test-drb November 1999

test-drb@ccmp.vtda.org

211 participants
749 discussions

by cvisors＠CarnageVisors.net

Hi all, I have been lurking on this list for the last few days, and I thought I will introduce myself... Well I'm 25 or so ,living in australia, and I have aquired a number of DEC MicroVAX IIs. one of which is missing enough cards to render it useless...(oh well such is life.. I am slowly trying to get at least one of these machines working, and I hope to have one of them working soon. What I was wondering, is I have a lot of cards for these machines, and was wondering if anyone would be able to help me identify them and tell me what would be the best way to order them in the Q-bus, and help me with setting the adresses on the cards which nees such settings. I realy want to get one of these old beasts going, and hopefully get netBSD running on them. Thanks Benjamin Gardiner

25 years, 1 month

11/34 & Cool stuff, but what is it? (Q-bus gear)

by CLASSICCMP＠trailing-edge.com

>> >Then the other interesting card was a national instruments 179055-01 which >> >has an Intel 8291? on board (date code of either '84 or '91). Sort of a >> >weird 40 pin connector that goes to what looks like the old GPIB connectors. >> >> Yep, it's a IEEE-496 interface. >A what? Is this some varient of IEEE-488, or something totally different? Whoops, wrong IEEE number there :-). I meant IEEE-488, as you figured out. I believe that the confusion was caused by IEEE-696, aka "S-100"... -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

25 years, 1 month

11/34 & Cool stuff, but what is it? (Q-bus gear)

by CLASSICCMP＠trailing-edge.com

>So I'm trying to collect the stuff I won at a recent auction, the most >unexpected deal was the PDP 11/34 for $10 with the DEC Cassette tape >transport. Its dirty and grimy but it seems complete. I could satisfy my >desire for a Unibus -11 for now (and at a cost I appreciate :-) > >Anyone have any info on the DEC Cassettes? TU-?? TU-60. > they are standard audio >format cassettes and one of the cassetes that came with it claims to have >PAL, EDIT, and LINK on it. This will be fun to explore. Sounds like the standard cassette tape development tools. >Then I bid on a rack of "junk" which was topped off by a Kennedy 9610 tape >drive. I bid on it because the tape drive had what appearred to be a 50 pin >cable going to a Q-bus card marked Emulex. In fact it was _two_ 50 pin >cables and the Emulex card is labelled QT1310401-00-REV E. On the firmware >the label reads QT1310201-02 REV K. What is it? The QT13 emulates either a MS: (TS11) or MU: (TMSCP) type drive and talks to tape drives with the Pertec-formatted formatted interface. > I was hoping it was a SCSI controller but two connectors? Not SCSI, it's Pertec formatted. >Then the other interesting card was a national instruments 179055-01 which >has an Intel 8291? on board (date code of either '84 or '91). Sort of a >weird 40 pin connector that goes to what looks like the old GPIB connectors. Yep, it's a IEEE-496 interface. >Final question, how do you "de-rack" the 11/34? I can get it to rotate but >I can't get it to let go and come out of the rack. I don't want to >transport it in the rack so... There were several different styles of chassis-mount slides on the 11/34 series. Are your slides shiny metal or are they grey? If they're shiny metal, look for one shiny wobbly lever on each side that has to be pressed in to release the catch. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

25 years, 1 month

Schottky diode Question.

by edick＠idcomm.com

Well . . . MY DMM doesn't read the DIODE the same in both directions. If it reads the same when the DMM is in DIODE TEST mode (the only one which is really meaningful) it should read the voltage across the diode. If it's the same in both directions, AND NO OTHER CONNECTED Devices are present, it's not a diode. In your case that probably means that it's broken. If you're measuring it in situ, the other components in the circuit are probably playing a role. I don't have the data book on that diode here, so I'm guessing it's a rectifier, and therefore has a forward voltage on the order 0.275 volts. (SCHOTTKY diodes are preferable for rectifiers in portable devices because they (1) require less voltage overhead, and (2) don't generate as much heat. Be sure you know what you're measuring! I've never had a battery on my notebooks go bad, so I don't know how they behave when they do that, but I've seen some sensor circuits used in turning the system on which don't work when the battery is in "deep discharge" as it might be if it was left on and became "empty" enough that the charge circuit sees it as a short and defends itself by shutting down. Try an external charger for the battery. If that doesn't charge the battery, then charge up a 7500 microfarad capacitor to about 75 volts and discharge it through the battery, observing correct polarity. That may blow out any cilia which may be causing a cell to behave as though it's collapsed. good luck! Dick -----Original Message----- From: jpero(a)cgocable.net <jpero(a)cgocable.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Tuesday, November 02, 1999 4:28 PM Subject: Schottky diode Question. > It might work better if you use an unused gate or some such. Phantom often > has numerous loads on it, so you could consider a pair of OC gates if > they're available. Otherwise, a SCHOTTKY diode should suffice, since its > forward voltage isn't enough to confuse any other device into missing the > LOW on the PHANTOM line. I have measured resistance both ways, it becomes less of a diode as I go higher in resistance scale on my DMM, around 20K and up I read like a piece of 100 ohm resistor both ways but reads fine on diode mode. BTW: these are 1N5822. I'm working on a bondwell 486NC2 notebook seems to have power problem. Even with batteries unplugged, charge LED lights up same time as power lights up when I plug power brick in. Sometimes I can get hint of action and just once got computer to boot up for few seconds then dies. What gives? Wizard

25 years, 1 month

schottky diode again..

by edick＠idcomm.com

Its not a bad idea to test a diode at the current for which it was designed. If you want to do that, it won't be a waste of your effort. However, I would guess it's time not well spent to continue fiddling with the diode you've apparently shown has too much reverse leakage to be of use. I'm persuaded (perhaps incorrectly) that your diode is from a rectifier or switching circuit associated with the battery charging/power conversion process. If it is, then it's probably a rectifier and not a signal diode. You can probably replace it for less than a dollar and get several spares in the same operation. Dick -----Original Message----- From: jpero(a)cgocable.net <jpero(a)cgocable.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Wednesday, November 03, 1999 5:48 PM Subject: Re: schottky diode again.. > Date: Thu, 4 Nov 1999 00:10:57 +0000 (GMT) > Reply-to: classiccmp(a)u.washington.edu > From: ard(a)p850ug1.demon.co.uk (Tony Duell) > To: "Discussion re-collecting of classic computers" <classiccmp(a)u.washington.edu> > Subject: Re: schottky diode again.. > Have you tried reading the 'manuals' for most modern meters (or other > test gear)? They're useless for actually telling you what the instrument > is doing. At one time, such manuals contained schematics, simplified > schematics, circuit descriptions, etc. Not any more :-( Tony as usual is right. I don't read those modern manuals these days. Except skimming for few areas just to be sure. > > Surely the sort of person who buys a multimeter is also the sort of > person who can read/understand a schematic. So the lack of such > information is something of a puzzle to me. That DMM is built by me in kit form and calibrated it for voltage and current. Good as any normal DMM should do. Same with ESR. no calibrating required. Zeroes when shorting and press the button twice. One push turns on ESR, when on and probes is showing low resistance or shorted together and pressed button again zeroes it to account for losses in internal circuits and probe wires. That ESR meter has real docs because it's kit and info that explains why can most of time can measure caps in circuit. Came from Dick Electronics (Aus) for about 40 US. The pot is only there to preset for voltage cut off to warn of low battery condition. > > For this reason, I _always_ test every feature of a new piece of test > gear, often in unconventional ways. I _will_ check diodes on resistance > ranges to see what happens. Often the lower resistance ranges _do_ > provide enough current to provide a useful test on diodes, and the > ability to do the check at more than one current sometimes picks up > 'rogue' diodes. Correct as I suspected by playing. My DMM actually shows better when I move from low res scales to mid to high ranges. I need to grab another meter to see what it do on my dmm. :-) Tony inpsired me to this! > > -tony > Wizard

25 years, 1 month

schottky diode again..

by edick＠idcomm.com

If you have a diode of any kind which behaves more as a resistor and less as a diode, i.e. it measures more or less the same in both directions, though differently on different settings on your DMM, I'd say it's broken. The reason for all the discussion about batteries is that a set of batteries for a typical notebook costs only a bit less than $200 for a cheap one, and it's useful to know whether the notebook works before buying a new battery pack. Most of them don't work with no battery at all, though some do. If there's something wrong with your diode and the diode is in the charging circuit, with behavior like you've described, it will discharge your battery and subsequently into deep discharge, which will permanently and irrevocably damage NiCd and NiMH batteries. A schottky diode is simply a diode. It has doping different from a typical silicon diode, hence has a lower forward voltage, hence dissipates less power than a silicon diode at the same current. If it has measurable resistance cathode to anode and anode to cathode which is about the same, it's no longer acting as a diode. Dick -----Original Message----- From: jpero(a)cgocable.net <jpero(a)cgocable.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Wednesday, November 03, 1999 3:30 PM Subject: schottky diode again.. Sheesh, that topic wandered off the diode discussion! Snip! The important thing I wanted to hear about is how schottky diodes reacts if good and what it's like when bad or sick on a DMM with different resistance scale settings used, diode test also seems says "good" but I know it's very low current also low voltage so that would usually not screen out sick diodes. That why I used resistance ranges just to be sure. Yes, I pull diodes and transistors out for checks to be sure. Ingore the battery thing please. I'm more concerned getting the notebook going. Thanks. Wizard

25 years, 1 month

Alphatronix == Viking

by cmcmanis＠freegate.com

Darn if Dan the Man didn't win the prize on this one. The Alphatronix board is a re-badged Viking SCSI board with some of their own firmware. Now to see if I can change its notion of identity.... --Chuck

25 years, 1 month

schottky diode again..

by sms＠antinode.org

> From: "Richard Erlacher" <edick(a)idcomm.com> > > If you have a diode of any kind which behaves more as a resistor and less as > a diode, i.e. it measures more or less the same in both directions, though > differently on different settings on your DMM, I'd say it's broken. I'd say you have a modern meter, and neither of you knows how to use it. The "diode" range on the meter is there because the other resistance ranges are not useful for testing diodes. Read the manual for the meter, or buy a curve tracer, or build a continuity tester from an old flashlight (two-cell preferred), or ... I'm curious. Have you tried the same family of (mostly misleading) tests on a known-good, plain-old silicon diode? > > From: jpero(a)cgocable.net <jpero(a)cgocable.net> > > ... > > says "good" but I know it's very low current also low voltage so that > > would usually not screen out sick diodes. The current and voltage for the resistance ranges are probably much lower, which is why the readings are so useless. (Repeat previous rant here.) > That why I used resistance ranges just to be sure. This must be some new meaning of "sure". There are some subtle defects possible in a diode which will not be revealed by the "diode" test on a multimeter, but that's almost certainly the best test offered by the meter. > Wizard Apparently a misnomer. ------------------------------------------------------------------------ Steven M. Schweda (+1) 651-645-9249 (voice, home) 1630 Marshall Avenue #8 (+1) 612-754-2636 (voice, work) Saint Paul MN 55104-6225 (+1) 612-754-6302 (facsimile, work) sms(a)antinode.org sms(a)provis.com (work)

25 years, 1 month

Items Added to Classic Computer Sale

by bill_r＠inetnebr.com

Today a number of additional items were added to my on-line sale, including a Tandy 1000, a Tandy 2000, Tallgrass hard drive, Tektronix scope, Beehive MicroB1 video terminal, and a Hazeltine 1000 terminal. Check it out at: http://incolor.inetnebr.com/bill_r/computer-sale.htm -Bill Richman (bill_r(a)inetnebr.com) http://incolor.inetnebr.com/bill_r - Home of the COSMAC Elf Microcomputer Simulator, Fun with Molten Metal, Orphaned Robots, and Technological Oddities.

25 years, 1 month

Victor series 1400 CRT tube display calculator

by bill_r＠inetnebr.com

I'm trying to restore a Victor series 1400 CRT tube display calculator, and wondered if anyone had any information about them. It's got a 3" or so green CRT display with masks for the numbers, and a big board full of mostly unmarked chips. It used to work fine, but one day it quit, and I have no clue why. It's just totally dead. Have checked the fuse, caps, etc. A schematic would be wonderful. -Bill Richman (bill_r(a)inetnebr.com) http://incolor.inetnebr.com/bill_r - Home of the COSMAC Elf Microcomputer Simulator, Fun with Molten Metal, Orphaned Robots, and Technological Oddities.

25 years, 1 month

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test-drb November 1999