test-drb

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101090 discussions

Static RAM chip source (& S-100 related questions...)

by derschjo＠mail.msu.edu

Hi all -- I finally have procured enough hardware to get my IMSAI 8080 running again, albeit in a very barebones state. I currently have only 16K of working (and compatible) memory and am trying to get an additional 32K static RAM board working again (It's an IMS board, see: http://www.s100computers.com/Hardware%20Folder/IMS/32K%20Static%20RAM/32K%2…) Mine is missing a number of memory chips; these are 5257 4Kx1 (I believe >from my research the TMS4044 is equivalent). Can anyone suggest a reputable place to pick up half a dozen or so of these for a reasonable price? There are a few on ebay for $6 each, which seems a little steep (but perhaps my expectations are out of order...) I'm also looking for a manual for a PSS RAM65. I believe this is a 16K DRAM board. It's the only S-100 board in my collection that I haven't managed to find a manual or schematic for... Once I get the memory situation resolved I hope to get a floppy disk system working. I currently have a Tarbell 1011D in unknown condition -- is this a decent card to work with (and can it be made to work with 5.25" drives?), or would I be better off finding something else? Thanks as always, Josh

15 years, 7 months

transistor replacements

by dgari＠msn.com

Assuming they are complementary, these oughta work: http://www.nteinc.com/specs/100to199/pdf/nte188.pdf _

15 years, 7 months

Terminals...

by bqt＠softjar.se

Dave McGuire <mcguire at neurotica.com> wrote: > On 8/13/10 4:27 AM, Johnny Billquist wrote: >>> >> Not at all, I just wanted to know what he didn't like about them. The >>> >> only thing I dislike about VT420s is the non-removable power cables. >> > >> > Huh? My VT420s have removable power cords... > > Mine do not. This is interesting. I know there was a variation of > the VT320 (yes 320) that had a removable power cord, but they're not > terribly common. Apparently there's a removable-cord version of the > VT420 as well. Interesting! Hmm. Unfortunately I don't have any VT320 around anymore, since all of them have broken down (flybacks mostly). But I've had atleast five of them over time, and all have had removable cords. I wonder if this might be more of a european thing. Since different countries in Europe use different power plugs, it makes sense to have the power cord detachable. There is more or less a standard format plug that goes into any kind of computer equipment, but the wall plug differs between countries. So you usually don't use a fixed power cord, but instead the standard equipment power connector on your equipment, and then ship whatever power cord is used in that country. >> > The VT420 have both DB25 and MMJ, so I can't see how that could annoy >> > anyone. (As do all DEC terminals from the VT220 onwards.) > > Now waitaminute. I am staring at the back of both a VT420 and VT320 > right now, on the table opposite my desk. Neither of them have DB25s, > only MMJs. The VT420 has what looks like a knock-out that's about the > right size for a DB25. > > Apparently versions with and without DB25s exist as well! Apparently so. :-) > That same (rare-to-me) VT320 I mentioned above that has a removable > power cord also has a DB25. Out of a few hundred VT320s that have gone > through my hands, it's the only one I've ever seen that has either a > removable power cord or a DB25. I've never seen a VT420 with either of > those, and until now, I haven't even heard of their existence. Well, I have four VT420 at home right now, and they all have both a DB25 and detachable power cord. Since I was feeling creative tonight, I even took pictures of the back side of all terminals I have at home. So here is a link to where you can see the backside of: VT-330, VT-420, VT-510, VT-520 and VT-525. All of them have DB25 and all of them have detachable power cords. http://www.update.uu.se/~bqt/vt (Argh, I just realized I missed the VT-240 I have, but oh well...) William Donzelli <wdonzelli at gmail.com> wrote: >> > Huh? My VT420s have removable power cords... > > Some do, some do not. Yup. I just learned. All I've ever seen have been with detachable cords. But as I wrote above, I bet this is a european thing. >> > The VT420 have both DB25 and MMJ, > > Some do, some do not. Of the fifty or so I had recently, I think only > one had the DB25 in addition to MMJ. All mine do, and I have four right here. >> > However, MMJ is actually very nice. Too bad it didn't catch on outside of >> > DEC. But I try to use it for everything I can at home. > > MMJ "fixed" a problem that really was no big deal - people confusing > RJ45 serial with ethernet. I think the real reason was to lock people > into MMJ by doing the old lets-violate-the-standard trick. In my book, > DEC is guilty as anyone else here. Huh? That is totally backwards in more than one way. Yes, MMJ "fixed" one thing. It has nothing to do with ethernet, but all to do with people (and companies) who couldn't figure out how to wire a DB25. Almost all companies got the gender wrong on their equipment. In addition to that, many couldn't figure out what a DTE and DCE was. Now, that is called standard violation. Causing people to have cables they think they can connect, but which don't work. DEC is one of the two companies that did get it right (the other one being HP). To this day, it totally amaze me how so many companies couldn't get this right. And >from that perspective it don't surprise me when people around here don't get it either (there was a long thread not long ago, which I declined to even participate in). RS-232 is so simple that it's hard to get wrong. There is only two things you can mess up with. Connector gender, and DTE vs DCE. How can people find that so difficult??? And if people and companies had actually stayed with the standard, you wouldn't even had been able to mix those to parameters up. A DTE *should* have a *male* DB25. A DCE *should* have a female DB25. A male-male cable should be crossed, a female-female cable should be crossed, a male-female cable should be straight. There is nothing more to it. All terminals and computers are DTEs. Modems are DCEs. But it you absolutely wanted to, feel free to wire a modem up as a DTE. It will work just fine, just as long as you fit the right DB25 to it, and wire it up accordingly. But no. Companies just loved putting female DB25 on their terminals, and wire them up as DTEs. Or put male DB25 on their computers, and wire them up as DCEs. *Idiots* That is called violating the standards. And to make matters ridiculously worse, we have IBM. Who simply put just raped the RS-232 standard by using a DE9, moving one or two pins in a totally non-logical way, changing the gender, *and* sortof wiring it as a DCE. They should be taken out to the back and shot. IBM have caused more damage to the computer world than all other companies put together. Here is a simple tip for the next time you wire a RS-232 up. Measure pin 2 and 3 on the equipment. One should at around -12V, while the other is around 0. Do this on both sides. Then wire the -12V from one side to the 0V on the other for both 2 and 3. And run pin 7 straight through. And that's it. You now have a correct RS-232 cable, albeit just the data leads. You can wire the rest up if it amuse you. The most important ones are DCD, DTR, DSR, RTS, CTS. For a DTE-DTE, you should wire CTS to RTS and DCD+DSR to DTR. Very simple. And if I remember right, we're talking about pines 4,5,6,8 and 20. But I'd usually check the RS-232 DB25 connector layout before I try to wire a full cable up. Most of the time I'm happy with just 2,3 and 7 anyway, since I don't do hardware flow control (another RS-232 standards violation, by the way, and which DEC did not do). But having the DSR signal is useful to detect if someone gets disconnected. What DEC did with MMJ was in no way violating any standard. Noone in his right mind would think that an MMJ was an RS-232. So what standard did they violate (if I may ask?). Hmm, I seem to remember that the signalling in the MMJ is even called DEC-423, but I might be remembering wrong. It is pretty much compatible with RS-423 anyway (might be equivalent), and you can usually get away with connecting that directly with RS-232, but they are not really the same thing. (Hmm, looking at RS-423, it would appear that DEC-423 is a superset, since DEC-423 don't actually use a common ground for everything, but use one ground for all transmitted signals, and one ground for all received signals). So, the signalling in the MMJ connector is only claimed to be communicating using DEC-423. How would that violate any standard? If DEC had said that it was an RS-232 port, then they would have violated the RS-232 standard. (I guess I'm confused at your definition of violating a standard.) What MMJ solved was that they removed the gender issues, and they simplified the DTE/DCE issues. Your cable is either straight or crossed (either flat or turned 180? looking from one end to the other). They also simplified the assembly of the cables compared to RS-232. The fact that MMJ Ethernet vs. RS-232 on a RJ45? Give me a break. None of that even existed when the MMJ came about. And the idea of putting RS-252 on an RJ45 is something I'd call violating a standard, if anything. But it comes with the one-connector-for-everything that some people are so fond of. So you also have telephony on RJ45, to make life really interesting... And all running through one patch panel. >> > The reliability of the VT420 seems to be pretty decent. I've had many more >> > VT320 fail on me. But we have to remember that we're talking about 20+ year >> > old equipment now... > > Yes, but these were built well towards the end of the monochrome CRT era. I don't know. When was the end of the monochrome CRT era? Has it ended yet? Dave McGuire <mcguire at neurotica.com> wrote: > On 8/13/10 5:51 PM, Johnny Billquist wrote: >>> >> AFAIK the VT420 supports Sixel, but not ReGIS. >> > >> > No. The last graphic terminal was the VT340. >> > The VT420 don't support any graphics, unless you count the user defined >> > font as graphics. >> > >> > Graphics implies either SIXEL, ReGIS or both. Actually, I've never seen >> > any terminal that supports sixel but not ReGIS, however, several >> > printers is of that inclination. >> > >> > (Although I'm sure someone will now recall some terminal that do sixel >> > but not ReGIS just because I wrote the above... :-) ). > > I've never *used* Sixel graphics on a VT420, but the manual clearly > states that it supports the Sixel format. > > (flip flip) > > Ok, I just went back and re-read it. It "supports Sixel format" as a > way to encode user-definable character sets. So you're right I suppose, > it ALMOST supports Sixel graphics! ;) I said "unless you count the used defined font". :-) All that said, I know some crazy person wrote a GIF viewer for the VT320, using the user defined font to pull it off. Dave McGuire <mcguire at neurotica.com> wrote: On 8/13/10 8:49 PM, William Donzelli wrote: >>> >> However, MMJ is actually very nice. Too bad it didn't catch on outside of >>> >> DEC. But I try to use it for everything I can at home. >> > >> > MMJ "fixed" a problem that really was no big deal - people confusing >> > RJ45 serial with ethernet. > > Huh? I don't see how that can be. The 802.3i standard which defined > 10baseT Ethernet on RJ45 connectors came out in 1990, while the first > terminal to implement MMJ was the VT320, which predates that by three years. Ouch. You're right. For some reason I was thinking that the VT220 also had MMJ, but it didn't. That only came with the VT320... But I can't see the relevance of MMJ vs. RJ45 either, for various reasons mentioned above. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

15 years, 7 months

Osborne 1 microcomputer + software available

by biblioamy＠gmail.com

I have an Osborne 1 Microcomputer with software available, as described below, for free or just pay shipping if it needs to be shipped. I was informed I could post a listing on the Classiccmp site by just sending this email. I need to find an interested home for it! Thanks in advance for your help if you can. Osborne 1 computer + software pay shipping only Osborne 1 Computer, 1981, the "first commercially successful portable microcomputer" (Wikipedia). We are the second owners. Last we checked, several years ago, it runs perfectly. Software included: CP/M tm V2.2 System & Utility copyright 1981 by Digital Research Wordstar/Mailmerge Version 2.26 copyright 1981 by MicroPro Int. CBasic/MBasic copyright 1981 by Microsoft Supercalc v1.12 copyright 1982 by Sorcim Corp. Personal Pearl copyright 1982 Relational Systems version 1.02 (all 7 diskettes, Disk 2 Design Reports, Disk 3 Install Forms and Reports, Disk 4 Enter Data, Disk 5 Produce Reports, Disk 6 File Maintenance, Disk 7 Startup Disk) AMCALL copyright MicroCALL Services version 2.06 ~ Amy (Longmont, Colorado)

15 years, 7 months

transistor replacements

by dgriffi＠cs.csubak.edu

I'm playing around with an old gizmo that calls for mps-u05 and mps-u55 transistors. They're obsolete, but easy enough to find on Ebay. I would rather use something more modern, particularly because these are in a power supply. Can someone suggest substitutes in a TO-220 case? I'm not coming up with anything satisfying with Mouser's select-o-matic. -- David Griffith dgriffi at cs.csubak.edu A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

15 years, 7 months

cctech Digest, Vol 84, Issue 16

by jonas＠otter.se

Use alkaline or silver oxide. Any small error in exposure caused by the difference in voltage is compensated for by the exposure latitude of the film. I had my OM-1 modified with the Schottky diode setup, works perfectly. I believe it would probably work just as well without the diode. And as far as the diode goes, I have heard one person claim that it is entirely pointless because the voltage drop over the diode varies so much with the ambient temperature that the compensating effect is essentially nullified. Don't waste your money on any fancy adapters, or expensive zinc-air batteries either. Alkalines work perfectly well enough. /Jonas On 8/13/2010, somebody and Tony Duell wrote: >> battery: that's a problem with my Minolta SRT series SLRs, where the > >I think that's unlikey. The voltage is not too critical (it needs to be >between 3-ish ance 5V, I think). I have had success using a couple of AA >cells in series (normal 1.5V Duracells) as a replaemeent for a backup >coil cell in some systems. No, they don't last as long (shelf life is >lower), but they are avaialble _anywhere_. > >> excellent TTL metering doesn't work anymore because it was designed to >> be powered by mercury cells that I can't buy anymore. > > >While you can, alas, no longer get mercury batteries, there are plenty of >work-arounds for this. If the STT101 I've just picked up from my pile of >odd cameras is anythign to go by, it takes a single PX13/PX625 cell. >There is an alkaline equivelent that's the same size, but highter >voltage, and I susepct, alas, the Mimnolta meter woudl care about that. >Often connecting a single shottky diode in sereis with the cell will do >the teick, if there's space inside the camera (sorry, I've not pulled the >bottm plate to check), then it's easy to add it. If there isn't space, >then there's a fairly expensive adapterwhich takes a smaller alkanline >cell and includes a series diode. Or you could make soemthing like that. >Or a new battrey cover containing contacts with wires leading to an >external PSU of the right voltage. >

15 years, 7 months

Pronouncing acronyms (was Re: DEC acronyms)

by jonas＠otter.se

Sorry about being so unclear, I thought you might be a member of the group in question. Actually, it is quite the opposite, he keeps saying that you shouldn't take a lens apart without having sophisticated equipment to collimate the lens when putting it together again, as well as considerable experience using the equipment, unless you want to have a clean but expensive paperweight. He thinks that if you just put it back together again the optical performance will be terrible. I wouldn't know, I haven't tried. I'm not sure I believe that companies like Minolta who made thousands of lenses wouldn't have worked out a way to make the optical elements self-aligning or something. It sounds like a lot of expense for a manufacturing process for consumer items. Anyway he claims to have years of experience designing stuff for spy satellites or something, however that might relate to commercial camera manufacturing. /Jonas On 8/13/2010, ard at p850ug1.demon.co.uk (Tony Duell) wrote: > >Well, if he's suggesting spaying soemthing into the lens (yes, I have >seen that suggested!), I certainly disapprove. If he;'s suggesting >removing the optical elemenets and applyuing solvent/lubricantmix to the >mount, then that's slightly better, but IMHO that's a method used by >people who can't handle tools and small parts properly, and if you're not >careful, it simply shifts the gummy lubricant, etc, elsewhere where it >will cause toruble lateer. I really do prefer to clean each part separately. > >-tony >

15 years, 7 months

Some DEC stuff on Ebay

by dave＠mitton.com

FYI: I have listed the following on eBay: Seller name: olebgamer - VT320 Terminal - VT220 Terminal - DECmodem V32 DF-296DA - 2 LK250 Keyboards Dave.

15 years, 8 months

Terminals.

by bqt＠softjar.se

Dave McGuire <mcguire at neurotica.com> wrote: > On 8/12/10 9:39 PM, Richard wrote: >>> >> DEC's terminal business was a shell of its former self back when the >>> >> VT420 was introduced, so it may be true. >> > >> > Maybe I'm thinking of the 240 instead? Does the 420 do graphics? > > AFAIK the VT420 supports Sixel, but not ReGIS. No. The last graphic terminal was the VT340. The VT420 don't support any graphics, unless you count the user defined font as graphics. Graphics implies either SIXEL, ReGIS or both. Actually, I've never seen any terminal that supports sixel but not ReGIS, however, several printers is of that inclination. (Although I'm sure someone will now recall some terminal that do sixel but not ReGIS just because I wrote the above... :-) ). Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

15 years, 8 months

NEC parallel to scsi host adapter

by chrism3667＠yahoo.com

part # is CDINT339 it allows you to plug in a SCSI device, and use your (parallel port) printer at the same time. Are drivers required? I remember Mike Brutman had one or something similar. He used it to drive a zip drive on a Peanut IIRC. Can anyone inform? Thank you kindly. The possibilities this item opens up are truly infinite. I can barely contain myself.

15 years, 8 months

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