test-drb December 2002

test-drb@ccmp.vtda.org

250 participants
519 discussions

Floppy disk media density/format mismatching

by ian_primus＠yahoo.com

I was hunting around on ebay, and I found this quite by accident. http://cgi.ebay.com/ws/ eBayISAPI.dll?ViewItem&category=4610&item=2085201851 It is an auction for some reproduction Apple Lisa system disks. The guy certainly did a good job copying the labels, but I really wonder about the data on them - the disks he used are high density floppies. I always thought that if you format a high density floppy for low density that it will work for a while, then the data will become corrupt due to the different magnetic properties of the media. I know that this is true on 5 1/4 media, I used a high density disk in a Commodore 64 by mistake once, and it didn't work very well. I also remember back when high density 3 1/2" floppies were pretty expensive, I used to buy low density disks and drill holes in the other corner so I could reformat them for high density. It worked just fine, and those disks still work. Can anyone shed any light on the subject? Ian Primus ian_primus(a)yahoo.com

21 years, 4 months

Hi!/ Sharing the technology/ LK401/ Thanks!

by pete＠dunnington.u-net.com

On Dec 31, 13:03, Justin wrote: > > Oops. Sounds like you have an LK450, LK461 or LK471, not an LK401. LK401 > > uses a DEC protocol, the others are PS/2-style keyboards. They're not > > interchangeable, I'm afraid. There should be a label on the underside, > > with three barcodes, the top barcode being the model number. Does it say > > LK401, or something a little different? > > You are the only one to say it speaks DEC and not ps/2 though it has a > ps/2 connector. The circuitboard looks like that of a LK201 when I take > it apart. They all look fairly similar. What I meant is that the ones with PS/2-style plugs normally use PS/2 protocol, and the ones with an RJ11 use a different, proprietary protocol. My PS/2 ones are at work so I can't easily check. The only ones I have here are RJ11 LK401s, from VT420s. > It does have 3 barcodes on the bottom. It isn't made by DEC but in > Mexico by someone My LK401s, one UK layout, one German, both say Made in Mexico but they're still DEC. > But it ways 5.0 VDC, so I guess it must be ps/2 and not dec style since > dec has 12 vdc? Sorry, I can't remember. -- Pete Peter Turnbull Network Manager University of York

21 years, 4 months

A better new year

by lgwalker＠mts.net

For a better new year, all that has to be done is make pretzels a couple of centimeters thicker. Most all the world will be delighted. A war-free year to all. Lawrence May you get halfway to heaven, before Satan learns you're dead or 3/4s of the way to the bar before your wife finds you've gone out. lgwalker(a)mts.net bigwalk_ca(a)yahoo.com

21 years, 4 months

substitute for TI TIL306/307 Display?

by rigdonj＠cfl.rr.com

Does anyone know of another display that can be substituted for the TIL 306/307? Here is a data sheet for the 306/307 in case you have a question about it, <www.alltronics.com/download/TIL306.pdf>. Joe

21 years, 4 months

Section 9? (HP 1000 power supply)

by glenslick＠hotmail.com

That is good information to know. I never had a plug to look at and check the resister inside. I think I was told 880 ohms, but that doesn't appear to be a standard resister value while 820 ohms is a standard value. Now that I know the real value to use I will build a real plug instead of just using some test clips and a trimpot for now. -Glen >Here I sit looking at a little black square 3x3 plug, HP p/n >12991-60002 (stamped in white ink on one side of the hood). > >Inside the hood (visible through the hole in the back) there is only a >1/4W resistor connected to pins 4 and 6, which matches Glen's >description. Bands are gray, red, brown, gold. Hmm, 820 ohms? >Measures as 823 ohms on my cheap digital multimeter. > >-Frank McConnell _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963

21 years, 4 months

Section 9? (HP 1000 power supply)

by fmc＠reanimators.org

"Glen S" <glenslick(a)hotmail.com> wrote: > But someone else on the list told me that something like an 880ohm resister > across the left most and right most terminals of the middle row of the > battery connector input would trigger the power supply to power up all of > the way. That did the trick for the HP 1000 / 2117F that I have. Here I sit looking at a little black square 3x3 plug, HP p/n 12991-60002 (stamped in white ink on one side of the hood). Inside the hood (visible through the hole in the back) there is only a 1/4W resistor connected to pins 4 and 6, which matches Glen's description. Bands are gray, red, brown, gold. Hmm, 820 ohms? Measures as 823 ohms on my cheap digital multimeter. -Frank McConnell

21 years, 4 months

Section 9?

by jimw＠agora.rdrop.com

Ok, a tad cryptic. <G> I've found the .pdf version of the HP 1000/M/E/F Engineering Docs, but every copy I've been able to access is missing section 9 (still can't keep track of the Roman Numerals they mark the sections with) which covers the power supply. There seems something a tad 'twinky' with mine, tho I seem to recall at one point someone had directed me to a jumper/resistor that needed to be installed at the 'Battery Input' connector on the rear to wake something up, but of course now that I'm working on it I can't find anything... Help??? -jim --- jimw(a)agora.rdrop.com The Computer Garage - http://www.rdrop.com/~jimw

21 years, 4 months

Anyone have any experience replacing a Dallas 1287 with a 12887?

by dwightk.elvey＠amd.com

>From: "Ethan Dicks" <erd_6502(a)yahoo.com> > > >While attempting to revive a Compaq 286/SLT laptop for use as a >front-end for my UP600a programmer, I have found that the battery >on the DS1287 has died (no suprise there). What sucks is that >even after I run the floppy-based setup utility, after a reboot >(not a power-off cycle), the machine forgets what I just set, >both the data and time, and the geometry of the A: drive. Seeing >as how it thinks there's a 5.25" floppy and it's really a 3.5" >high-density drive at the end of the cable, as you can imagine, >it won't reliably read disks. > >So... I have ordered a replacement DS12887 since they no longer make/ship >the DS1287. Couple of interesting app notes here: > > http://www.maxim-ic.com/appnotes.cfm/appnote_number/562 > http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2681 > >What I'm wondering is if anyone on the list has ever replaced a DS1287 >with a DS12887. One of the sheets seems to suggest that I'll need >an updated BIOS ROM (clearly not available for a 286 laptop) to drive >the extra stuff associated with the enhanced century rollover. > >Alternatively, has anyone here successfully performed surgery on a Dallas >module? I have disconnected the battery from a Mostek 48T02 from a SPARC >and soldered on an external Lithium cell, but the packaging makes it easy >to get access to the battery wires coming down from the top (I even put >the battery on a 9V battery snap so it's easier to replace) I haven't >heard of anyone doing this for the more sealed Dallas modules. > >So... anybody else suffer though this? > >-ethan > > Hi In a search of the news groups, I found an article by a fellow that had done surgery on a number of different modules. One thing that seemed to be constant was that they put the battery in a number of different locations within these types of devices. If I was going to hack mine, I first take it to a printed circuit building shop. These guys usually have a small X-ray machine for inspecting solder joints. With one of these, you can locate where the vital parts of the chip are. You can then use a Dremel to grind into it and connect an external 3V cell. Dwight

21 years, 4 months

Lisa jittery screens

by jingber＠ix.netcom.com

I have two different Lisa machines and both have a jittery display (one 1.2AMP PSU, 1 1.8 AMP PSU). I've followed the instructions in the Sun Rem. guide to adjust the power supply output. This works immediately after the adjustment, but the problem gradually comes back over time. I adjusted both machines around the September timeframe and the jitters have back on both machines. I'd like to get both of these machines in top-shape so I can have them running at my New Years party =) Before I go through the adjustment again, is there anything else I should be checking? I've also tried adjusting the V.Hold, but this doesn't seem to make a difference. Maybe I'm not using a precise enough adjustment? Thanks, Jeff

21 years, 4 months

Snoopy was Re: M200 interfacing

by Innfogra＠aol.com

In a message dated 12/30/02 1:13:16 PM Pacific Standard Time, cisin(a)xenosoft.com writes: > Don't forget how significant a part of the culture of the history of > computers is contained in all of those stupid line printer graphic > pictures of Snoopy ... Ah Yes, The first thing I printed out with my Litton 1251 when I got it into my living room in the mid 80s was a Snoopy calendar. All in punched tape. Nice machine, wished I had kept it. Paul Pierce has a Litton 1231 in his collection for when he gets his museum started in PDX. Punched tape, drum memory, console wi printer, Yum Yum... Paxton Astoria, OR

21 years, 4 months

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test-drb December 2002