test-drb January 2005

test-drb@ccmp.vtda.org

254 participants
551 discussions

by dwight.elvey＠amd.com

Hi My understanding is that NiMH's have a higher internal resistance when mostly discharged and should be charged slowly until the internal resistance drops. They are also suppose to be less tolorent to over charging than NiCad's. In general, I'd expect one to get poor battery life using a NiCad charger on NiMH's. 0.1C is not a trickle. 0.02-0.01C is. 0.1C will cause quite a bit of heating in a fully charged cell. 0.1C is only recommended for normal rate of charging NiCad's, not as a trickle level. Dwight >From: shoppa_classiccmp(a)trailing-edge.com > >> I have noticed that NiMH prices have gone down >> about half over the last 5 years. > >In many cases they are cheaper than NiCads now. > >This raises a question for refurbishing older equipment: is it always >OK to just drop a set of NiMH's in place of same-size NiCad's? Most >of the "stupid" NiCad battery chargers were just 0.1C trickle chargers, >but the "smart" ones that looked for the voltage rise at the end of charge >of a NiCad may not see this with a NiMH pack. Anyone have any experience? > >Last time I had to put some new Sub-C cells in my Fluke scopemeter I had >to look rather hard to find true NiCads as opposed to MiMH's. > >Tim. >

21 years

Mac 128, was Re: Desktops then and now (book review)

by Innfogra＠aol.com

In a message dated 1/17/05 12:28:29 A.M. Pacific Standard Time, mike(a)ambientdesign.com writes: I have a very nice one, as-new, with original carry bag, printer, external floppy, manuals, etc, but didn't think it was overly rare. I'll be happy enough if I'm wrong... A 128K Mac set like that is a nice collectable, especially with the docs and disks. It could make epay live up to its name. Condition is all important as are the original SW and docs. I don't know of it's rarity. Many were upgraded to 512K so there are not that many in existence. Paxton Astoria, OR

21 years

Nickel Metal Hydrids

by dwight.elvey＠amd.com

Hi I would guess that your method is most likely the best. Keeping them at full charge tends to create those metal fingers inside that short them out. Discharging them as packs tends to reverse charge some of the cells causing out gassing and cell rupturing. I don't know if the NiMH I had was drained by load or just by sitting around. It is an old machine ( about 13 or 14 years old ). I would guess that these cells have a similar problem if fully discharged as a battery stack. The laptop had no normal signs of wear like a similar one that I had ( video is failing ). It may have only been used for a year or so and then just placed in storage. Most times when I come on NiCads that have zero volts, I find the cells to have an internal short. Either NiMH have something that keeps this from happening or I was real lucky. I do know that wet NiCads ( those with vents ) are usually shipped with a shorting bar. I would guess that if one individually drained the NiCad cells, they could be stored a long time. I'll let you guys know how things are after a couple more days. Hopefully the battery will remain useful. Dwight >From: "John Allain" <allain(a)panix.com> > >> Most NiCads batteries would not recover from such a level. > >How should NiCads be stored? >Sounds line 0v is a terrible idea. >I usually put them away at normal discharge, >about .8-1.0v and then charge a few hours before >next use. >All I really know is that: > o. 300 recharges is about all you can expect, and > o. topping off is no good > >My guess is that unused NiCads could reach 0v >after a year or two on the shelf. If you restore a >collectable and then shelve it for 10 years only >to find it's dead _again_ it won't be gratifying. > >It might not be worth sweating this detail, however. >I have noticed that NiMH prices have gone down >about half over the last 5 years. > >John A. >

21 years

DEC version of "101 Basic Computer Games"

by shoppa_classiccmp＠trailing-edge.com

> David Ahl's "101 Basic Computer Games" published by DEC > in 1973 (this one is from the 1974 2nd printing). Does it have a DEC Order Number on it? Is it EB-04873-76? Ahl's DECUS submissions of these games are online at http://pdp-11.trailing-edge.com/rsts11/rsts-11-013/index.html http://pdp-11.trailing-edge.com/rsts11/rsts-11-014/index.html Tim.

21 years

Slightly OT: world's smallest hard drive

by news＠computercollector.com

http://news.com.com/Disk+drives+to+stop+shrinking/2100-1004_3-5532612.html?… ===== Tell your friends about the Computer Collector Newsletter! -- It's free and we'll never send spam or share your email address -- Publishing every Monday(-ish), ask about writing for us -- Mainframes to videogames, hardware and software, we cover it all -- W: http://news.computercollector.com E: news(a)computercollector.com -- 646 readers and counting!

21 years

email was Mac something something

by dwight.elvey＠amd.com

>From: "Vintage Computer Festival" <vcf(a)siconic.com> > >On Thu, 13 Jan 2005, Paul Koning wrote: > >> >>>>> "William" == William Donzelli <aw288(a)osfn.org> writes: >> >> William> .... Some of the things were >> William> pretty cool - a 400 cps (!) paper tape punch, ... >> >> Wow. I've love to see one of those. The fastest I have seen was, I >> think, a 120 cps punch. Listening to one of those running at full >> speed is pretty impressive. >> >> Paper tape readers can go much faster (I've seen 2000 cps) but those >> are optical readers, so the job is far easier. > >I don't suppose anyone ever manufactured a laser-based paper tape punch? >Is that even feasible? > Hi Sure, it could be done. The only reason it hasn't been done was that the medium was obsolete by the time the LASERs were ready. I used to have fun with a 20W CO2 LASER. I could control it well enough to remove 6 or 7 layers of paper. Each time I'd cut a little deeper. It would make a pop sound and some of the paper would just be disappear :) Dwight

21 years

Linux and an old IBM PS/2 8570

by john_boffemmyer_iv＠boff-net.dhs.org

I recently got an old IBM PS/2 8570 (as mentioned to some earlier). Been thinking about putting Linux on it as the original owner put some company proprietary software on it for some unknown network monitoring via proprietary hardware (that has since been removed before I came into possession). The big thing is that it doesn't want to boot from SCSI. I have 4 cards and the adf disks for them. 1 is an IBM (supposedly Corvette) controller. 2 are Adaptec 1640's (different year manufacture and slightly different layout/revision). The final one is a Storage Dimensions 3211B (technically a compatible, yet rarer C/D). The other thing is that I've been told it has some sort of special boot partition on the 60MB ESDI drive. The SCSI drives I'm trying to use are all 1 and 2.2GB Seagates with an external Sun 611 enclosure (again, making the 10 year rule from what I've been told). If I can get the damned thing to take the SCSI drives and not the 60MB ESDI, that would be the ideal situation. If I have to use the 60MB ESDI as the boot drive, how could I get this to work as I've never tried Linux on an MCA before and everything I find out there seems not to pertain to my situation? The other cards in the machine are an IBM Long 16/4 (DB9 out) Token Ring card and I was thinking of using a Kingston 8000 Memory card (any info on this unique piece of hardware would be greatly appreciated as all I can find are the adf's for it). Anyone know what the max size and type memory was for that card and how it was implemented? Worst case scenario is that I simply don't use it, as the bigger goal is to get the damned thing working with Linux on SCSI and Token Ring. If people are hesitant on helping me, I have a bunch of spare MCA DB9 16/4 Token Ring cards (long and short), SCSI cards (as described above) and a couple XGA and XGA2 cards wthat I'm willing to offer for shipping in exchange for help. Hell, I've even willing to give up the odd Kingston memory card if it got me some help. Any takers? Please reply off-list, thanks. -John Boffemmyer IV john at boff dash net dot nospamdhs dot org (just drop the nospam) ---------------------------------------- Founder, Network Engineer, Tech Analyst and Web Designer Boff-Net Technologies http://boff-net.dhs.org/index.html ----------------------------------------

21 years

Slightly OT: tips for fabricating with plexiglass?

by news＠computercollector.com

It's only "slightly" off-topic because what I'm building is a new case for my Apple 1 "Replica 1" board. I've heard some horror stories about whole (expensive!) sheets of plexiglass simply breaking in half when incorrectly drilled through. The guy at the plastic supply company tried selling me a special drill bit, but I'm hesitant about that. Does anyone has hands-on experience and tips (vs. just speculation) about working with this stuff? This computer will be on display as some public events, so the final appearance is very important. ===== Tell your friends about the Computer Collector Newsletter! -- It's free and we'll never send spam or share your email address -- Publishing every Monday(-ish), ask about writing for us -- Mainframes to videogames, hardware and software, we cover it all -- W: http://news.computercollector.com E: news(a)computercollector.com -- 653 readers and counting!

21 years, 1 month

4 floppy disk drives on a PC?

by Innfogra＠aol.com

Western Digital made a 4 floppy controller for this. It is the 1002A-FOX F002 / 004 according to my 1996 CSC Hard Drive Bible. They say: F002 controls 4 floppys only. F004 has a BIOS on card which permits installation of 1.2 and 1.44 MB drives in XT machines that normally only support 360K or 720K drives. A note at the bottom: Uses WS-37C65 cchip, works well in 286/386 machines. You might look for one of those. Paxton Astoria, OR

21 years, 1 month

Slightly OT: tips for fabricating with plexiglass?

by bobcaar＠softhome.net

A circular saw can also be used to cut plexiglass easily. Just use a regular plywood blade, but put it on backwards and leave the protective film on/use tape where you make the cut. T.H.x. Devon

21 years, 1 month

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test-drb January 2005