test-drb February 2000

test-drb@ccmp.vtda.org

162 participants
585 discussions

Electrolytic capacitors and other picture postcards.

by allisonp＠world.std.com

<started to get flakey and now won't come up at all. Is my <understanding of ecaps correct? That is, as long as the <capacitance is correct, the voltage is greater or equal to <the required load and it is installed "right way around" <it should be OK? There is so much logic on this board, a They should not exceed 3x the wrking voltage plus any spikes that may occur. Electrolytic caps run at .25 or less the rated working voltage will not form and the actual capacitance will diminish. The later does take a bit of time usually. Likely the shorted caps are of the "tantalytic" tantalum electrolytic variety and they are know for that behavour. In any case the newly installed caps should have the following: -Short leads. -Working voltage of not more than 15-20V for a 5V rail, 50V for a 12-16V rail. -of course the replacement should be known good. The flakeyness is likely due to some other factor that may be due to the power cycling. I'd check the PS for a tired cap (a big one) or maybe a fried rectifier. It's conceiveable the output voltage is at the lower limit and causing flakies. <lot of it 8Txx, I hope I haven't blown a chip. It would <take me a month to find it and who knows if I could get a <replacement. Most of them are common enough and have TTL 74xx replacements that should work just fine. Allison

24 years, 10 months

JVC GD-H4220US multi-sync monitor help needed

by pete＠dunnington.u-net.com

On Feb 7, 13:59, Ethan Dicks wrote: > Can anyone point me to a chart that has the older 9-pin RGB standard? I can > verify my adapter, then. Also, I'm not sure what kind of sync a CG6 generates. I'd have thought the Amiga adapter would work, if anything would, providing it's for an analogue monitor. Here's the pinout from my Acorn Archimedes, which uses a pretty standard multisync pinout: Type: DE9 Pin Function ---------------- 1 red 2 green 3 blue 4 composite sync 5 optional vertical sync 6 red ground 7 green ground 8 blue ground 9 sync ground and for comparison, CGA (which is TTL, not analogue): Type: DE9 Pin Function ---------------- 1 GND 2 Reserved (no connection) 3 red 4 green 5 blue 6 intensity 7 Reserved (no connection) 8 horizontal sync 9 vertical sync -- Pete Peter Turnbull Dept. of Computer Science University of York

24 years, 10 months

[CC] Wanted: Macintosh speech program called "Smooth Talker"

by mtapley＠swri.edu

David Vohs wrote: >I am looking for a driver for aforementioned Macintosh for an Apple Color >Stylewriter 2400. I don't want that printer to be reduced to dust magnet >status! http://asu.info.apple.com/swupdates.nsf/artnum/n10265 Don't know what system software it requires, but considering it's dated 1/97 it should be OK with 7.0.1 or 7.1, both of which run fine on my Mac Plus. - Mark

24 years, 10 months

How to switch to digest mode . . .

by Historical＠aol.com

Hello everyone, sorry to ask through the list, but could someone please direct me in this? I used to be in digest mode. Thanks very much. Best, David Greelish Classic Computing Press www.classiccomputing.com

24 years, 10 months

JVC GD-H4220US multi-sync monitor help needed

by ethan_dicks＠yahoo.com

I was just gifted with a GD-H4220US monitor that isn't behaving as expected. My best Web research indicates that it is a 19" analog/digital RGB monitor (dual 9-pin connectors and a mode switch) with scan rates of 15-37Khz and 45-87 Hz. I have attached this device to an Amiga 3000, my 486 LRP box and a SPARC2 w/single-width CG6 (via the standard 1395 13W3 adapter). In no case does this monitor give me a locked, stable display. The CG6 does the best, but the top dozen lines do not align, giving a "torn" appearance. The Amiga 3000 (15.75Khz and 31Khz, both) produce at best, two copies of the video, one on the top half of the screen, one on the bottom half. The externally accessible controls are a bank of 4 pots with height, v alignment, width and h alignment icons, labelled A through D; an overscan enable switch; a "cancel preset" switch and the usual bright and contrast controls on the front. I am using two different adapters to convert the monitor's 9-pin RGB to the more common 15-pin high-density connector used today for VGA. One adapter is a short cable, source unknown, the other adapter came with my Amiga 3000. Both adapters produce the same results. I have color, I have video data. I appear to be lacking in the sync department. The only other specs I found on the H4220US is that is is H-V, +ve sync. What I'm not sure about is how common positive sync is these days (it may be the standard for all I know; I've seen negative sync stuff in the past) and whether or not my adapters are properly propogating the sync signals. There is, of course, the possibility that the monitor is defective, but I suspect wiring, first. Can anyone point me to a chart that has the older 9-pin RGB standard? I can verify my adapter, then. Also, I'm not sure what kind of sync a CG6 generates. Can someone shed some light there, too? It's a really awesome monitor, especially for the price. Even with the plastic cover off, it generates no audible noise, unlike every other monitor in the room. One drawback: 2.3A listed draw (4A fuse). That's a lotta watts to keep powered on. I have the covers off at the moment and can find no obvious place to tweak the sync circuit. The manufacturing date is 1989 and it does not appear to be microprocessor controlled. Nothing appears obviously smoked or disconnected. I do not have any documentation to go with this display. Thanks in advance, -ethan ===== Infinet has been sold. The domain is going away in February. Please send all replies to erd(a)iname.com __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com

24 years, 10 months

JVC GD-H4220US multi-sync monitor help needed

by ethan_dicks＠yahoo.com

--- Pete Turnbull <pete(a)dunnington.u-net.com> wrote: > On Feb 7, 13:59, Ethan Dicks wrote: > > > Can anyone point me to a chart that has the older 9-pin RGB standard? > Here's the pinout from my Acorn Archimedes, > which uses a pretty standard multisync pinout: > > Type: DE9 > > Pin Function > ---------------- > 1 red > 2 green > 3 blue > 4 composite sync > 5 optional vertical sync > 6 red ground > 7 green ground > 8 blue ground > 9 sync ground This is _very_ close to what I eventually found at pinouts.com... NEC 9-pin Multisync: http://www.pin-outs.com/datasheet_58.htm IBM 15-pin VGA: http://www.pin-outs.com/datasheet_15c.html The difference is that on the NEC 9-pin, 4 and 5 are H. Sync and V. Sync. >From this information, my adapters are a) identical and b) correct. They do connect pin 4 on the 9-pin side to pin 13 and pin 5 to pin 14, as one might expect. The analog wires and associated grounds are as expected. I guess I'm down to either inverted sync or a defective monitor. Thanks for the nudge in the right direction. -ethan ===== Infinet has been sold. The domain is going away in February. Please send all replies to erd(a)iname.com __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com

24 years, 10 months

JVC GD-H4220US multi-sync monitor help needed

by ethan_dicks＠yahoo.com

--- Pete Turnbull <pete(a)dunnington.u-net.com> wrote: > On Feb 7, 13:59, Ethan Dicks wrote: > > > Can anyone point me to a chart that has the older 9-pin RGB standard? > > I'd have thought the Amiga adapter would work, if anything would, providing > it's for an analogue monitor. It is. I've used it on an ancient IBM "Professional Graphics Adapter" monitor - same case as the original IBM Mono monitor from the 5-slot PC days, but 31.5Khz, analog, and color. I would have thought it would work, too, but something's odd about it. Perhaps it's sync polarity. > Here's the pinout from my Acorn Archimedes, > which uses a pretty standard multisync pinout: Thanks. I'll check my adapter. -ethan ===== Infinet has been sold. The domain is going away in February. Please send all replies to erd(a)iname.com __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com

24 years, 10 months

FS: Mainframe and minicomputer manuals and control panels, and a complete storage technology collection.

by kstumpf＠unusual.on.ca

If you need or would like to buy these types of items, please send to me, in a private inquiry, a description of what you are looking for. I'll look for those item(s) and send a reply. Here is a slightly more detailed list: Mainframe manuals - all and any vendors - mostly theory of operation, functional specifications-type of manuals DEC maintenance manuals - just a few DEC handbooks - just a few Brochures - mainframe and minicomputers all in mint condition Pocket reference cards - mostly IBM 360 Tabulator manuals - Friden and IBM Tabulator plug board (just a small one) Control panels - mainframe and minicomputers Control consoles - IBM 705 and UNIVAC 1108 Punch cards - boxes (2 000 cards per box) of'em Collection of storage mediums - paper and magnetic including sonic delay line from IBM 2260 controller and core (would like to sell the collection complete, but will do what I must do) Auerbach library of Computer Technology Reports from 1962 to 1989 - hundreds of manuals and reports Books - mostly introduction to data processing or computers-type books Hope you find something you've been looking for. Yours in good faith Kevin Stumpf - The Nostalgic Technophile www.unusual.on.ca - 519.744.2900 EST/EDT (GMT - 5) Author & Publisher of The Guide to Collecting Computers and Computer Collectibles: History, Practice, and Technique

24 years, 10 months

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

by dylanb＠sympatico.ca

-----Original Message----- From: Dwight Elvey <elvey(a)hal.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Monday, February 07, 2000 10:29 PM Subject: Re[2]: The pure *hell* of restoring a PDP-8/S desktop. >Edward Taussig <taussig(a)arpanet.com> wrote: >> Hi. Stabilant 22 was touted highly by Jerry Pournelle in Byte magazine >> as a contact enhancer, it might help after a good de-gunking. >> http://www.stabilant.com/ >> >> http://www.byte.com/art/9705/sec13/art1.htm >> "Stabilant 22, the miracle all-purpose contact enhancer. It not only makes >> for better electrical contacts -- a major use of Stabilant 22 is to get all >> the electrical noise out of hi-fi systems -- but also lubricates connector >> insertions. If you don't use Stabilant 22, I bet you wish you did." >> > >Hi > Why use someone's resold product when you can just >buy some silicone grease like DC4 and it works fine. >DC4 will last longer because it contain a binder. >As for degreasing, I would suspect that something like >brake clean would be better on electronics. Gunk engine >cleaner has corrosives and is hygroscopic. I don't think >I want that in my machine. It would surely cause >long term problems. I have been using engine gunk in minis for many years and have never had any come back. I am dealing with dirt/crud so thick that you couldn't get it off with just scrubbing. After the engine gunk I vacuum out the backplane, then use contact cleaner. I have never had a problem or a bad contact after that. This should only be used in minis where regulart contact cleaner fails. I have rarely had to use it because most minis come out of labs and are very clean. This mini has been sitting in a warehouse, unprotected for at least 25 years. The dirt was so thick on the negibus cables that I had to soak them in a tub for 4 hours and scrap the dirt off in layers. Looks like a millions $$ now but was disgusting to even handle before. Amazing how much dust and garbage something can accumulate over 20+ years. (it's been running 10 hours now without problems :-) ) john PDP-8 and other rare mini computers http://www.pdp8.com >IMHO >Dwight > >

24 years, 10 months

Commodore PET Anatomy Pictures

by foxnhare＠jps.net

Just Added to my ever-growing Commodore Pages: Anatomy of the PET http://www.jps.net/foxnhare/pet/anatomy.html This is a collection of photos I took a bunch of months back displaying my PETs (and Educator 64) their case designs, keyboards, circuit boards, etc. It gives a good overview of the American Line of the various Commodore PET/CBMs. Such interesting things to see also in the Anatomy are: * A picture of the 'drilled ram area' that commodore had done to keep schools from expanding their PETs bought at a discount. * A pictures of the Early SuperPET board set and a close up of the two-switch version. * A picture of the three earliest designs of the C2N datasette * In the pictures you will see an original PET RAM Expansion, Graphics Expansion and a RAM/ROM Emulator. -- 01000011 01001111 01001101 01001101 01001111 01000100 01001111 01010010 01000101 Larry Anderson - Sysop of Silicon Realms BBS (209) 754-1363 300-14.4 bps Commodore 8-bit page at: http://www.jps.net/foxnhare/commodore.html 01000011 01001111 01001101 01010000 01010101 01010100 01000101 01010010 01010011

24 years, 10 months

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test-drb February 2000