test-drb December 2001

test-drb@ccmp.vtda.org

243 participants
1096 discussions

[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

From: Mark Crispin <mrc(a)CAC.Washington.EDU> >I am appalled that anyone would seriously consider putting any electronic >equipment, much less antiques, in a dishwasher. You never seen how they were made then. >It may be alright to (gently!) vaccuum away dust and deteriorated foam >rubber, although a feather duster may be more appropriate. I would not Believe it or not vacuuming can create damaging ESD for sensitive boards like core drivers and even TTL! >risk anything else, and certainly not insert anything (including water or >alcohol) under the plexiglass shield protecting the core. Correct there. The core plane is fragile. >A damp cloth with perhaps a bit of soap to the exterior surfaces of the >case is probably all you really need, but be sure not to let any liquid >seep into the inerior. A lot of the PDP-8s have lived in industrial enviornments and offices where clean air is unheard of. Many really are filthy. Allison

23 years

how to clean a PDP8/A, dishwasher?

by ajp166＠bellatlantic.net

From: Gunther Schadow <gunther(a)aurora.regenstrief.org> >I have that itching to start up my new PDP8/A even without >disks attached. Have a programmers console, so that's enough >to enter a few programs. It's intriguing to see a machine Congrats! >But first I need to give this thing a good cleaning. A friend >has assured me that there's nothing better than the dishwasher, >with the exception of big capacitors and, what about magnetic >core memory? So, how should I clean the RAM cards? How the >DC power supply units? The PS do by hand and CORE planes never goes in the dishwasher. The core IO boards can be dishwashed. >If I put the other stuff in the dishwasher, I know there should >be no detergent and no heat dry. But what about the rinsing >aid, do I have to pump this out of the reservoir? No problem. I use minimal detergent as most of the dreg on the boards is water soluable. >I heard of another method using hand-washing first, then drying >and finally a bath in Isopropanol. Is that what I should do >with the core memory cards? Core planes are very fragile and usually covered enough to prevent much muck inside. the driver boards usually get nasty dirty. >Finally, finally, I noticed that the cards are all slightly >bent from being kept in a horizontal position. They are sagging >a little, like a hammock. Would that be a cause of concern >in the long run? Should I mount the chassis in an upright >position in the future? Not an issue, dont try to straighten. >PS: I am probably going to make one "portable" PDP-8, where >the console is mounted on the chassis and the rest of the >opening covered plus a handle on the top. That would be neat >for bringing into the classroom to teach fundamentals of >computer programming, wouldn't it? yes it would PDP-8 is still a good minimalist model to work from. Allison

23 years

[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 15, 9:27, Ben Franchuk wrote: > I also would consider the qaulity of the water. I would wash in > distilled > water. The last thing you want is clorine or other acids and junk from > the > water slower eating your PCB. For the time it takes to wash a PCB, nothing dissolved in normal water is going to matter. Make sure it's free of paticulate matter that might get stuck somwhere, don't use the raw undiluted waste from someone else's chemical process, but there's no need to go over the top. The chlorine added to tap water, for example, will do no harm. -- Pete Peter Turnbull Network Manager University of York

23 years

Flashing Light Indicators un Simple Front Panels

by mcguire＠neurotica.com

On December 15, Douglas Quebbeman wrote: > No, I'm afraid you may have hit it on the head, and it's been the > direction I've been leaning, that the microcode ROMs may have > fried, but that just blows my mind. Tonight, I'll set up the No, Doug...the microcode ROMs being fried should blow the PR1ME's mind, not yours. ;) (Sorry, I couldn't resist!) > PC that's got my ROM burner/reader, and read each one (if the > ROMs aren't too large a size for my Needham unit). I'm assuming > I'll see all 00s or all FFs (or maybe something like FEs) if > they're blown; been a long time since I've looked at popped > ROMs... What kind of ROMs does it use? Another possibility might be to find someone with the same model of PR1ME (how rare are they?) and checksum the ROMs & compare them...most PROM burners will generate checksums, but now that I think of it, PROM burner manufacturers have yet to standardize on a checksumming algorithm so it'd probably be useless unless they're summed with the same make/model of burner. :-( -Dave -- Dave McGuire St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf

23 years

Flashing Light Indicators un Simple Front Panels

by dhquebbeman＠theestopinalgroup.com

> On Dec 14, 16:16, Douglas Quebbeman wrote: > > > In particular, do any of you have familiarity with > > systems that flash the on or power light as an > > indicattor, sopecifiecally, of a power supply > > problem? > > The only thing I can think of that's *designed* to do something like that > is an SGI Indy; if you power one up and it can't even run the the code in > the PROM, it flashes the power light (which is a two-colour LED). The > usual cause id that there's no (recognisable) RAM at all in it. Probably > not relevant to a PR1ME. No, I'm afraid you may have hit it on the head, and it's been the direction I've been leaning, that the microcode ROMs may have fried, but that just blows my mind. Tonight, I'll set up the PC that's got my ROM burner/reader, and read each one (if the ROMs aren't too large a size for my Needham unit). I'm assuming I'll see all 00s or all FFs (or maybe something like FEs) if they're blown; been a long time since I've looked at popped ROMs... About the only other possibility is that the backplane got cooked, but it looks fine... -dq

23 years

[PDP8-Lovers] how to clean a PDP8/A, dishwasher?

by msell＠ontimesupport.com

Guys, This argument always comes up every few months on the video game collecting newsgroups that I'm a member of. Here we go.... How do you think the boards were cleaned by the manufacturer? Boardwashers!!!!! (big versions of dishwashers - usually with conveyors for constant operation) I've been employed by two different electronic test equipment manufacturers, and have consulted a bunch more regarding quality control and calibration of electronic test equipment. EVERY SINGLE ONE OF THEM USES WATER TO CLEAN THE BOARDS. No shit. Depending on the type of equipment that is being produced, some may use distilled water, others filtered water, some use "deionized" water. But it's still water. Hot water. I clean all of my computers, upright video games, and all of the boards >from my two 11/780's and one PDP-11/34A in the dishwasher. No damage yet, after several YEARS of doing this. I've put high-voltage power supplies, low voltage power supplies, floppy disk drives, CPU boards and everything else in the wash. What doesn't fit in the dishwasher gets blasted with 409 and hot water in the tub. Here's the secrets to doing this right: 1) Do not use any detergents. NONE. 2) Turn off the plate warming and drying cycles. The heating elements in the washer can distort or damage plastics. 3) Remove soon after cycle is complete. Do not let items sit overnight. Shake off water. 4) Stand up or hang to dry. 5) Let items dry inside the house for several days. I usually don't touch washed items for at least 3-4 days. 6) Don't plug the item in to power of any form until step #5 has completed. For delicate items, I use water from the sink at a low flow rate, and spray a mixture of 409 and water onto the item and allow it to soak for a few minutes before rinsing. I may use a soft paintbrush to clean stubborn dirt if necessary. Rinse and repeat. I know that a good percentage of you are skeptical. Every one of my games in my arcade collection had at least the CPU boardset in the dishwasher. Several others had every single board through the wash. All of them work, and did so before going into the dishwasher and immediately after drying. Others had the monitors powerwashed. I took an entire 11/780 out into my driveway and I powerwashed the chassis AND backplane! Don't take my word for it; take a board that you know is operational, of little value to you, test it out, and run it through the dishwasher using the steps outlined above. After a few days of drying, test it out. It'll work. And - I severely doubt that you get it any cleaner using any other method. Of course, don't wash the boards with your regular load of plates and pots..... : ) - Matt At 10:25 PM 12/14/2001 -0800, you wrote: >On Fri, 14 Dec 2001, Gunther Schadow wrote: > > But first I need to give this thing a good cleaning. > >Why? > > > A friend > > has assured me that there's nothing better than the dishwasher, > > with the exception of big capacitors and, what about magnetic > > core memory? > >I am appalled that anyone would seriously consider putting any electronic >equipment, much less antiques, in a dishwasher. > >It may be alright to (gently!) vaccuum away dust and deteriorated foam >rubber, although a feather duster may be more appropriate. I would not >risk anything else, and certainly not insert anything (including water or >alcohol) under the plexiglass shield protecting the core. > >A damp cloth with perhaps a bit of soap to the exterior surfaces of the >case is probably all you really need, but be sure not to let any liquid >seep into the inerior. > >-- Mark -- > >http://staff.washington.edu/mrc >Science does not emerge from voting, party politics, or public debate. Matthew Sell Programmer On Time Support, Inc. www.ontimesupport.com (281) 296-6066 Join the Metrology Software discussion group METLIST! http://www.ontimesupport.com/cgi-bin/mojo/mojo.cgi "One World, One Web, One Program" - Microsoft Promotional Ad "Ein Volk, Ein Reich, Ein Fuhrer" - Adolf Hitler Many thanks for this tagline to a fellow RGVAC'er...

23 years

Color Coding, A/C (Mains) Leads, USA ONLY, Redux

by dhquebbeman＠theestopinalgroup.com

> Two parallel blades is 120V 15A. One perpendicular to the other is > (usually!) 120V 20A, but it could be a 250V plug, too. The 120V 20A plug > can be adjusted to fit a 15A recep by the judicious(sp?) application of a > pair of pliers... No, I've never done such a dangerous thing! -_^ Just > remember, too close to the body of the plug and it'll shear off, too far out > and it won't insert fully into the plug. Sorry I wasn't clear- plug matches the outlet it goes into, no need to "re-engineer"... -dq

23 years

Hardest to Find Classic Computers

by dhquebbeman＠theestopinalgroup.com

> The Lilith & the Tektronix Magnolia. These I regret not > hanging on to. I have never seen another. I still have > a Lilith mouse. Did the Magnolia really Smalltalk-80 in reverse-video mode? The only ones I've seen were in photos, and one showed white text on black background in Smalltalk... -dq

23 years

how to clean a PDP8/A, dishwasher?

by pete＠dunnington.u-net.com

On Dec 14, 23:47, Gunther Schadow wrote: > But first I need to give this thing a good cleaning. A friend > has assured me that there's nothing better than the dishwasher, > with the exception of big capacitors and, what about magnetic > core memory? So, how should I clean the RAM cards? How the > DC power supply units? NOT the core! If you need to clean the core, my suggestion would be to immerse it in a washing-up basin with tepid water and a little soap or washing-up detergent, and *gently* swish it about a little. Then rinse twice, let it drain, and dry off gently. Don't use compressed air or solvents. > If I put the other stuff in the dishwasher, I know there should > be no detergent and no heat dry. But what about the rinsing > aid, do I have to pump this out of the reservoir? I don't think the detergent will do any harm, providing it's not too caustic, but avoid excessively hot water and high-temperature drying. Before you use the dishwasher, check for switches etc that might not take kindly to being immersed in soapy water, and either carefully remove them (taking careful note of where they go) and relays (don't wash relays). Also check for any labels that will be damaged or which might come off and end up where you don't want them. The rinse aid won't do any harm at all, in fact it wil help the water drain off (it's just a wetting agent). > I heard of another method using hand-washing first, then drying > and finally a bath in Isopropanol. Is that what I should do > with the core memory cards? Yes, see above, but omit the IPA. When I cleaned my PDP-8/E recently, I put all the boards except the core in the dishwasher, along with the front panel circuit board (I removed the LEDs first, since they were in bi-pin sockets), over-the-top connectors, and the two backplanes. I ran it on the usual cycle, with detergent and rinse aid. When I took the boards out, I blew off the remaining water (some tends to stay under ICs) with compressed air, and gave anything that might harbour water (DIP switches, panel switches) a good dose of iso-propyl alcohol, which I then drained/blew off. The IPA mixes with the remaining water and helps to remove it; the air removes the last traces of IPA. Finally I treated all the switches to a small dose of low-residue switch cleaner/lubricant. Similar treatment for the backplanes and connectors, except it's hard to get the last of the water/IPA out so I let them stand upright in front of a hair drier on a low heat setting for a couple of hours while I got on with other things. The PSU was too big for the dishwasher, and I wouldn't have wanted the transformer in there anyway. The 8/E has a linear supply with a big transformer; the 8/A has a switcher, I think. Anyway, I took off the side panel, removed the fans, relay, and fuse carriers (carefully noting how they were wired). I sprayed it with enzymatic cleaner (it was smelly) and detergent mixed with water in a spray bottle to dissolve the muck, left it to sit for a few minutes, and then rinsed it out with the garden hose (low pressure!) trying to avoid getting too much water into the transformer. Then I drained it out, and used most of a 500g aerosol of IPA to flush out the water, and compressed air to remove the residue, especially in the connectors. I let it stand in a warm dry room overnight before powering it up; I figured there might still be dampness in nooks and crannies in the transformer, and I didn't want to take chances. If you have small parts that need washed, then they can go in the cutlery basket in the dishwasher providing they're heavy enough not to jump out (metal brackets for example) or in a strong mesh bag in the dishwasher. For more delicate things you can tie them in a pillowcase and put them in the washing machine. I use the pillowcase/washing machine for keytops, cartridge cases, etc. Most of the foam in my 8/E was past redemption, so I stripped it off with a wallpaper stripping knife and replaced it with "high-density" upholstery foam about 3/8" thick -- not the really high density stuff that seems to be made of lumps of recylcled stuff, just the stuff used to pad seats. I cleaned off the old glue and stuck the new foam on with spray glue, after masking off the area to spray (like you would for spray paint). The foam under the backplanes was OK, so it went in the (clothes) washing machine on a hot wash. > Finally, finally, I noticed that the cards are all slightly > bent from being kept in a horizontal position. They are sagging > a little, like a hammock. Would that be a cause of concern > in the long run? Should I mount the chassis in an upright > position in the future? Not unless they're so badly warped that things might short between cards. Some of mine were warped when I got them, and don't seem to have suffered. > any other things I should know? Use a pen torch to look in the backplane slots for any rubbish the dishwasher might not remove (paperclips, cruddy foam, etc). Do make sure everything is dry before you power them up (or even reassemble them). Do make a note of where and how everything you remove goes back. I thought all the LEDs in my panel were the same way up; they weren't and it took me half an hour (without the circuit diagrams) to get them all the right way round. I find it helpful to put the screws from each section or panel or whatever into a separate ziplock bag or a dish; there are always some missing and it helps figure out what goes where, how many are needed, and what lengths they should be when you come to reassemble it all. Check the fans rotate freely; I always relubricate bronze bearing types with light machine oil. I have a few toggle-in programs I've collected or modified for first-time confidence testing, like the inchworm program and a couple of serial port testers (continuously write character to console; echo console, etc). -- Pete Peter Turnbull Network Manager University of York

23 years

Co-routines was Re: [PDP8-Lovers] if you hadn't already known this about the PDP-8

by mranalog＠attbi.com

"Sean 'Captain Napalm' Conner" <spc(a)conman.org> wrote: > So what, exactly is a co-routine? I've heard the term before, but I'm not > entirely sure what they are, or how they would work. > -spc (I may have used them in assembly, but not knew the proper term ... ) The only time I remember using a coroutine was a time when I had no interrupts to use. The Sega Genesis has a 68000 with main program memory, plus a sound system controlled by a Z80 with it's own sound memory. Sound memory is loaded with a sound driver written in Z80 assembly. Now the sound system has a free running timer but no interrupts, so most games had a sound driver that played FM sounds or a sound driver that played digitized sound. My job was to take an FM sound driver and make it play digitized sound at the same time. So I wrote a routine that quickly checked if a digitized sound was playing and if it was, then check if it was time to stuff the next value of the digitized sound. The hard part was then to pepper the existing sound driver with calls to this coroutine such that the existing sound driver would not be slowed down and that the digitized sound would be played at a constant rate. It worked great. Oh! "what, exactly is a co-routine?" A coroutine is a procedure that executes from the point it last suspended execution up to the next instruction that suspends its execution. That is, it preserves state between invocations. Regards, --Doug ========================================= Doug Coward @ home in Poulsbo, WA Analog Computer Online Museum and History Center http://www.best.com/~dcoward/analog =========================================

23 years

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test-drb December 2001