) WEB: http://www.mixweb.com/tpeters 43? 7' 17.2" N by 88? 6' 28.9" W, Elevation 815', Grid Square EN53wc WAN/LAN/Telcom Analyst, Tech Writer, MCP, CCNA, Registered Linux User 385531

18 years, 10 months

Classic phone repair (was Re: 1966 Mag: Build NE-2....)

by classiccmp＠memory-alpha.org.uk

Hi, >....no internal schematics for the dialer (keypad/DTMF econder) >or ringer. Actually, I just spotted what you mean about the ringer....I'd forgotten it was a complete circuit board on it's own. It looks pretty simple though, only a handful of components (a transformer, four or six diodes, two BC108Bs and a few resistors/caps). Might have a bash at debugging it tomorrow afternoon. That diagram is still darn useful though, it lets me make sense of the rats nest of wires on the main board. TTFN - Pete.

18 years, 10 months

Classic phone repair (was Re: 1966 Mag: Build NE-2....)

by classiccmp＠memory-alpha.org.uk

Hi, > As expected, while you get an overall schematics of the phone, >there are no internal schematics for the dialer (keypad/DTMF >econder) or ringer. May be some help, though. On the contrary, that looks like exactly what I was looking for (unless the fault is in the keypad unit, LOL). Many thanks. TTFN - Pete.

18 years, 10 months

Three "classic" printers (and a PC) available for free (UK)

by classiccmp＠memory-alpha.org.uk

More stuff to get rid of.... I've got an HP "Laserjet+", a DEC "LA324 MultiPrinter" and an Epson "FX-1170" available for the cost of coming and picking them up from Birmingham. The Epson printer also comes with a free Tandon "Pac 286" AT clone, c/w keyboard and mono monitor (Hercules?) and there might even be a manual or two. It's one of the models with no internal FD and contains two "data pac" receptacles, there's one data pac included (10Mb I think). Never powered any of this stuff up, but it was all working when I received it. Drop me a line off list in interested, thanks. TTFN - Pete.

18 years, 10 months

Advice/Suggestions for repairing Apple III power supply

by derschjo＠msu.edu

Hi all -- Picked up an Apple III this weekend in non-working condition, and I suspect the power supply is at fault. Symptoms are: On power up, a rapid clicking noise is emitted from the power supply (maybe 4Hz or so), and the power LED on the system's motherboard pulses at the same rate. Obviously I haven't run it for more than a few seconds like this :). There are no obviously bad parts (burned parts, swelled/leaking capacitors, etc...) that I can see. I'm mostly a software guy but I'm trying to get more into hardware so that I can better maintain my collection as more stuff starts to break down :). I'd like to make an attempt to fix this but I'm unsure where to start. I have found schematics at: http://www.1000bit.net/SUPPORT/SCHEMA/a3/050-0057-a.jpg. If anyone has any advice, I'd be most appreciative. Thanks in advance! - Josh

18 years, 10 months

Interesting document listing characteristics of pre-1971 spaceborne computer systems

by wbblair3＠yahoo.com

Spaceborne digital computer systems, NASA SPACE VEHICLE DESIGN CRITERIA (Guidance), NASA (Washington, DC, United States), March, 1971, pp. 82, Format(s): PDF 10187k http://trs.nis.nasa.gov/archive/00000106/ ____________________________________________________________________________________ Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase. http://farechase.yahoo.com/

18 years, 10 months

Classiccmpers near Dusseldorf?

by cheri-post＠web.de

Hello Ethan, I am from Bonn, which is an hour away from D?sseldorf. Tell me when you're going to be there. Although I don't have much time at the moment, it maybe it's possible to meet in D?sseldorf. Regards, Pierre > Are there any list members in or around Dusseldorf or Wuppertal? It > looks like the University is sending me there for a few days in > August. I've spent plenty of time in Munich, but don't know much > about other parts of Germany. > > Cheers, > > -ethan > _______________________________________________________________________ Jetzt neu! Sch?tzen Sie Ihren PC mit McAfee und WEB.DE. 3 Monate kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220

18 years, 11 months

AIX 3.2 Installation Media - anyone got a spare set?

by glen.slick＠gmail.com

I rescued some 1990 vintage RS/6000 7012 & 7013 boxes which I don't know much about yet. It appears that AIX v3 is what originally would have been installed on these. Anyone got a spare set of AIX 3.2 installation media that I could use to get an OS loaded on these again, or know where I would have any luck finding this? A quick check of eBay turns up some V5 installation media for sale, but that would most likely choke on these old boxes and I don't see anyone currently listing old AIX versions. -Glen

18 years, 11 months

Classiccmpers near Dusseldorf?

by ethan.dicks＠gmail.com

Are there any list members in or around Dusseldorf or Wuppertal? It looks like the University is sending me there for a few days in August. I've spent plenty of time in Munich, but don't know much about other parts of Germany. Cheers, -ethan

18 years, 11 months

Interesting hardware and computer intellect

by jbmcb1＠gmail.com

The recent discussion on interesting system architectures triggered a memory I have of a documentary on TV somewhere (Discovery? TechTV? PBS?) on evolvable hardware. There was some intrigue in the episode, on investors accusing researchers of bad faith, or lying, or a scam. Hardware was built, I'm pretty sure it was the CAM-Brain, and it was used quite a bit before the company that built it went under (It may have been Genobyte along with ATR, but I remember the company being based out of England) Anyways, this definitely counts as "interesting" hardware. An FPGA based computer that optimizes it's own logic based on a given problem. The CAM-Brain was built, as was an FPGA engine built by HP, and another in Japan somewhere. Here are some links if anyone is interested: The CAM-Brain: http://trappist.elis.ugent.be/~heeckhau/CBM/ Hugo de Garis has an interesting website discussing weather we should build super-brains (Artliects) or not: http://www.iss.whu.edu.cn/degaris/ Adrian Thompson, one of the bigwigs in evolvable hardware design: http://www.cogs.susx.ac.uk/users/adrianth/ade.html

18 years, 11 months

Advice/Suggestions for repairing Apple III power supply

by ethan.dicks＠gmail.com

On 7/23/07, Richard Smith <richard.smith at mewgull.com> wrote: > >Hi all -- > > > >Picked up an Apple III this weekend in non-working condition, and I > >suspect the power supply is at fault. > > > >Symptoms are: On power up, a rapid clicking noise is emitted from > >the power supply (maybe 4Hz or so), and the power LED on the > >system's motherboard pulses at the same rate. > > It's an early switch-mode power supply and the ticking is the device > trying to start up, the control circuit says something is wrong, so > it shuts down. And cycles all over again. I concur. > Disconnect the PSU from the rest of the computer before you try anything else. Indeed, though you might get different behavior with no load whatsoever. This is where those 6V headlamps come in handy. > I would trouble-shoot by looking first at Q1 since that is the > switching transistor, and then maybe all the electrolytics on the +5V > and -5V rails since they are used to provide the reference signal for > the feedback circuit. It's all very simple (compared to modern > switchers). Agreed. One other thing to consider - I've seen this behavior in other machines when there was no problem whatsoever with the PSU - the problem was with the motherboard - a dead short, typically. If you test the PSU with no load or a dummy load, you might get the PSU to start up. If that happens, check the resistance of each voltage input of the motherboard to ground - resistances near 0 or 1 ohm would suggest a problem on that rail. I last saw this behavior when I attempted to use a modern ATX supply on a Blue&White Mac G3 - the PSU ticked and wouldn't start. Turns out that Apple recycled the pin for -5V as an additional ground. Clipping that pin solved the problem (the Mac doesn't need -5V) - it all started normally and runs fine. Stock ATX supply and stock G3 mobo results in ticking. Without further investigation, you can't easily tell, but it could be either the PSU not starting or it could be the protective circuit kicking in. You can do a lot with a VOM and some resistive loads. -ethan

18 years, 11 months

1966 Mag: Build NE-2 Neon Bulb Computer - scan available

by jam＠magic.com

> On Sunday 22 July 2007 19:40, davis wrote: > > I just read an recent article in eetimes that the target life of new > > ICs is 10 years. This is due to metal migration and other (i can't > > remember ) effects that sub-micron processes exhibit. I guess you > > should hang on to all the old gear you can get, because everything > > built today will be land-fill in 10 years. I too have that microwave, > > stainless on the outside for no apparent reason and a painted > > interior. The coating failed after a few years. > > "Target life-time" doesn't mean that every one of the chips will be dead > in 10 years. Realistically, at worst, 1/2 will be dead in 10 years, > and more likely than not it'll be somewhere more favorable on the bell > curve than that [an insignificant amount of dead chips until 10 years > out]. There's plenty of products that were produced 20+ years ago > which had worse "target life" (though not all of it had anything to do > with design). Yes, it's much further out on the normal curve. Chip makers have a strong incentive to make chips have long lifetimes. Nobody is going to buy huge volumes of chips that will all die soon. Complicated chips in modern geometries often take many $1M's and often $10M's to develop when you consider the NRE (a few $M's), the tools, and the number of person-years that go into them. If you build chips that die soon, you won't have any customers and that makes it kind of hard to recoup all of those $M's. You really want the product to become obsolete for some other reason than because the chips start dying. If you were creating a mass-market product, would you want to take a $1B write-off on earnings when the world discovered your stuff dies before it's "natural" obsolescence cycle? The general practice is to take the desired lifetime (often 10 years for the server type of chips that I usually build), worst case average temperature, worst case voltage, maximum frequency, pessimistic estimate of how often each signal inside the chip switches, and worst case process variation. A program then applies a formula to each of the structures in the chip design to see if each meets the lifetime expectation with some probability, well over 99%. The models used by these programs take more and more effects into account with each generation. Foundry's work very hard to have good models and work very hard to understand what structures will age poorly and provide design rules to avoid those. Sometimes they mess up and they spend $100M's or more to fix it because their reputation is valuable. For server type applications, the design teams work very hard to be sure that all of the estimates are *not* optimistic. More often, the estimates are fairly pessimistic. The reason is that the probability needs to be really high if you are putting a lot of chips into a box and want the box itself to have a lifetime of 10 years; if a box has 100 chips with only 99% probability of 10 year lifetime, then the contribution >from the chips alone would mean that only 37% of the boxes last for 10 years. Bringing this somewhat back on topic ... one of the worst factors in the equation is the average operating temperature. The lifetime falls exponentially with the temperature. If you can get your chips 10 degrees cooler, you will greatly extend their life; make sure boxes have good fans and that the fans are working well. I don't know what fudge factors and design life were used for commercial chips from the '70s, but no matter what the target was, keep it cool! James Markevitch

18 years, 11 months

Fwd: [alt.sys.pdp8] Re: Spare cards for 8/L

by legalize＠xmission.com

This message has been forwarded from Usenet. To reply to the original author, use the email address from the forwarded message. Date: Sun, 22 Jul 2007 17:23:01 -0500 Groups: alt.sys.pdp8 From: "Gordon S. Hlavenka" <nospam at crashelex.com> Reply: nospam at crashelex.com Org: Crash Electronics Subject: Re: Spare cards for 8/L Re: <caSdndv8Zf4_zT7bnZ2dnUVZ_hisnZ2d at rcn.net> Id: <aNQoi.3559$Dx2.1358 at newssvr17.news.prodigy.net> ======== Chuck Harris wrote: > Try and order up a 74181 of any flavor, or a 74182. Or a 7438. I used to own an electronics store, and most of the inventory is still stacked around the garage, crawlspace, attic, etc... Anyway, I have about 90 of the 74182, and a dozen 7438. (I don't have any 6100s, sorry :-) I also have a lot of other older ICs; 74xx, 74F, 74S, and so on. Even a few 5400 family. The store is gone; I just couldn't bear to dump all the STUFF, ya know? But if anybody's looking for ICs or discretes to resurrect an old machine, let me know and I might be able to help out for the cost of a SASE and some change. -- Gordon S. Hlavenka http://www.crashelectronics.com It's bad luck to be superstitious

18 years, 11 months

CDC-wren fault

by compoobah＠valleyimplants.com

I have the Seagate version of the CDC Wren-4 (ST4376N) and I was wondering if anyone knew of an easy fix for the following fault: Disk spins up (jumpered to spin up automatically) head lock clicks up, two "burbles" that I think mean head seeks and then the drive shuts off and the heads lock again. I don't see any lights flash on the front, but I'm not sure if it has an activity LED.

18 years, 11 months

1966 Mag: Build NE-2 Neon Bulb Computer

by n8uhn＠yahoo.com

Can Someone repost the link to the scans? it sounds like an interesting project. 1966 Mag: Build NE-2 Neon Bulb Computer > - scan available Bill ____________________________________________________________________________________ Boardwalk for $500? In 2007? Ha! Play Monopoly Here and Now (it's updated for today's economy) at Yahoo! Games. http://get.games.yahoo.com/proddesc?gamekey=monopolyherenow

18 years, 11 months

VMS Empire Source tapes

by dave＠mitton.com

I have two 7" reel mag tapes upon which I recorded the Fortran sources to VMS Empire. I would like to pass them on to someone that can read and play it. Both are dated 3-Oct-80 version V3.B7 One says "DOS Format" on it. I'm not sure if the other is DOS or something else. Each tapes is in a plastic two piece container, and the write rings have been removed. These would have likely been code that I submitted to one of the DECUS releases. Yes, I had something to do with the VMS Empire, but it was mostly debugging and getting it to run on VMS. It was also probably one of the first cases of code pilfering over the DEC network, as my eventual partner in VMS made a copy the code out of my development directory in the Mill. The original code was written by Walter Bright on a DECsystem 10. Depending on the responses, I'll figure out whom to send this to. Given that it was released to DECUS, are the DECUS distributions accessible somewhere? Dave.

18 years, 11 months

AIX 2.1 root passwords (IBM RT)

by julesrichardsonuk＠yahoo.co.uk

Well our IBM RT / 5085 / CATIA setup all checks out and the hard disks seem good - it'll boot to a login prompt on the MDA console (and issue a message about the 5085 interconnect being happy) Unfortunately we have no idea what the root password is :-( Tried the obvious guesses. Are there any kind of tricks in order to reset / break the root password under AIX 2.1? We seem to have a reasonable complement of AIX floppies - perhaps there's a way in there? Or maybe an insecure account which can be used to snarf the passwd file (did AIX use shadow passwords)? Or maybe a way of dropping to single user on the console without a login password? etc. etc. Sadly the hard disks are ESDI - if they were SCSI it'd be trivial to stick them in a different machine and start hacking at the disk block level. Last resort I suppose is to install a copy of the OS on another drive, then attach the current OS drive as a secondary, mount the relevant partition, and edit the 'current' password file. That's a lot of effort though, and I'm not sure what we have in the way of spare ESDI drives anyway. (I don't think we have full install media for additional things like CATIA, so reinstalling the OS over the top of the current data is something we'd like to avoid) cheers Jules

18 years, 11 months

2901 OT

by wbblair3＠yahoo.com

> > William Blair wrote: > > > > Just as an off-topic diversion from a subject that I don't think is actually off-topic, here > > are a number of die photos including some from the AMD 29xx and 29xxx series and others: > > > > http://diephotos.blogspot.com/ > > Brent Hilpert wrote: > > ..no need to consider it off-topic, a lot of the photos in there are of old > chips, including an 8080 and 1802. > > One of the links on that page, > http://www.cacs.louisiana.edu/~mgr/404/burks/pcinfo/hardware/cpu.htm, presents > an interesting overview of microprocs from 70/80/90's, both well-known and > lesser-known ones, far more than just a timeline. Thanks. I guess I should have mentioned that it's my web page. ;-) Best regards, Bill ____________________________________________________________________________________ Yahoo! oneSearch: Finally, mobile search that gives answers, not web links. http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC

18 years, 11 months

Recovering Memorex tapes

by aek＠bitsavers.org

> He mentioned that they were having problems with a particular Memorex > tape. My sympathies. I have hundreds of reels of the crap I have to deal with. > Apparently they've tried > heating it, but this hasn't improved things You have to supply a LOT of air for it to have any effect. The humidity needs to be low, though that is generally a side-effect of getting a chamber up to 55deg C. > can anyone > suggest companies or organisations in Britain which could deal with > this? Not that I have any personal experience with. The brands pointed to by the spectrumdata page are the WORST of the worst (ie. silver label memorex circa. mid-80's) The only person I know who claims to have 'solved' the recovery problem uses custom transports and industrial-sized tape ovens. He is completely unreliable, though, and has personally ripped me off for several thousand dollars worth of tape transports and heads. The two failure modes I've seen on binder is layer-layer adhesion, which can be reduced through baking, and binder deposit if the tape EVER stops moving during reads. The tape should be baked, cooled, then retensioned on a transport with no read-write head, then read using the best transducer you can find WITHOUT STOPPING. There is a high probablity with Memorex tape that even after all that the head will still drop out from binder clog. Analog data recovery and DSP techniques have been used successfully to recover 7 track tapes that were unreadable using the data separators on the drive. Magnetorestrictive transducers like the IBM 3480/3490 heads are more sensitive than conventional inductive heads, but don't map exactly to the track layout of 7 and 9 track drives.

18 years, 11 months

Recovering Memorex tapes

by ljw-cctech＠ljw.me.uk

At the recent BCS at 50 event, I spoke to Dr Jeremy John from the British Library. He is their "Curator of Digital Manuscripts" and as everyone here will know he has his work cut out trying to preserve and access the documents they have. He mentioned that they were having problems with a particular Memorex tape. I think this is 9-track tape. It sounds like the binder has failed, and the oxide is lifting off the tape. Apparently they've tried heating it, but this hasn't improved things (I'm not sure how many tapes they're dealing with). I think the following is what they are dealing with: http://www.spectrumdata.com.au/content.aspx?cid=155 Rather than ask for specific remedial suggestions here, can anyone suggest companies or organisations in Britain which could deal with this? I'll pass suggestions on, or if you think you can help directly then I will put you in touch. Thanks, -- Lawrence Wilkinson lawrence at ljw.me.uk The IBM 360/30 page http://www.ljw.me.uk/ibm360

18 years, 11 months

14.3xxx MHz signal on the ISA bus (was Re: Help identifying a capacitor)

by ethan.dicks＠gmail.com

On 7/20/07, Tony Duell <ard at p850ug1.demon.co.uk> wrote: > The OSC signal was the 14.3xxx MHz master clcok signal in the PC and XT... > > It was used, of course, by the CGA card as the master clock for the video > and colour cubcarrier timing. Some other cards used it, often divided > down, as a master clock. Is there a list anywhere of what cards tended to use that signal? I ask because I manufacture the GG2 Bus+ bus adapter for the Amiga, and, because that signal is on the ISA bus, the designer of the card slapped a $3 oscillator on it to provide it. I have a number of unassembled cards and, honestly, would like to leave that signal off if there's no expectation of folks needing it. These days, the most common use for an ISA bus on an Amiga are either for Ethernet (NE2000 or SMC 80x3) or serial (8250/16550). There are other drivers, but nobody really cares about those anymore. Certainly, nobody I am aware of is hanging a CGA card off of an Amiga, but there's no reason why it wouldn't work from a technical standpoint (and the holes are on the board for the oscillator anyway). So... after the AT faded away and folks were running EGA and VGA on 386s and up, was the 14.3xxx MHz signal still relevant, or just an artifact? -ethan

18 years, 11 months

Telephony switches - is there anyone out there collecting these?

by classiccmp＠memory-alpha.org.uk

Hi, >> Brings back memories....the 2B was my first modem back >>in '85. > > Did you get it from 'Display Electronics'? They were advertising >them at the time.... As a matter of fact I did, though indirectly. One of my friends drove to their shop in London to buy one of those SMD(?) hard drives they were selling at the time and picked up the modem while he was there. I got it about a month later when he got bored of it.... :-) >> I may still have some documentation somewhere if it's any use to you? > > I'd be interested in knowing what you've got, certainly... I do recall getting hold of a technical manual for the unit from a vendor at a rally, since the documentation supplied by Display Electronics was little more than a double sided sheet of A4. I've had a quick look around for it, but it hasn't turned up yet. If I can find it you're more than welcome to have it, but in those days I had a habit of not holding onto documentation when I disposed of stuff.... :-( I'll keep you posted. TTFN - Pete.

18 years, 11 months

EIA connectors

by rcini＠optonline.net

All: I came across a video monitor for one of my machines that has an 8-pin rectangular connector with locking tabs. I remember from my days as an audio-video geek in high school that this is sometimes called an ?EIA connector?. I remember we used these cables to connect JVC and Sony VTR equipment. I?ve done some searching in my usual catalogs and I can?t seem to locate this connector. Does anyone happen to have a manufacturer name/part number for this so I can narrow my search a bit? Thanks. Rich -- Rich Cini Collector of Classic Computers Build Master and lead engineer, Altair32 Emulator http://www.altair32.com http://highgate.comm.sfu.ca/~rcini/classiccmp

18 years, 11 months

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