test-drb October 2004

test-drb@ccmp.vtda.org

245 participants
540 discussions

The myth of the memory effect- was: NMIH batteries - was: Re: HP 25 and HP55

by dwight.elvey＠amd.com

Hi Tom >From: "Tom Peters" <tpeters(a)mixcom.com> > ---snip--- >2. NiCD batteries never had a memory effect either! Read the literature ---snip a lot of good stuff--- Thank you for mentioning this. I think, a lot of what people think of as memory is caused by unequal charging of battery stacks. As the cell that has the most charge remaining reaches full charge, the current through this cell reduces. The cell that has been lagging behind, never receives a full change. Flattening the stack lets them all start from a more equal playing field. The problem people miss with flattening is that if a cell is reverse charged, the depolarizers are at the wrong ends of the cells and the gas pressure builds up causing the burst seal to fail. Although, immediately after charging, this cell seems to work fine, within a month or so the cell will fail, simply because it dries out inside :( It may also leak on things. As I stated before, long term storage of NiCads is best done with them fully discharged. This keeps metal fingers from developing that cause the shorted cells that we often see. One can also store them at full charge because this tends to blow out any metal fingers that grow. The problem is that storing mostly discharged cell is the worst since there is both the voltage that causes the metal fingers to grow and not enough capacity to blow them out when they do short. Dwight

21 years

OT: Peter Packet

by patrick＠vintagecomputermarketplace.com

Definitely OT, but I think this is priceless... http://www.cisco.com/warp/public/779/edu/peterpacket2/deliverables/funland_p lay.htm Patrick

21 years

DEC Station almost

by KParker＠workcover.com

A while ago I picked up a DEC Station 5000/150 - it was just the main box and a couple of storage expansion boxes - one containing a floppy and hard drive and the other a tape drive and hard drive. I was most fortunate on the weekend and picked up a 19" colour Monitor for it. All I'm missing now are the keyboard and the mouse. Can anyone advise if these were proprietary devices for the DEC Stations or can I use something else. TIA!!!! ++++++++++ Kevin Parker Web Services Manager WorkCover Corporation p: 08 8233 2548 m: 0418 806 166 e: kparker(a)workcover.com w: www.workcover.com ++++++++++ ************************************************************************ This e-mail is intended for the use of the addressee only. It may contain information that is protected by legislated confidentiality and/or is legally privileged. If you are not the intended recipient you are prohibited from disseminating, distributing or copying this e-mail. Any opinion expressed in this e-mail may not necessarily be that of the WorkCover Corporation of South Australia. Although precautions have been taken, the sender cannot warrant that this e-mail or any files transmitted with it are free of viruses or any other defect. If you have received this e-mail in error, please notify the sender immediately by return e-mail and destroy the original e-mail and any copies. ************************************************************************

21 years

Commodore 8010 IEEE-488 Acoustic Modem ?

by dave3＠toadware.ca

Hi Ethan, >> I am looking for: >> >> - Information on the power supply - I did not get a power supply >> with the modem - it has a 5-pin DIN type connector. Can anyone >> give me the pinout and power requirements? >Can't help there, but worst case, it shouldn't be difficult to >reverse-engineer the power supply... if there is some kind of >regulator, it might take a wide range of voltages. If not, then >one of the pins is probably +5V. It's old enough that I wouldn't >assume it uses a C-64 supply or even the voltages for the C-64 >(+5VDC, 9VAC), but it's worth looking at. Thats my plan-B - but I'm hopeing someone has this modem and can at least measure the supplies - Sometimes older analog stuff uses "funny" voltages and it might not be obvious what the supplies are supposed to be - agreed that it should be easy to identify 5V for the logic - it appears to be "completely manual" with switches for Answer- Off-Originate, so I don't think there's much logic except for the IEEE interface. >> - Documentation? Anyone have a scan of the manual? >Not me; sorry. Perhaps on funet? Didn't find anything on funet - but I will continue to look. Not much mention of this device at all that I could find via google. >> - Information on how it is used ... What sort of IEEE device does it >> show up as? Is there "special software" that is used with it? etc.? > >Worst case, you could write a quick BASIC program to try OPENing all the >devices from 4 to 31 and see where it responds (once you get the power >issue resolved). Without docs, it'll be hard to tell if there are any >significant secondary addresses, though. Yeah - not that I have a burning desire to communiate at 300bps, but I like to get everything that I collect working ... I did find a couple of references to software for this modem, which I am trying to track down. I've never used an IEEE modem on a PET, so it might be "interesting" to try and figure it out on my own... >Nice find. I've never seen one. Good luck on the hunt for docs. Here's a picture I found ... I will be adding my own pics to my site on the next update (but I just updated it so it will be a while): http://www.commodore.ca/gallery/hardware/pet_acc_coupler1.JPG Regards, Dave -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ .

21 years

NMIH batteries - was: Re: HP 25 and HP55

by dwight.elvey＠amd.com

>From: "Dave Dunfield" <dave04a(a)dunfield.com> > >>>> -- I took apart the 25's battery pack and replaced the nicads with >>>> nickel metal hydride cells (the same ones I use in my camera) >>> >>> Not a good idea. Nickle metal hydrides need different types of >>> charging. The won't last long with a NiCad charging circuit. >> >>I won't charge them in the calculator, they are regular AA cells so I >>can remove them and put them in a proper charger. :^) > >Here's a question for battery guru's ... I have a gadget I built for >preventing "memory effect" in various nicad powered devices - mainly >ones like my Digicams which only discharge the battery 1/2 way (or >less) before complaining that the battery is low. > >It is basically two springy metal bars which lets me put up to 10 AA or >C cells in parallel to discharge (I've got portable @M and 70CM rigs powered >by a C cell pack), an Ammeter, a low resistance, and a stud rectifier diode. > >Basically, it draws about an amp from the cell when they are near fully >changed, and trickles down to nothing as they approach .7ish volts, and >never lets them go to zero. > Hi Actually, NiCad's can be discharged to zero without problems. It is tha back charging in stack, as batteries, that causes the problems. In fact, NiCad's are often shipped with shorting bars across the terminals. >I works REALLY well with nicads - I've got cells that I've been using in >my radios for many years and they still work very well (Prior to using >this, they would noticably lose capacity after a while)... > >But: It doesn't seem to be quite as effective with NMIH cells ... they >still seem to be losing capacity ... These cells shouldn't be discharged to zero. Just different technology. One thing you might try ( as an experiment ). Hit them with a momentary high current load. This is done on NiCad's to improve their performance and may have a similar effect on nickle metal hydrides. It does need to be controlled because like NiCad's, once the burst seal is broken, expect them to be worthless in a few months. Dwight > >Any explaination, comments etc.? > >Regards, >Dave > > >-- >dave04a (at) Dave Dunfield >dunfield (dot) Firmware development services & tools: www.dunfield.com >com Vintage computing equipment collector. > http://www.parse.com/~ddunfield/museum/index.html > > >

21 years

access to BIOS of DECpc

by GOOI＠oce.nl

Hi all, thanks for all the responses, I have some leads now. Here is a report what I tried so far. Searching the Internet, I found the setup files set320p and pwr320p for the DECpc 320P. Alas, the setup allows several items to be configured, but the hard disk is not one of them! Next, I found Ontrack DiskManager versions for IBM and for Microscience, but the IBM version stops because it does not detect a hard disk of their brand. BTW, my 2.5" hard disk is from HP, type C2965A. The Microscience version allows 7 different types to be set, but up till now I did not get satisfactory results. I can get to 50 Mb, but compared to the original hard disk (40Mb) that is not much gain, especially when you think that the C2965A is 420 Mb ...! I also have the version from Western Digital, EZ-Drive (Data Lifeguard) but this version also stops because the disk is not from WD. Not yet tried is a version from Fujitsu, and the version I received from Pete (thanks Pete!). I guess it's clear what I will be doing this weekend :-) thanks for all the help and advice, - Henk, PA8PDP.

21 years

PDP customer on Cleveland, OH needs urgent help

by unibus＠gmail.com

> From: Jay West <jwest(a)huey.classiccmp.org> > Just got a call from a PDP-11/05 customer in Cleveland OH. They are in a > crisis situation due to a dead 11/05. They suspect memory problems but > there may be power supply issues as well. > > If there is anyone local to them with 11/05 parts and or expertise, can > you please call me right away? > > Best number to reach me right now is 314-494-7338 > > This company is willing to pay for help as the 11/05 being down takes > their milling machine down. Probably too far away, but some thoughts. Be careful what cards you pull out as the power supply has a crowbar arrangement that trips if you have too light a load (DC supply line voltage rises above trip point). Case of refer to the manual and check the supply voltages. Relatively easy on the 11/05 if you have the maintenance manual. The processor & power supply can be checked by storing and executing instructions from the general registers. If you can't store/read from front panel you probably have a power supply problem or problems with that logic. If the problem is down to the processor boards you really need a hex width extension card and the maintenance cards to single step the processor. Core memory can be tested and then track down problems with a CRO if you can't board swap your way out of trouble. If caught with dead core and you have the 10-1/2" high processor unit can install later generation MUD then install a MOS memory board. Just have to move the power cabling.

21 years

Hardware (What Interests me....) was : (PDP-8/s on e-bay)

by Pres＠macro-inc.com

At 09:42 PM 10/21/2004, you wrote: > >>> HITS NAIL ON HEAD > >1) I know many hardware hackers who don't know a compiler from a debugger >[Thinking of some of my Ham buddies].... Debugger? Isn't that what printf("at step 2\r\n"); and while(!kbhit()); are for? >2) I tend to hit finger with hammer and from nail. You type good, must not be using hammer much, eh? :-) Ed K.

21 years

NMIH batteries - was: Re: HP 25 and HP55

by dave04a＠dunfield.com

At 06:59 22/10/2004 -0400, you wrote: >At 09:30 PM 10/21/2004, you wrote: >>But: It doesn't seem to be quite as effective with NMIH cells ... they >>still seem to be losing capacity ... >> >>Any explaination, comments etc.? > >NiCad are better than NiMH longevity wise. > >Here's link to place I found helpful in explaining: > >http://www.buchmann.ca/chap10-page1.asp Thanks Ed, Lots of useful information - I normally cycle/discharge the nicads every couple of months - looks like I want to space that out for the NMIH - I did not realize that they had so much less charge/discharge endurance (a fact that the manufacturers seem to have forgotten to mention in their comparisons). Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Vintage computing equipment collector. http://www.parse.com/~ddunfield/museum/index.html

21 years

NMIH batteries - was: Re: HP 25 and HP55

by dave04a＠dunfield.com

>>> -- I took apart the 25's battery pack and replaced the nicads with >>> nickel metal hydride cells (the same ones I use in my camera) >> >> Not a good idea. Nickle metal hydrides need different types of >> charging. The won't last long with a NiCad charging circuit. > >I won't charge them in the calculator, they are regular AA cells so I >can remove them and put them in a proper charger. :^) Here's a question for battery guru's ... I have a gadget I built for preventing "memory effect" in various nicad powered devices - mainly ones like my Digicams which only discharge the battery 1/2 way (or less) before complaining that the battery is low. It is basically two springy metal bars which lets me put up to 10 AA or C cells in parallel to discharge (I've got portable @M and 70CM rigs powered by a C cell pack), an Ammeter, a low resistance, and a stud rectifier diode. Basically, it draws about an amp from the cell when they are near fully changed, and trickles down to nothing as they approach .7ish volts, and never lets them go to zero. I works REALLY well with nicads - I've got cells that I've been using in my radios for many years and they still work very well (Prior to using this, they would noticably lose capacity after a while)... But: It doesn't seem to be quite as effective with NMIH cells ... they still seem to be losing capacity ... Any explaination, comments etc.? Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Vintage computing equipment collector. http://www.parse.com/~ddunfield/museum/index.html

21 years

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test-drb October 2004