test-drb February 2000

test-drb@ccmp.vtda.org

162 participants
585 discussions

Poor contact repair (was: Re: The pure *hell* of restoring a PDP-8/S desktop.

by mtapley＠swri.edu

Allison wrote: >Warning... Silicone grease is persistant stuff and one on what ever >it's very hard to remove. So a board that requires soldering need >that done FIRST then wipe the fingers with a thin film. True. The Contamination Engineer on the NASA program I'm working on swears by "Simple Green", a widely available (grocery-store) detergent, for removing silicon grease. She recommends the clear, unscented version of it, which she uses on our flight hardware. She still hates silicone greases/oils/release agents, though, because it *is* hard to get off once it's on, and it does tend to flow/spread all over anything it's put on. - Mark

24 years, 4 months

free machines in Woodbridge VA

by yakowenk＠cs.unc.edu

BTW, if you live in the Woodbridge area, and would be willing to help in the rescue by picking up, packing up, and shipping things to people who are interested but not proximal enough, drop me a line. It seems safe to assume that interested parties will be willing to pay shipping costs, at least. (I'm a few hundred miles away, so I can't reasonably do it.) Thanks, Bill. > Date: Tue, 8 Feb 2000 15:49:42 -0500 (EST) > From: Bill Yakowenko <yakowenk(a)cs.unc.edu> > Subject: free machines in Woodbridge VA > > Hey all, > > Once upon a time, I wrote asking for volunteers to rescue some machines > in Woodbridge VA. There was a PDP-11/34 that got rescued, but there > is still a big pile up there that is headed for the scrap heap unless > somebody picks it up. Of course, the remainder is mostly PC > crap^H^H^H^Hstuff, but some of it is old enough to be of possible > interest. > > Let me know if you're interested. (The guy dumping this stuff really > would like it to find good homes, but he still doesn't want to be > overrun by dozens of requests, so I'm still trying to coordinate things.) > > Without further ado, here's the list brought back by our recon guy, > Al Corda <applause>. Some of it may be gone by now, but most is > probably still there: > > > ] As of today (1/10/00) items of interest I have identified > ] include the following: > ] > ] 3 or 4 Gen-u-ine DEC VT100s (some with keyboards! :-) > ] > ] A number of IBM XTs (Yeh, I know, but I included them for > ] completeness :-) > ] A number of IBM ATs (Just plain ATs, no AT370s or AT3270s (so far)) > ] > ] 2 Compaq Plus Luggables > ] > ] A bunch of LaserWriter II printers in various states of repair > ] A bunch of Spinwriter printers of various makes. > ] > ] 2 Photocopiers (1 Canon Npf-270, one Xerox (not certain of model)) > ] > ] A bunch of PC monitors, mostly monochrome or CGA (no VGA as far as I > ] could tell) > ] > ] A couple of cases of various PC software from the early 90's > ] (stuff like RBASE, etc.) > ] > ] 3 or 4 large _HEAVY_ units that on brief inspection strike me as > ] UPS (or line conditioner) units. No manufacturers markings were > ] obvious (but I wasn't going to try to turn one over. My back is > ] worth more to me than any UPS.) > ] > ] Piles of office telephones, Old modems, Various unidentifiable > ] electronic assemblies of dubious origin, Boxes and boxes of cables, > ] wire, etc. > > Cheers, > Bill. > > > PS. I've been _way_ behind on answering e-mail lately, so remind me > in your reply that this is time-sensitive, and that machines will > get crushed if I nap. :-/

24 years, 4 months

Product review websites?

by cfandt＠netsync.net

Hi group, I've been hunting for a new CD-ROM drive and a 4-6 Gig hard disk for a PC box. So far I've not found any decent websites who have *objective* reviews of these products between different manufacturers. For example, I _don't_ think I want another Creative brand CD-ROM as the one I put in my son's box died after less than a year. I can't spend too much $$ as I'm just getting back to work (finally) and am a bit dry, so low-to-moderate cost devices would be okay as this isn't a mission critical application. Reasonable reliability is an important factor (e.g., the thing lasts for 2+ years). Any thoughts? Please reply offline as this is definitely off topic. Many thanks for your wisdom! Regards, Chris -- -- Christian Fandt, Electronic/Electrical Historian Jamestown, NY USA cfandt(a)netsync.net Member of Antique Wireless Association URL: http://www.antiquewireless.org/

24 years, 4 months

Schematic capture/PCB design software

by edick＠idcomm.com

Well, the package I got from MicroCode was supposed to be a "full-up" version and after I called inquiring about the libraries, I was told "that's all there is, there 'aint no more" at which point I gave up on them. We all get attached to our tools, and I am not trying to pass any sort of overall judgment on their product. However, I do believe that the EAGLE package, though it is not terribly easy to learn either (takes about an hour plus the "easter egg hunt" for the various components and proper package outlines, particularly connectors and passives, the commercial version seems to be pretty adequate at a price about half that asked for the MicroCode package. While you do have to read the documents, the autorouter is about as good as any I've seen in the under-$10k category. That makes a big difference to me, since I work at the "front end" of a project, taking the notion form concept to prototype. I don't like to hunt extensively through libraries as I have to do with the EAGLE v3.55 package, but it's free, after all. and little boards of about 3-1/8" x nearly 4" work fine much of the time for my little one-of's. My normal approach is to enter a particular schematic, the same one for every software package I evaluate, and if that works OK, I try to route it. In the case of CircuitMaker, the first 5 devices were not available, so I gave up. That's over half the parts. When I checked with the Tech SUpport guys, they told me the libraries I had been sent were complete and no revisions or additions were planned at that time. The version-3 OrCAD did, indeed have a timing simulator. It's called OrCAD VST, having to do with verification and simlation. There's also a PLD and a PCB package. The schematic capture part is SDT. It also provides an on-line link to PSpice, v3.xx and beyond, from within the schematic capture package. If I were buying a low-end schematic and PCB software suite, I'd certainly look at EAGLE before I look at MircoCode stuff again, but that's as much because of the cost difference as it is due to the library shortfall. Needless to say, these are my opinions and inclinations. YMMV Dick -----Original Message----- From: Bruce Lane <kyrrin(a)bluefeathertech.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Wednesday, February 09, 2000 12:41 AM Subject: Re: Schematic capture/PCB design software >At 23:36 08-02-2000 -0700, you wrote: > >>I've got a sample package of CIrcuitMaker and TraxMaker and found it >>wanting, particularly in simulation models and device symbols. > > It would be. I don't believe Micro Code includes full libraries with the >sample versions. > >>would use the same package and symbol. They had nearly no AC or ACT parts >>represented, nor did they have BCT or F library components. Since you're >>paying for a simulator, there ought to be correct models for 7400, 74L00, >>74H00, 74C00, 74S00, 74LS00, 74AC00, 74ACT00, 74AHCT00, 74ACT00, 74AHCTLS00, > > A basic simulator at the digital level only looks at on/off states. That's >really all it has to do. Since all the parts you've listed above perform >EXACTLY the same function, and have the same symbol, I don't see why the >library has to include every possible variation on one part. > > FWIW, the current version of CircuitMaker Pro includes the following for >2-input NAND gates: > > 4011, 4093, 74F00, 74F132, 74F37, 74LS00, 74LS132, and 74LS37. > > While I agree that CM does need some help with their library, notably in >the more exotic components such as tunnel diodes, I have found it adequate >for my needs. The version of OrCAD you refer to only does schematic >capture, if I recall correctly, and has no simulation capabilities. > >>and so on. There ought also to be plenty of models for CMOS parts starting >>with 40xx, 44xx, 45xx, and a goodly number of 7300 and 7600 series parts. >>OrCAD had all that back in the mid-80's. They no longer offer that much >>coverage, owning to the increased knowledge of the user community, which >>would merely point out all their errors. > > I'm not sure I understand that last statement. If the omission of >components is itself an error, why would the "user community" not point it >out and ask for better coverage? > > Also, have you considered that there may be another reason? Specifically, >that the advancing state of technology where ICs are concerned has made >such wide varieties of parts unnecessary to accomplish a given task? > > To be perfectly honest, I've never heard of the 7300 or 7600 series parts. >I do know of TI's 75xxx series, which were line drivers/receivers, but I'm >curious about the ones you mention. > > Anyway, I feel that what CM lacks in library coverage is made up for in >other features. Also, there is nothing keeping you from adding to the >library. One can create their own SPICE models, though this is not >generally a trivial task, and I know there's at least one software package >available that lets you input specs from a databook and have it output a >SPICE model. > >>Have you found otherwise? > > As I've said: I've found that it serves my needs. I feel that it was a >good investment for the price I paid. Do I feel that most EDA software is >overpriced? Yes. Would I recommend CM and TM for any application? No. There >are better packages, but most are well beyond the hobbyist price range. > > Is there a need for an EDA package with better 'legacy' parts support? I >think so. I will continue to bug Micro Code about improving CM and TM along >those lines. In fact, we're probably due for an update this year. > > The bottom line is that a question was asked of the list members, and I >gave my opinion in response. The 'Free' packages simply do not suit my >needs. If they suit the needs of others, great! I was merely offering one >option out of many. > > >-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >Bruce Lane, Owner and head honcho, Blue Feather Technologies >http://www.bluefeathertech.com // E-mail: kyrrin(a)bluefeathertech.com >Amateur Radio: WD6EOS since Dec. '77 >"Our science can only describe an object, event, or living thing in our >own human terms. It cannot, in any way, define any of them..."

24 years, 4 months

Poor contact repair (was: Re: The pure *hell* of restoring a PDP-8/S desktop.

by allisonp＠world.std.com

<I'll have to try that. I guess, everyone has their own way of fixing bad <solder contacts. I've used the method I described over the past 16 years o <dozens of old mini computers... never had one come back because of problem <caused from the chemicals I use...< < <john Warning... Silicone grease is persistant stuff and one on what ever it's very hard to remove. So a board that requires soldering need that done FIRST then wipe the fingers with a thin film. If you get Silicone grease on something you dont want it on a it takes a lot of P11 (tetraflurocloroethane) solvent to get it off and trying to cook it off with the iron will not win due to very high temperature resistance of the stuff. Stuff like ethanol and Isopropanol (alchohols) will not touch it. Most quality contact cleaners that have a lubricant have some silicone in them. Allison

24 years, 4 months

How far can you reach in a dumpster?

by CLASSICCMP＠trailing-edge.com

> You must be a lot taller than I am. I jump up on the side and lean right >in. My favorite technique is to back my car up to the dumpster, pop the trunk open, climb on my bumper then into the dumpster, and start sorting and tossing the good stuff into the trunk. A good number of the PDP-11 freeware tapes in the archives were rescued that way :-). Tim.

24 years, 4 months

How far can you reach in a dumpster?

by jolminkh＠nsw.bigpond.net.au

-----Original Message----- From: Mike Ford <mikeford(a)socal.rr.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Wednesday, 9 February 2000 22:23 Subject: How far can you reach in a dumpster? My answer: Until it's too high to climb out again ! Ever since I found a PDP/8L in one a few weeks ago anyway.

24 years, 4 months

The pure *hell* of restoring a PDP-8/S desktop.

by dylanb＠sympatico.ca

Two weeks ago I *had* restored it.... and about every half hour it would break down with a different problem. I am posting this message in the hope that if anyone else ever has to restore such a nasty transistor mini then they can use this as a reference for *everything* that can go wrong with a minicomputer (excluding the power supply). First, the best methods I have found to eliminate the main problems in the most stubborn transistor minicomputers: 1) Bad contacts on backplane - Spray it with "Engine Gunk" (seriously, an automotive engine degreaser/cleaner), then stick a plain extender board with cloth wrapped around contacts and insert/remove a couple of times. Then use contact cleaner. 2) Weak Transistors - Lower the power supply voltage enough that poor transistors start to fail. 3) Thermal Transistor Breakdowns - (these are the Fairchild transistors that *always* fail due to the epoxy inside expanding and breaking contact). I recommend leaving the minicomputer on for 5 hours and let the poor transistors completely fail. Nothing worse than an intermittent one. BTW, I had 18 Flip Chips filled with this problem :-( (thanks for the info Allison!) 4) Intermittent Flip Chips - These occur in areas where the mini is running hot (ie: The MB register) and cause poor solder contacts which *might* be visible. I recommend pulling these altogether and replacing them. 100s of ticking timebombs. Get rid of all of them before you go insane. Use a digital thermometer and check for areas in excess of 115 degrees F (35 C). In the last 3 transistor minicomputers I have restored over the past 5 months I have found you will get a lot more intermittents if the mini was used *a lot* (ie: 12 years) and was stored in an area that varied greatly in temperature. 5) Expect your prints not to contain a complete schematic of the mini computer - I have found many changes to the straight-8, PDP-8/S that were not listed in FCOs but instead new prints were issued. (1960's) COMMON PDP-8/S Problems I have found: Since the speed at which data is switched through the PDP-8/S is *much* faster than the Straight-8 expect problems and replace/resolder the major registers and *ALL* pulse amplifiers. Most pulse amplifiers are switching at the maximum speed for such a Flip Chip (R602,603) so the slightest addition of resistance caused by a poor solder contact will cause endless problems. This PDP-8/S had the following problems (beyond the ones I mentioned before) Saul Dinman decided to add a *new* interrupt called "LPC", Low Power Condition. It will look like a negibus device interrupting the CPU but in fact is a few gates wired to the power monitor board. Of course, it only affects *PARTS* :-( of the CPU like... Parity! ,ION, and other nasty *bugs*. As the original 8/S did not have this installed it was not included in original prints :-(. I now found a third set with these mods... after spending a couple of hours pulling my hair out. After polling for interrupts and a memory parity error it is safe to conclude it is a low poer condition. Thanks Saul! Of course, everything else *only* failed when the CPU was running a program.. It's OLD instruction set was: ========================================= ION when an external device draws *just* enough power when being accessed to cause an LPC rather than an IO Interrupt :-(. Clear Accumulator Sometimes - (external device control) when warm and only when running a program and oscilloscope is not connected. Move AC->MB , 99 out of 100 times asked to. Stall CPU Clock 1mS - no longer or it might be seen without scope. and my favorite... If Zero, Branch Sometimes - BUT branch always in SI mode. ========================================================================= The PDP-8/S has now been running for over 6 hours and every major "bit" junction has been checked for a poor signal - all Fairchild's removed and buried. The desktop 8/S is a micro-sauna which means I will probably install fast boxer fans in place of the two eggbeaters currently installed in the back. My rackmount 8/s has 4 fans along the sides of the boards + 2 blowers, one above and one below. I am installing a 20ma->RS232 converter and will get this mini connected to Telnet with FOCAL loaded as quickly as I can. This mini needs a good month of continuous running to make sure it is finally... happy. PAPER TAPE: If anyone here is using a PC0 with a PC01 controller (Straight-8, or 8/S) I found internal mods used at DEC to increase the read speed from 300CPS to 650CPS... error free! 8/S *really* loads FOCAL fast now! I hope when I get a KA10 it isn't filled with the nasty problems this one had. john PDP-8 and other rare mini computers http://www.pdp8.com

24 years, 4 months

Schematic capture/PCB design software

by edick＠idcomm.com

Please see comments below. Dick -----Original Message----- From: Bruce Lane <kyrrin(a)bluefeathertech.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Tuesday, February 08, 2000 8:02 PM Subject: Re: Schematic capture/PCB design software >At 17:11 08-02-2000 -0000, you wrote: > > <snip> > >>Anyway, what came of that discussion and what were the recommendations for a >>good free package? > > <snip again> > > Unfortunately (for my needs at least) most of the "free" packages have too >many limitations to be useful. I had an old DOS version of OrCAD/SDT once, >and it did serve me well for some years. Thanks to having it, I was able to >do a "competitive upgrade" to Micro Code Engineering's CircuitMaker Pro and >TraxMaker Pro (about USD $700 or so for the pair). > > So far, it has proven to be a good investment. The digital simulation >functions saw me through some tough problems in one of my classes, and >produced output that had both my instructors raising their eyebrows. > > I'll be happy to answer any questions if you want to know more. > I've got a sample package of CIrcuitMaker and TraxMaker and found it wanting, particularly in simulation models and device symbols. When I got OrCAD in the mid-'80's they covered over 90% of the TTL and CMOS devices available. By comparison, I'd say I found these two to be lacking about 90%. It's really not a problem with their libraries, but with how they're managed. They build a symbol for 7400, say, but there's no guarantee there's a corresponding symbol for the 74HC00 or 74S37, which would use the same package and symbol. They had nearly no AC or ACT parts represented, nor did they have BCT or F library components. Since you're paying for a simulator, there ought to be correct models for 7400, 74L00, 74H00, 74C00, 74S00, 74LS00, 74AC00, 74ACT00, 74AHCT00, 74ACT00, 74AHCTLS00, and so on. There ought also to be plenty of models for CMOS parts starting with 40xx, 44xx, 45xx, and a goodly number of 7300 and 7600 series parts. OrCAD had all that back in the mid-80's. They no longer offer that much coverage, owning to the increased knowledge of the user community, which would merely point out all their errors. Have you found otherwise? > >-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >Bruce Lane, Owner and head honcho, Blue Feather Technologies >http://www.bluefeathertech.com // E-mail: kyrrin(a)bluefeathertech.com >Amateur Radio: WD6EOS since Dec. '77 >"Our science can only describe an object, event, or living thing in our >own human terms. It cannot, in any way, define any of them..."

24 years, 4 months

New list - "PDP-archives"

by CLASSICCMP＠trailing-edge.com

Hi Folks, You might remember me, I'm the guy who maintains the PDP-11 software archives at http://metalab.unc.edu/pub/academic/computer-science/history/pdp-11/ and the PDP-10 software archives at http://pdp-10.trailing-edge.com/ In order to maximize the utility of these archives to users, as well as to encourage discussion of the archives (as in, "Hey, I just found a really neat Battleship game for my PDP-10"), I've formed a new mailing list: "PDP-archives". It will be for the discussion not only of the above archives, but also for discussion of other archives and general topics about how to best archive and distribute old PDP-8, PDP-10, and PDP-11 software. (Other PDP-nn software is welcome too, of course!) To subscribe, send an E-mail request consisting of the line subscribe PDP-archives to PDP-archives-request(a)mudd.trailing-edge.com Alternatively, visit http://mudd.trailing-edge.com/mailman/listinfo/PDP-archives and sign up using the web interface. See you on the list! -- 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

24 years, 4 months

← Newer
1
...
38
39
40
41
42
43
44
...
59
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb February 2000