Author Topic: IBM PC AT Service and Repair Video From 1984  (Read 13739 times)

0 Members and 1 Guest are viewing this topic.

Offline VK3DRB

  • Super Contributor
  • ***
  • Posts: 1770
  • Country: au
Re: IBM PC AT Service and Repair Video From 1984
« Reply #25 on: October 14, 2015, 12:49:15 am »
I was an engineer at IBM in a town called Wangaratta where we made the PC-AT for Australasia. They were prosperous days, and the profitability back then was big for IBM because there was not much competition. The ISA bus timing specs were not made public, so the IBM clones often were not IBM compatible. Besides, in those days there was a mantra by IBM - "No one ever got fired for buying IBM.", so sales were strong.

I don't remember too much about the 80286 motherboard. I think it has a trim cap for the 14.2818 MHz oscillator that was adjusted using the HP3065 ICT. Every board was burned in for 12 hours, dynamically tested up to 70 deg C in Blue-M chambers.

Oh, yes, the advanced diagnostics diskette. I had the source code to the advanced diagnostics, the BIOS and DOS, stored on a massive 200MB hard disk.

The plant was a great place to work, where we were like one big family. Colleagues even came out to help me build my house on 5 acres not far from the plant. We all looked out for one another and there was a level of camaraderie and passion for success in the business you would not see too much today. The social club there was like no other. The plant is long gone, IBM is long gone, the people are long gone and the electronics manufacturing scene in Australia is a fraction of what is used to be.

Ironically, that plant was the biggest exporter of non primary produce in the entire country in 1995. Five years later it was closed and anyone who remained lost their job.
 

Offline AF6LJ

  • Supporter
  • ****
  • Posts: 2903
  • Country: us
Re: IBM PC AT Service and Repair Video From 1984
« Reply #26 on: October 14, 2015, 01:01:37 am »
The electronics business was a lot different back then. I have fond memories of working at the division of oral Corp I worked at. :)
Thanks you brought back some fond memories.
Sue AF6LJ
Test Equipment Addict, And Proud Of It.
 

Offline blueskull

  • Supporter
  • ****
  • Posts: 13863
  • Country: cn
  • Power Electronics Guy
Re: IBM PC AT Service and Repair Video From 1984
« Reply #27 on: October 14, 2015, 01:35:28 am »
At 16:00, the TOY clock battery is a Li-MnO2 type, what Panasonic calls "CR". These were considered new at the time: they were first marketed in Japan during the mid-'70s.
At 18:00, you can see that the DRAM chips are stacked piggyback.

So... The first "MCM" package lol?  ;D
 

Offline zapta

  • Super Contributor
  • ***
  • Posts: 6004
  • Country: us
Re: IBM PC AT Service and Repair Video From 1984
« Reply #28 on: October 14, 2015, 02:47:21 am »
I don't remember too much about the 80286 motherboard. I think it has a trim cap for the 14.2818 MHz oscillator that was adjusted using the HP3065 ICT. Every board was burned in for 12 hours, dynamically tested up to 70 deg C in Blue-M chambers.

I designed once a medical diagnostic image processing system on an AT computer. Coming from the Motorola 68000/Unix world I naively assumed that we can buy as much memory as we need. I was very disappointed when I installed a memory card with a few megs of memory and the program got only 760K or so of RAM.  We had to implement memory block swapping between main memory and extended memory that required bios trickery and CPU reset on each swap. I never appreciated the X86 architecture. It was kludgy.
Drain the swamp.
 

Offline joeqsmith

  • Super Contributor
  • ***
  • Posts: 6462
  • Country: us
Re: IBM PC AT Service and Repair Video From 1984
« Reply #29 on: October 14, 2015, 03:20:04 am »
After they finally changed the BIOS to support an external device, our first hard drive for the PC was the Corvus.  Maybe 10 - 14" platters?  Seems like two of them in the drive.  Guessing 5 meg of storage for our DBASE application?   :palm:   

I was using a pair of Quantum Q2080s with the SA2000 bus on my AT.   These were 8" drives. 

With IBM making the BIOS and schematics available, I hacked these machines for many years to come.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

  • Super Contributor
  • ***
  • Posts: 6462
  • Country: us
Re: IBM PC AT Service and Repair Video From 1984
« Reply #30 on: October 14, 2015, 04:25:58 am »
The two 8" drives, located on the right, were as large as my AT computer.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8596
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: IBM PC AT Service and Repair Video From 1984
« Reply #31 on: October 14, 2015, 05:08:22 pm »
Those drives are whoppers alright. My AT had the same case.
I TEA.
 

Offline VK3DRB

  • Super Contributor
  • ***
  • Posts: 1770
  • Country: au
Re: IBM PC AT Service and Repair Video From 1984
« Reply #32 on: October 15, 2015, 06:49:22 am »
I don't remember too much about the 80286 motherboard. I think it has a trim cap for the 14.2818 MHz oscillator that was adjusted using the HP3065 ICT. Every board was burned in for 12 hours, dynamically tested up to 70 deg C in Blue-M chambers.

I designed once a medical diagnostic image processing system on an AT computer. Coming from the Motorola 68000/Unix world I naively assumed that we can buy as much memory as we need. I was very disappointed when I installed a memory card with a few megs of memory and the program got only 760K or so of RAM.  We had to implement memory block swapping between main memory and extended memory that required bios trickery and CPU reset on each swap. I never appreciated the X86 architecture. It was kludgy.

Too right it was cludgy. In those days I had to write programs occasionally in Assembly Language, right up until the 80386. Segmented addressing was a pain. I don't know if Intel's i7 for example still supports real mode (ie: run a genuine version of DOS. I guess one could try to load up an original IBM of Microsoft DOS and see if it works.... too much bother maybe. I don't think these newer processors could boot up in real mode and then switch to protected mode as in the old days.

IBM should have gone with the much superior 68000. From a programming and performance perspective I think using the Intel x86 was a mistake.

We are getting old. I had a drongo from India phone me alleging he was from "Microsoft Help Desk" and my computer was infecting the entire Internet. I followed his instructions but I told him I cannot find the start menu button, and that I am running the very latest version of Microsoft DOS. The idiot and his Indian Mafia boss had absolutely no idea what DOS was. They told me DOS does not exist and to open an internet browser. After confusing the heck out of these tossers, they eventually hanged up on me just after telling me I am a f*@%$&! who knows nothing.  ;D

I diverge, but another trick is to put on 90 year old's voice and tell them for example "We don't have one of those silly computer things in Happy Acres Nursing Home. If you tell me what one looks like, maybe I can phone up my grandson to find one and we can call you back." They hang up immediately.
 

Offline helius

  • Super Contributor
  • ***
  • Posts: 3015
  • Country: us
Re: IBM PC AT Service and Repair Video From 1984
« Reply #33 on: October 15, 2015, 03:13:43 pm »
So... The first "MCM" package lol?  ;D
Perhaps not the first; IBM had patents on MCM technologies in the '60s (Shockley had some even earlier). But they are an interesting last-minute kludge. The top and bottom packages have different pads bonded out so that they can be soldered directly together.
Now we have Hybrid Memory Cube and HBM where the dies are thinned and stacked together quite deep, making 3D microcircuits a reality.
 

Offline Halcyon

  • Global Moderator
  • *****
  • Posts: 4013
  • Country: au
Re: IBM PC AT Service and Repair Video From 1984
« Reply #34 on: October 16, 2015, 03:16:02 am »
I had a drongo from India phone me alleging he was from "Microsoft Help Desk" and my computer was infecting the entire Internet.

We get these from time to time at work and you can tell they are just using an auto-dialler. The phones in our office have more or less a sequential numbering plan, so after each hang-up you'll hear the next phone ring with the same rubbish, that'll continue for about 5 minutes. They're quick to hang up when you tell them that they've called a government department.

In this day and age, I don't know why law enforcement, banks and telcos can't get together and create some "bogus" credit card numbers which they can give to the scammers and trace the transactions in almost real time.
« Last Edit: October 16, 2015, 03:18:19 am by Halcyon »
 

Offline German_EE

  • Super Contributor
  • ***
  • Posts: 2400
  • Country: de
Re: IBM PC AT Service and Repair Video From 1984
« Reply #35 on: October 16, 2015, 10:37:39 am »
Here are some credit card numbers to get you started:

https://www.paypalobjects.com/en_US/vhelp/paypalmanager_help/credit_card_numbers.htm

https://www.auricsystems.com/media/filer_public/87/dd/87ddca0f-1d22-4ea8-8865-95f7e9d4c541/samplecreditcards.pdf

http://www.getcreditcardnumbers.com/

Have fun  :) One thing I miss living in a non-English speaking country (well, officially) are the scam callers. I've never had a call from Heinrich or Helmut at Microsoft telling me that my copy of MS Windows has a problem but then I run Linux so that would only confuse them.
Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.

Warren Buffett
 

Offline VK3DRB

  • Super Contributor
  • ***
  • Posts: 1770
  • Country: au
Re: IBM PC AT Service and Repair Video From 1984
« Reply #36 on: October 16, 2015, 12:21:40 pm »
I had a drongo from India phone me alleging he was from "Microsoft Help Desk" and my computer was infecting the entire Internet.

We get these from time to time at work and you can tell they are just using an auto-dialler. The phones in our office have more or less a sequential numbering plan, so after each hang-up you'll hear the next phone ring with the same rubbish, that'll continue for about 5 minutes. They're quick to hang up when you tell them that they've called a government department.

In this day and age, I don't know why law enforcement, banks and telcos can't get together and create some "bogus" credit card numbers which they can give to the scammers and trace the transactions in almost real time.

The solution to this endless barrage of Indian scam merchants is simple. The Australian government should block all incoming calls from India, except those on a new "Do Call Register" specifically targeted at India. Therefore the Indians who live here and have relatives overseas simply place their relatives number on the register so it is not blocked. Numbers without caller ID from India are blocked. The "Do Call Register" stays until the Indian government cleans up the problem.

 

Offline AF6LJ

  • Supporter
  • ****
  • Posts: 2903
  • Country: us
Re: IBM PC AT Service and Repair Video From 1984
« Reply #37 on: October 16, 2015, 12:59:17 pm »
The easiest answer is to to simply tell them you do not have Windows, you live in a mud hut.
If they still don't get it. Put them on hold with the sound track from a slaughter house.
Sue AF6LJ
Test Equipment Addict, And Proud Of It.
 

Offline idpromnut

  • Supporter
  • ****
  • Posts: 610
  • Country: ca
Re: IBM PC AT Service and Repair Video From 1984
« Reply #38 on: October 16, 2015, 03:11:41 pm »
I still have the grey book (technical reference I think it was?). Interesting read :)
 

Offline SeanB

  • Super Contributor
  • ***
  • Posts: 15397
  • Country: za
Re: IBM PC AT Service and Repair Video From 1984
« Reply #39 on: October 16, 2015, 05:31:56 pm »
With the IBM PC you could also get a very nice clock kit, which did not use up any of those scarce ISA slots to hold a clock with battery back up. Dallas Semiconductor made a clock socket, where you simply removed any 28 pin EPROm and put it back in with this socket installed. then you knocked using a special sequence of accesses, and you got a serial data stream on D0 where it held the lime as a clocked binary stream. Writing the data was the same simply using a write to the EPROM ( non volatile so it never did anything, but was still going to have /CS on the chip which was all that mattered along with the pattern of data on the address and data lines).

Had a small program on the hard disc which would simply be run during boot which did the knocking, got current time and date then set the PC clock using it, then it just left a DOS hook that handled the clock setting built in DOS instruction instead of the default one.

Was pretty expensive IIRC, and was superceded soon after release by the inclusion of a RTC in the 80286 application note. Dallas then made a battery backed RAM that replaced this chip, and this was very popular, still in production today and it, and it's variants, are in a lot of equipment as battery backed RAM and a clock.

Interesting aside, I did get a digital counter, that was supplied in a low power state to give long storage life of the internal lithium cell. Display was working from manufacture, just showed the word "Sleeping" until you pressed the front panel reset, which turned on an internal high value pull up on the count line. When I do have to change the battery ( it might do 15 years though) it will probably go back to that display again.
 

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8596
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: IBM PC AT Service and Repair Video From 1984
« Reply #40 on: October 16, 2015, 07:34:50 pm »
I still have the grey book (technical reference I think it was?). Interesting read :)

That's the one. I never tried finding scans of them, but they're probably around.
I TEA.
 

Online bingo600

  • Super Contributor
  • ***
  • Posts: 1478
  • Country: dk
Re: IBM PC AT Service and Repair Video From 1984
« Reply #41 on: October 17, 2015, 02:13:29 pm »
I still have the "Blue book too" XT-Ref i think

And this one as pdf : 1502494_PC_AT_Technical_Reference_Mar84.pdf  (27MB)

Saw it here : http://bitsavers.trailing-edge.com/pdf/ibm/pc/at/1502494_PC_AT_Technical_Reference_Mar84.pdf
/Bingo


« Last Edit: October 17, 2015, 02:22:32 pm by bingo600 »
 

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8596
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: IBM PC AT Service and Repair Video From 1984
« Reply #42 on: October 18, 2015, 03:42:57 am »
Thanks, Bingo!
I TEA.
 

Offline Halcyon

  • Global Moderator
  • *****
  • Posts: 4013
  • Country: au
Re: IBM PC AT Service and Repair Video From 1984
« Reply #43 on: October 18, 2015, 03:47:11 am »
The solution to this endless barrage of Indian scam merchants is simple. The Australian government should block all incoming calls from India, except those on a new "Do Call Register" specifically targeted at India. Therefore the Indians who live here and have relatives overseas simply place their relatives number on the register so it is not blocked. Numbers without caller ID from India are blocked. The "Do Call Register" stays until the Indian government cleans up the problem.

All well and good however a lot of these calls are made over VOIP services, which can appear to originate from a domestic number.
 

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8596
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: IBM PC AT Service and Repair Video From 1984
« Reply #44 on: October 18, 2015, 03:52:11 am »
I've heard that they get really bent out of shape if you lead them on. I look forward to the day they call me. Maybe I'll boot up my Atari 800XL.
I TEA.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf