test-drb April 1999

test-drb@ccmp.vtda.org

170 participants
1190 discussions

by healyzh＠aracnet.com

OK, the good news is it didn't blow up when powered on, though did have a few worried minutes till I got smart and got out the console key, and turned it to a on possition :^) I just got done measuring the voltages and if I'm reading the manuals correctly the voltage levels are within limits. Flexprint Cable: +5.37V P1 Connector Pins Voltage Overvoltage Limit (according to BA11-A manual) 1-10 +5.05 +6.5 11-16 +11.92 +15.0 17,18 -11.91 -15.0 25,27 -14.97 -18.0 26,28 +15.11 +18.0 However the following pins seem reversed 23 GND SENSE 24 +5 SENSE I get nothing on the +5 SENSE, but I get +5.24V on the GND SENSE. What is up with that?!?!?! I'm possitive that I'm not the one that is reversed as I checked this several times. The voltages all are under the overvoltage limit, so I assume I'm OK on that note. Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)aracnet.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.dragonfire.net/~healyzh/ |

26 years

The "FIRST PC" and personal timelines (Was: And what were the 80s

by allisonp＠world.std.com

<console interface. In fact I don't know of a graphics card that was, thoug <on toward '82-83 there were a few with some of the more "capable" graphics <support chips like the NEC 7220 or that "BIG" Hitachi graphics chip, thoug <I never saw one except at a trade show. The 7220 was introduced early 1980 and volume ships were 5 months later. By 1983 it was well on it way to next generation. <Some of these were pretty demanding applications which quickly pointed up <the weakness in using 8-bit computers for multi-plane graphics. They also <pointed up the fact that decent high resolution color monitors cost about a <much as a house . . . well, not quite, but you get the idea. If you bough <one, you'd better keep the box, because you'd need a place to live when you <wife found out . . . We did a multibus baord with the first 7220s and we had a heck ofa time with the monitors as most really could not do the bandwidth and the .042 dot size didn't help! As to using a z80, it was awkward but doable though we designed with a 8086 in mind as we sourced that as well. By late 81 we were running a 4plane (1 megabit planes) graphics CPM86 with 512k of ram. The key was the system was cheap for the time considering it was multibus based. Allison

26 years

The "FIRST PC" and personal timelines (Was: And what were th

by allisonp＠world.std.com

< The ham radio or electronic hobbyist would have been more likely building <or adapting tube technology to solid state. Yes, they tended to be frontrunners but the various ARRL handbooks (I have many going back to '47) which tend to be a good indicater of the hot radio technology of the time. Aywho the transistor was far to expensive and to cranky to work with until the 60s. Some of the tranistors failings were they were poor at anything but audio and low RF and very expensive. I found it hard to find a good RF transistor until the mid-late 60s that weren't several bucks a peice. So there wes another little aspect of the technology that had to happen. devices that could do logical switching (tubes, transistors...) available in low enough prices and compact enough to consider. The first HOBBYIEST IC based frequency counters were not appearing until 1967 give or take 6 months. Now a frequency counter is a pretty trivial logical device but one that has immense value to radio folk. Again convergence of technology is one factor. Discussing the 50s is fairly pointless as even the portable transistor radio was a late 50s advent. Allison

26 years

Leaky nicad battery

by allisonp＠world.std.com

<I have an old PC which has a leaky nicad battery soldered to the PCB. There <stuff coming out of the battery, which has corroded the PCB traces near it <This is probably the reason why the machine doesn't work properly. Any mild acid works to neutralize the alkaline NICAd eletrolyte. I personally found lemon juice or vinegar effective and then washing the board well afterwards. Replace the battery! <guess I'll just have to solder some wires in place. Yep! Allison

26 years

DEC

by allisonp＠world.std.com

< I have a manual for PrintDirecter put out by Digital Products Inc-"the sub <Company" of Watertown, Ma. Was this a division of DEC ? I know there were <several companies with Digital in their name. No connection to Digital Equipment Corp, Maynard MA. there were no subsidiaries. Allison

26 years

building core

by allisonp＠world.std.com

<Ok, one step closer. The description of core in the PDP-8/a miniprocessor <users manual shows the wires going straight through the cores. Is this <correct? I'd expect the wire to make one or two turns around the core so <that the magnetic field it induced would be "inside" the torroid. Comments? So it's a fraction of a turn. There are reasons for not doing multiple turns. One being the size of the wire. another is adding turns increases the inductance of the "coil" and with literally hundreds of "coils" it would be very hard to get a good switching waveform. <What about driving voltages? I've got a +/- 36v @ 3amps supply here, the <PDP-8 uses its 15 volt supplies. I'm building a simply push-pull direct <coupled amp out of a couple of transistors to send the signal that Allison <drew. I'm using a Parallax BASIC Stamp to generate the waveforms (I could <use the HP but then it wouldn't be portable) It's current driven through the wire that is important. <Sense wire? Straight through the core or also with a wrap? Same as core plane. Actually for testing you could used a turn or two for the driving wire and the sense wire to make life easier(less drive, bigger signal) but for multiple cores you need to do the matrix as fractional turns. Allison

26 years

The "FIRST PC" and personal timelines (Was: And what were the 80s id AA20486; Fri, 23 Apr 1999 18:47:56 -0400

by allisonp＠world.std.com

<Ummm... must beg to differ here. While the SOL uses the VDM-1 circuitry, <it is an integral part of the main board rather than an S-100 add-on, and <I do not recall any variant offered that would have been minus the video <system. Oops, confused the systems. PT sole a board set that gave a virtual SOL but at S100 board level. The VDM-1 I have still works nicely in the Netronics Explorer 8085. In that case the SOL had the video locked in, that makes the point I was driving toward move valid. Allison

26 years

Semi-ot/Semi-odd game requrest

by review＠RyansPC.ryanspc.com

Hi. I've been thinking about asking this for a while, but never got around to it. When I moved, some of the floppies that were in my possession seemingly disappeared/didn't get shipped. In any case, I don't have them anymore. Most of the data was just personal stuff and/or backups, but there were two things in particular that I've permanently lost (both origonals and backups were together, as I didn't think of them getting stolen, but instead infected/defective) were Sid Meier's Civilization I from Microprose, the origional PC edition, as well as the origional PC edition of Castles I from (IIRC) Interplay. I have all applicable documentaiton, as well as a liscense, but just not the software. Would anyone be willing to either make copies of the disks or to email a compressed (either zip or .tgz or .tar.gz would be preferable) copy of the disks? For floppies, I'd be willing to pay the cost of floppies and mailing to Wash., DC, USA, however, the Internet method would probably be better. Also, if anyone knows a used software store where I could get a copy, htat'd also work out. Please eMail me privately at tim(a)thereviewguide.com. Thanks a billion, Tim D. Hotze

26 years

PDP-11/44 Boot ROMS

by healyzh＠aracnet.com

I've identified that I've got boot ROMS for the following 751A9 RL01 765A9 TU58 757A9 TU16,45,77,TE16 767A9 <-What is this one, the manual doesn't list it. I assume that I can boot RL02's with the RL01 ROMS. Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)aracnet.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.dragonfire.net/~healyzh/ |

26 years

PDP-11/44 Boot ROMS

by CLASSICCMP＠trailing-edge.com

>I've identified that I've got boot ROMS for the following > >751A9 RL01 >765A9 TU58 >757A9 TU16,45,77,TE16 >767A9 <-What is this one, the manual doesn't list it. The 767A9 is the UDA50 (and other third-party-MSCP-emulating board) bootstrap. >I assume that I can boot RL02's with the RL01 ROMS. Yes. In case you're looking for a list of boot ROM's, see: http://metalab.unc.edu/pub/academic/computer-science/history/pdp-11/hardwar… Tim.

26 years

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test-drb April 1999