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101090 discussions

by henk.gooijen＠hotmail.com

Hi all, I wanted to sell a big blinkenlight panel, because I realized I will never find the time for again another project ... Auction number 170539265245 shows a few pictures (auction is ended). I would like to add more info before re-listing the front panel. thanks, - Henk.

15 years, 7 months

Bell & Howell II+

by mloewen＠cpumagic.scol.pa.us

Does anyone have a good feel for the current market value of a Bell & Howell II+? Model is A2S1016B, serial #A2S3-000985 with disk drive, paddles, manuals, cassette player, cassettes and floppies. Unknown working condition. Installed boards are ROM Card, Disk II Interface, plus a Sup "R" Mod II. This isn't mine, but the owner contacted me asking what it might be worth. I haven't paid any attention to Ebay prices on these, but it looks like a generic Apple II+ might fetch $150 or more. Mike Loewen mloewen at cpumagic.scol.pa.us Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/

15 years, 7 months

Help resurrect my Xerox Alto

by tim＠tim-mann.org

Probably not too useful a remark, but I remember from years ago when we had some Xerox Altos at the Stanford computer science department that the disk drives were very prone to head crashes. We were instructed to never attempt to remove the disk pack under penalty of flogging (or some less colorful words). So, I hope once Nick gets the voltage problem fixed, he's not disappointed to find out that disk doesn't work anyway. :-/

15 years, 7 months

MicroVAX 2000 ROM placement question

by ethan.dicks＠gmail.com

Hi, All, I've been trying to dust off a MicroVAX 2000 for VCFmw, and so far, all I've accomplished is literally getting the dust off. This unit was one I tried to install the SCSI-enabled patched boot ROMs in some time back. I _thought_ I had arranged the original ROMs in the same pattern, but it's possible with all the swapping, I got some mixed up. I have checked (and re-downloaded) all the ROMs I have - one factory set (23-092E7-00 through 23-095E7-00) and one patched set. Cross-checking with the Technical Reference manual (EK-VTTAA-TM-001) from Bitsavers, I have verified that all ROMs have reasonable contents in the first few bytes (there are three signature bytes, among other things). No matter which set I have installed, I cannot get the console to respond with the self-test info. Does anyone have a photograph of a KA410 board where the labels on the ROMs can be read? Alternately, does anyone have any docs with part numbers? I'm reasonably certain that the underlying hardware is functional and that I just need to re-install the ROMs correctly. Yes, I could try the lucky-dip method, but one of the ROMs is rather difficult to pull (owing to the memory interface connectors), and I'd rather not break a pin off while sequencing through a dozen chip swaps. I'd like to _know_ what goes where before I proceed (especially if I am wrong and I _do_ have a hardware fault). I don't have any video cables handy, but in case it does come down to testing with a tube vs a console terminal, I have a four-plane video interface in addition to the mono frame buffer all KA410s come with. I had just thought that it would be easy enough to use a BCC08 console cable and go from there (it's worked before). Thanks for any tips or pointers, -ethan P.S. - I've been delving into the guts of the machine deeply enough that I'm musing about what it would take to make a 16MB memory board that didn't respond in the lower 2MB (to work with the on-board memory). Static would be easy to interface, but the KA410 _does_ generate and pass along refresh signals, so something with 30-pin or 72-pin SIMMs shouldn't be that hard to whip up. I'm only considering it because my largest memory board is 4MB, and the current prices for an MS400-CA (12MB DEC board) are more than I'm personally willing to pay - I'll do without first (which is what I'm already doing ;-) P.P.S - this would probably all be moot if I had a SCSI-based MicroVAX slab of some sort, but I just haven't been in the right place at the right time. Perhaps some DEC gear will make an appearance at the VCF...

15 years, 7 months

Any design "gotchas" with the Xicor X2864 EEPROM?

by ethan.dicks＠gmail.com

Hi, All, I'm going through a box of older ICs and ran across a few X2864s. I know they are 64Kbit JEDEC EEPROMs, but what I don't know is if there are any odd issues with them. I found a datasheet that's mostly in Japanese - I do happen to read some Japanese, but I'm far from fluent. I'm mostly curious about in-circuit programming. I know a lot of newer hobby-type projects use different families of EEPROMs and that some devices can only program certain ones. What I don't know is how that relates to something as old as the X2864. I can probably program these in a standalone device programmer and potentially have to build a pin-swabber socket for a 2364 (or even 2332 for a PET), but I'd like to know if I'm opening a can of worms before I begin. Thanks for any warnings of pitfalls ahead. -ethan

15 years, 7 months

Mass spectrometers etc

by jonas＠otter.se

On , 15 Sep 2010 20:30:26 +0100 (BST), ard at p850ug1.demon.co.uk (Tony Duell) wrote: >Subject: Re: Mass spectrometers etc >To: cctalk at classiccmp.org >Message-ID: <m1Ovxgb-000J4BC at p850ug1> >Content-Type: text/plain > >> You need to find a diffussion pump. These will get you down to > The French guy used a rotary vane pump and a molecular pump, which you could probably make yourself at home (he did). The rotary vane pump shouldn't give you any problems, and for the molecular pump you only need an old motor capable of 24000 rpm without breaking up, and some careful machining :-) A spot of high vacuum grease, a few seals etc and you are all set. The finished set up isn't particularly large either. No oil in the molecular pump either... /Jonas >Indeed I do (My father spoet most of his working days on high vacuum >systems., I think I'd head ofa 'diff pump' before I even went to school... > >OIl, from choice. Mercury vapour, even inside a vacuum system (and some >will, alas, end up in the backing rotary pump) is not something I >particualrly keen on.... > >There is the minor problem of 'where the heck do I set up a vacuum >system, along with all the other things I am working on' :-) > >-tony >

15 years, 7 months

Classic computing on the rise !

by jdr_use＠bluewin.ch

http://www.bbc.co.uk/news/technology-10951040 show how old computers are used toteach programming.

15 years, 7 months

HP 9825 refurbishing

by dfnr2＠yahoo.com

Hello all, I bought one of the HP 9825's that Marvin recently posted here about (via VCM auction). It's a 9825T and seems to work perfectly, along with an HPIB interface I bought off Ebay. Of course the case needs cleaning and there is a penny-sized chip from the corner of the bezel, so I've got the whole thing disassembled, and am now in the process of rebuilding the chipped bezel corner with JB-weld. Next step is to repaint the case, then replace the at-risk PSU caps, refurbish the tape drive, clean the keyboard, etc. The unit is beautifully engineered, by the way. Some questions for the group: 1) Does anyone have a suggestion for the best paint to match the original color? If I can find a close match, I'll just tape over the legends on the bezel, and paint around them. If I can't get a good match, I still may do the same thing, or I'll just paint the whole thing, and then print out some decals on a color printer to match the original legends. Or, if anyone here has a better suggestion, I'd love to hear. Any suggestion for type of paint? I found a can of Rustoleum brand almond-color satin finish enamel spray-paint. Is that a good choice, other than wrong color? I also just bought an HP 87 on Ebay as well, so I'm hoping that whatever I learn here, I can apply to refurbishing the 87 as well. 2) While the unit is completely disassembled, are there any hacks, mods, upgrades, etc. that I may want to know about before I put everything back together? 3) I would like to use this in my home lab, so I was hoping to find a way to store programs without using the tape drive or a disc drive. Is anyone there moving data between the 9825 and a PC? Can some of the utilities on hp9845.net be used to interface with the 9825 as well? This would be icing on the cake, since it would be shame to let such a nice machine go unused. However, I do have the Prologix GPIB interface with PyVISA/Scipy/Numpy, Thanks for any input, Dave

15 years, 7 months

converting RGBHV to RGBS -- anyone have 74HCT86's?

by keithvz＠verizon.net

I've got a chinese converter(from ebay, recommended by a few here) that will take 15khz RGB video with composite sync and spit out VGA at ~32khz so a regular monitor can be used to display the signal. http://cgi.ebay.com/RGBS-CGA-EGA-YUV-VGA-converter-1-output-arcade-game-/25… The seller claims (and spec sheet does indeed look this way) that the RGBHV input must be 30khz+, but the RGBS input supports down to 14.5khz. I'm attempting to use this with my amiga, which sends out separate H and V SYNC signals but at 15.7khz. I found this schematic http://www.epanorama.net/circuits/vga2rgbs.html The simple VGA to RGB+CSYNC adapter TTL (which appears the same as the "Separate Sync to Composite Sync Adapter") I intend to build this, and see if this does the trick for me. This sound like a reasonable plan? Anyone happen to have a few 74HCT86's lying around? I can order them online but because they are under $0.50 a piece, and I'll likely have to pay a minimum order size fee plus S&H. Seems a waste for a dollar's worth of items. Thanks Keith in Pittsburgh, PA, USA

15 years, 7 months

Mass spectrometers etc

by jonas＠otter.se

On Fri, 10 Sep 2010 20:02:09 +0100 (BST), ard at p850ug1.demon.co.uk (Tony Duell) wrote: > >Oh, I have one, but it's only a little 1cm radius one, designed mainly >for detecting the helium peak when looking for leaks. What I don't have is >a suitable vacuum pump (yet...) > You might be interested in this site (sorry it's a Web site with pictures and so on, some of it will probably be readable using Lynx, and it's in French to boot, I'm sure it would interest you however): http://paillard.claude.free.fr/ He makes his own triode valves (or tubes, for those of us who speak the other language known as English ;-) ) and in order to do that he has designed and built among other things his own high vacuum pumps. I'm sure you would be able to make one like his. /Jonas

15 years, 7 months

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