test-drb December 2007

test-drb@ccmp.vtda.org

215 participants
420 discussions

CrayLink cabling prohibited on Origin 2000 deskside

by legalize＠xmission.com

OK, I found it: Origin2000 and Onyx2 Deskside and Rackmount Installation Instructions Document Number 108-0155-002 12/96 pg. 6-36 "Caution: You cannot install CrayLink interconnect cabling on a standalone deskside system because of power grounding requirements. The power differential between two interconnected modules should not exceed 500 millivolts; otherwise severe damage can result to boards and other components inside the chassis. The power distribution unit (PDU) inside the rack provides a common ground source for the modules. In addition, the groundstraps are installed on multirack configurations to help provide common grounding across the racks as described in Section 6.16" That seems about as blunt as you can get. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

16 years, 7 months

More bits for free [UK]

by classiccmp＠memory-alpha.org.uk

Hi, >> Philips CDD-462 External CD-ROM drive - boxed with manuals, >>software, 2 interface cards but no cable. > > Eeek. I never throught I'd see anyone else with one of those... I did wonder whether it was the same unit you mentioned recently when I dug it out. >....The service manial (yes I have it!), doesn't list some components >in the parts list, I think you're supposed to deduce what audio player >is much the same and get the bits for that! Is that normal for Philips? The only Philips service manual I currently have is the one for my old Philips BSB receivers, and that one is pretty darn complete. > Anyway, the cable is, I am pretty sure, straioght-through (DA15-P to >DA15-S).... That's what I figured, only reason I never made one up is that I never got around to playing with the unit. One of those things I was going to get around to "one day".... ;-) TTFN - Pete.

16 years, 7 months

Diodes [was: The 2N2/256-BSCP [was: Homebrew Drum Computer]]

by ajp166＠bellatlantic.net

> >Subject: Diodes [was: The 2N2/256-BSCP [was: Homebrew Drum Computer]] > From: Tom Watson <tsw-cc at johana.com> > Date: Sun, 23 Dec 2007 15:02:01 -0800 (PST) > To: cctech at classiccmp.org > >In a previous message, Allison <ajp166 at bellatlantic.net> said: > > >> Shotkey diodes are common. Aka 1n5711. Widely used in Rf and microwave. >> They are low capacitance fast switching with low threshold. >> >> Allison > >A couple of things here. There are TWO different things: >1) Yes, there are Schottky diodes as you have mentioned. They have very low >forward voltage drop and are the basis for a faster TTL series (74Sxxx/74LSxxx, >and probably others). Another attribute is that they switch fast. These are >very available. >2) The other type of diode is a Shockley (like the "co-inventor of >transistor"). These are 4 layer devices and behave similar to a neon bulb only >at a lower voltage, and without the glow. They have a high "trigger" voltage, >and a lower "sustaining" voltage that keeps the current flowing (look at how a >neon bulb "NE-2" works). I don't remember much more than that, but my high >school science teacher wanted to make up a storage array using them. This was >in the 60's, and we didn't have DRAM them, so it looked "interesting". I >suppose you could simulate them with a connected PNP/NPN transistor pair (as >mentioned here), or use a higher voltage to trigger and use an SCR (another 4 >layer device) and not connect the trigger lead. These went out of style long >ago I understand. In looking things up, I ran across this: >http://www.allaboutcircuits.com/vol_3/chpt_7/3.html >which explains things in great detail. Mixed them up. You can simulate that using two transistors. I've done that mant times as it's easier to have a few 2n3904/06s handy rahter than some part thats not unobtainium. The transistor equivilent is more flexible. Allison > >-- >Sorry, >No signature at the moment. > > > ____________________________________________________________________________________ >Looking for last minute shopping deals? >Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping

16 years, 7 months

Diodes [was: The 2N2/256-BSCP [was: Homebrew Drum Computer]]

by tsw-cc＠johana.com

In a previous message, Allison <ajp166 at bellatlantic.net> said: > Shotkey diodes are common. Aka 1n5711. Widely used in Rf and microwave. > They are low capacitance fast switching with low threshold. > > Allison A couple of things here. There are TWO different things: 1) Yes, there are Schottky diodes as you have mentioned. They have very low forward voltage drop and are the basis for a faster TTL series (74Sxxx/74LSxxx, and probably others). Another attribute is that they switch fast. These are very available. 2) The other type of diode is a Shockley (like the "co-inventor of transistor"). These are 4 layer devices and behave similar to a neon bulb only at a lower voltage, and without the glow. They have a high "trigger" voltage, and a lower "sustaining" voltage that keeps the current flowing (look at how a neon bulb "NE-2" works). I don't remember much more than that, but my high school science teacher wanted to make up a storage array using them. This was in the 60's, and we didn't have DRAM them, so it looked "interesting". I suppose you could simulate them with a connected PNP/NPN transistor pair (as mentioned here), or use a higher voltage to trigger and use an SCR (another 4 layer device) and not connect the trigger lead. These went out of style long ago I understand. In looking things up, I ran across this: http://www.allaboutcircuits.com/vol_3/chpt_7/3.html which explains things in great detail. -- Sorry, No signature at the moment. ____________________________________________________________________________________ Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping

16 years, 7 months

VCM offline?

by evan＠snarc.net

Rumor sez the VCM is getting a software upgrade... -----Original Message----- From: "Michael B. Brutman" <mbbrutman-cctalk at brutman.com> Subj: VCM offline? Date: Sun Dec 23, 2007 2:08 pm Size: 212 bytes To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Sorry about that last message .. bad clicking on my part. I'm having trouble getting to Sellam's marketplace site (http://vintagecomputermarketplace.com/) - was there an announcement that I missed? Mike

16 years, 7 months

The 2N2/256-BSCP [was: Homebrew Drum Computer]

by cclist＠sydex.com

On 23 Dec 2007 at 12:00, cctalk-request at classiccmp.org wrote: > Shotkey diodes are common. Aka 1n5711. Widely used in Rf and microwave. > They are low capacitance fast switching with low threshold. Not Schottky diodes, but *Shockley* diodes, a close relative of a diac. Genuine ones, circa late 1950's are very hard to find: http://semiconductormuseum.com/PhotoGallery/PhotoGallery_Shockley4E30. htm Schematic symbol looks like the number "4" with leads coming out of the top and bottom. Here's an application using some in an audio power amplifier: http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=3979 Sometimes also called a "transistor diode" and once intended to replace the 3-terminal transistor. Cheers, Chuck

16 years, 7 months

OT sockets for Nixies

by tpeters＠mixcom.com

This is off-topic in terms of the industry involved, but not too far off in the time period this stuff dates from. I've got some very nice, rather large Burroughs nixies- 7971 types. They're 4.8" high, "British flag" display which looks to be 2.5" high inside the glass. They have 15 segments each-- 14 in the alphanumeric display part of the tube and one sort-of cursor, an underline character with the ends bent downwards. I hear one can dismember D-shell connectors to get some sockets to solder to a pc board to connect to these. But my problem is driving them. Anyone know a good way to drive these, four or six of them in an array? I need 170 volts, 21ma all cathodes, between 4.0 and 6.0ma any individual cathode. I was thinking of a pic at each tube, sort-of a character generator that would take an ascii code and drive the right segments. Some sort of escape code would let you send 16 bits to be interpreted literally, i.e. turn on the literal segments corresponding to the bits set, for more fanciful displays. -T ----- 994. I have not failed. I've just found 10,000 ways that won't work. -- Thomas Edison --... ...-- -.. . -. ----. --.- --.- -... 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

16 years, 7 months

VCM offline?

by mbbrutman-cctalk＠brutman.com

Sorry about that last message .. bad clicking on my part. I'm having trouble getting to Sellam's marketplace site (http://vintagecomputermarketplace.com/) - was there an announcement that I missed? Mike

16 years, 7 months

VCM offline?

by mbbrutman-cctalk＠brutman.com

Is anybody else having problems getting to

16 years, 7 months

Zilog system 8000

by frustum＠pacbell.net

A friend and former coworker, Terence Tanaka, emailed me yesterday saying: "I used to work at Zilog and have some tapes, printout and eproms for the System 8000. I don't want to keep it but hate throwing it away. If it can find a good home, I'm willing to ship it." If you are interested, please contact me, not the list, and I'll forward your email address to Terence. In case more than one person wants it, please include a description of how this might use this. Preference goes to someone willing to publicly archive the information, secondarily to someone who has a system that could use these items, tertiarily :-) to a pack rat who will keep it intact and in good condition until they finally come to realize that they didn't need it and will pass it on to the next guy. Eventually it will get in the hands of someone with the time to archive it. PS, the System 8000, as you might expect, was based on the Z8000. PPS: reply to me, not the list!

16 years, 7 months

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test-drb December 2007