test-drb March 2008

test-drb@ccmp.vtda.org

209 participants
369 discussions

by tiggerlasv＠aim.com

Usually, when I need a template for a DB25, DE9, or whatever, I just dig in the junk box for an old PC-type serial bracket. You know, from back in the day when the serial ports were in one of the blank spots for empty card slots, instead of being on the motherboard itself? Naturally, I'd prefer a punch myself, but as everyone agrees, they are kind of pricey. Fortunately, I've never really needed one that often, that I couldn't deal with using a nibbling tool. Depending on how you're planning on mounting it, the hole may or may not need to be perfect. If you're putting the D-connector BEHIND the panel / chassis, then you'll want a nice, neat opening. Although it's not as pretty, you can cut a rectangular opening with a screw-hole on each side, and mount the flanged portion of the D-sub on the OUTSIDE of the chassis. If you're careful, the metal frame of the D-sub will cover up any imperfections in the size/shape of the opening. And lastly, the "down and dirty method" is to cut a 3" x 1/2" rectangular opening, and use one of the afore-mentioned PC brackets from behind for mounting. I know. . . not pretty, but sometimes handy when working on a chassis with existing knock-outs/holes which need covering anyway. T

16 years, 4 months

32 sector 8 inch floppies

by jeffj＠panix.com

I just found a box of about 15: 8 inch floppies 32 sectors (hard sectored) Double Sided Single Density. Some are TDK F1-H Any takers? I'm in Elizabeth (central) NJ: they're free if you can pick them up!

16 years, 4 months

motorola boards

by pichotjm＠free.fr

Hi Alain! I have a lot of document describing the Exorcizer, with complete drawings, software, firmware... I still have a complete machine (a wrapped clone, i designed in this old time! two versions: one with 64k cmos RAM, and one 64k with DynRam) I knew very well 6800, 6300, 6801, 6301, ... In that time i created a real time emulator for these uP. But the system is old and needs to be restored. (I have a lot of spare parts, including 4 8" floppy mechanisms) . I intend to publish the story of this home brew computer, but i need time... (CPU, terminal, graphic printer, digital cassette, floppies, magnetic card reader B7400, Eprom prog) This machine is aslo able to run original OS9 with a 6809/6309 cpu. I have doc, 8" floppies, listings... too much matter... that needs to be sorted. Follow-up in french? Still in Bordeaux? Have a nice day! JMP

16 years, 4 months

Tektronics 4051 collection -- on craigslist in austin, texas, usa, earth

by frustum＠pacbell.net

Full text of the message, although the listing also contains a scan of a manual cover: My dad bought & used the 4051 series computers for many, many years, and accumulated several 4051 computers, peripherals, etc. He bought his first one in 1976, it was an amazing computer! Believe it or not, he was still programming the beast until about 3 years ago. So several of these computers still work. These things are RARE as hen's teeth now, and he has a lot of parts, even a screen for one that is new-old-stock still in the box (this is the computer that had the cool vector graphics screen!). I don't have pictures yet, but will get some. I want $2000 bucks for the whole collection of stuff. great find for a collector/tinkerer, as these don't show up very often. cash only, no checks. http://austin.craigslist.org/sys/604555003.html As the URL says, this is in Austin, Texas. $2000 seems kinda rich to me, but maybe to someone on this list it is worth it. I watch austin craigslist frequently and vintage computer gear doesn't show up all that often. I am not the seller; I don't know the seller; do your own vetting. Sorry, I'm not available to pick this up and ship it to a non-local buyer. Contents may settle during shipping. Your mileage may vary.

16 years, 4 months

D-shell hole punches?

by technobug＠comcast.net

On Tue, 11 Mar 2008 15:24:53 -0400 (EDT), der Mouse wrote: > I'm looking for D-shell hole punches, for DB and DE shells, and > possibly DA as well - Greenlee is the name I know, but I daresay > others > make them too. [...] > > Any suggestions? I've gone a bit of different route than the use of punches and nibblers - the former being too expensive for an occasional job and the latter too much of a pain. I use a spiral cutter and a template. I picked up a cheap spiral cutter from my neighborhood China Town store and modified it by adding a template follower to the head. I generate the template on a cad program, expand it twice needed and print onto card stock which I then hand cut. I use this template to cut the final template in plastic. Drill a hole at the cut-out site, clamp the template on the target piece and cut away. You should ensure that you get a metal cutter if you are doing steel or aluminum (aluminium). I found that taking two steps to generate the template results in a much better result. My cutter was bought on sale for under US$ 20 for a one-off job and kept around and modified when I ran into a situation that needed a odd shape cut-out. A good cutter will run under US$ 75 and the bits are on the order of 5-10. I've used it to do D-holes for BNCs and power cords, connectors, as well as many other openings such as for fans. CRC

16 years, 4 months

HP-21MX bootstrapping?

by Tim＠Rikers.org

ok, been meaning to actually run something more than the little assembly test apps on my HPs. How do folks bootstrap systems? I've got 2 working HPs (HP-2108A and HP-2112A) and HS-TERMINAL (ie HP-12531B) and I can get lights to light up with a 2400 baud connection and this snippit running: 0001* set to TTY I/O number 0002 00011 SC EQU 11B 0004 00040 ORG 40B 0005 00040 106700 LOOP CLC 0 Turn off I/O interrupt system 0006 00041 060051 LDA TTYIO Load A-register with control word 0007 00042 102611 OTA SC Output control word 0008 00043 103711 STC SC,C Set control, clear flag 0009 00044 102311 WAIT SFS SC Wait for flag 0010 00045 024044 JMP WAIT Loop till ready 0011 00046 106511 LIB SC Input data word 0012 00047 106601 OTB 1 Output data word to switch register 0013 00050 024040 JMP LOOP Next char 0014 00051 160000 TTYIO OCT 160000 TTY input and print control word LOOP 000040 01/0005 -- 01/0013 SC 000011 01/0002 -- 01/0007 01/0008 01/0009 01/0011 TTYIO 000051 01/0014 -- 01/0006 WAIT 000044 01/0009 -- 01/0010 4 symbols 14 lines assembled, 10 words generated 0 errors, 0 warnings (also online as http://rikers.org/hp2100/ttyin.lst) so what's next? Is there a tape loader for use over a 12531? Also, I'm using a modified version of the perl assembler. I'd like to actually use the native HP assembler under SIMH. The HP / CHM agreement should allow for at least this much bootstrap information to be shared. I'm happy to put up bootstrap instructions and tape images if someone can provide them. I don't have any other peripherals tested out yet. Not sure why my real paper tape reader is not working yet. My paper tape punch is a long ways >from working and it's not HP equipment anyway. I've got tape images that work in SIMH like the HP-Basic. Just want to see these work on real hardware by loading them over a serial line. There are quite a few HP collectors out there. How do you folks boot up your hardware? ok, I could get an HP-7970 9 track, but I don't have that either. It would seem useful to be able to bootstrap any given tape over serial. I know it's only 2400 baud, but just about every HP collector should have the needed hardware. :) Help me out! PS: Some nice list owner promised to get me a CD full of stuff to get started, but alas, I'm afraid my process is never getting scheduled. Perhaps I need more of a real-time OS. -- Tim Riker - http://Rikers.org/ - TimR at Debian.org Embedded Linux Technologist - http://eLinux.org/ BZFlag maintainer - http://BZFlag.org/ - for fun!

16 years, 4 months

Morrow documentation

by g-wright＠att.net

-------------- Original message from Al Kossow <aek at bitsavers.org>: -------------- > CHM received a bunch of George Morrow's engineering documentation yesterday. > Is there anything in particular from MD that hasn't already been scanned that > people > are looking for? > > There are a few odd things, like Adaptec IC data sheets, and the FDC-3 > schematics > that I've found. > > 2 systems Anything on the "Decision I" S100 system would be nice. I have not looked lately. A few years back someone connected to his stash was going to send me the info on these. Never did happen. They were a S100 bus system, but had non standard things like serial IO on the mother board with lots of jumpers. The Morrow portable. The one I have is just a Micro Decision in a Compaq Portable type box with a built in monitor. a little smaller in size though . - Jerry

16 years, 4 months

replacing failed components question causal or coincidental repairs

by lynchaj＠yahoo.com

On Sun, 9 Mar 2008, Andrew Lynch wrote: > I think repairing old computers is just like any human endeavor - it is > flawed and sometimes I follow incorrect logic and/or misdiagnose before > finding and fixing the real broken part. Sometimes good parts get > mistakenly identified as bad. That's life and if a part falls under > suspicion I am likely to just replace it just to test the theory, right or > wrong it gives information and vital clues. Anything labeled "suspect" is > pulled aside and labeled as bad regardless. > These parts are cheap and plentiful enough that if a few good ones get > trashed in the process of fixing an old machine I consider it a worthy > investment. Probably I am tossing some good parts occasionally but it is > worth it time wise to take the chance and maybe find the root cause. Were I > more skilled technician maybe I could fault isolate with more precision and > just fix exactly what is broken but this is just a hobby and I do not have > the time/experience to get more precise. Never discard the old parts, nor charge the customer, until the actual defect is found. Any reason to NOT plug the suspect Z80 back in and see whether the problems follow the chip v coming and going from other "random" acts? -----REPLY----- Hi Fred, Yes, I agree. I always "tag and bag" discarded parts from vintage computers I repair. "Tossing" was a poor choice of words. It means tossing them into the box of tagged baggies of suspect/broken parts. Since I am the owner I don't need to worry about charging anyone but I agree with the sentiment. Especially if this were a business I would not feel comfortable releasing the system unless I had firm evidence of root cause and not some coincidental fix. However, that is the dilemma. How to establish what exactly is the root cause without endangering the original piece of equipment? I would like some independent verification if possible. Everytime you touch or make a repair to an old computer there is a risk of unintended damage. Yes, I could swap the questionable components back into the system but I am very reluctant to "screw around with it" once it is working. I dislike using the restored piece as test equipment. Generally speaking, once it works reliably, I leave it alone until there is reason to attempt more repairs. I have found it is very easy to accidentally break things. That is why I rarely ever clean the boards or do anything to them other than the bare minimum to make them work again. One concern about swapping possible bad parts into a working system is that they could induce another failure and start the repair cycle all over again. What would be ideal is some sort of test equipment I could plug a bad part into and check to see if it is good or not. I can do that with EPROMs and apparently there are TTL chip testers like the TOP2049 which provide 74LSxxx testing. How do you test a LSI component like a Z80 CPU, PIO, DMA, or DART? Short of plugging it back in and hoping it doesn't cause more problems. I am an engineer by education and practice but self taught as a technician. Sometimes I wish I had more experience in these matters or at least took some coursework on how to diagnose and repair equipment. Thanks for your advice! Andrew Lynch

16 years, 4 months

D-shell hole punches?

by mouse＠Rodents.Montreal.QC.CA

I'm looking for D-shell hole punches, for DB and DE shells, and possibly DA as well - Greenlee is the name I know, but I daresay others make them too. The major constraints: (a) the seller must ship to Canada; (b) the seller must take phone or fax orders - I can tolerate looking for things on the Web, but I will _not_ pay over the Web; (c) they must be decent quality - no cheap knockoffs that break along about the fifth time you use them (as Tony, I think, put it, I'm not rich enough to buy cheap tools). There is no need to be especially fast to use; if it takes a minute or two to position the pieces and crank a bolt down with a wrench or something, that's OK. Of course, I'd like them to be inexpensive too, but "inexpensive and not cheap" is a combination I don't really expect to find. If I'm asking for a pony, I'd also want the vendor to be in Montreal or Ottawa, but that's, well, asking for a pony. :) Any suggestions? /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

16 years, 4 months

In which I further expose my ignorance: What is this electronic component?

by tiggerlasv＠aim.com

Well, my first guess would be an inductor of some sort; TDK produces a line of inductors with that basic outline. It looks like exposed enamel wire and wax on top. Although I am confused by the outer covering, which appears to be indicating polarity. . . Bizarre. . . T

16 years, 4 months

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test-drb March 2008