Author Topic: Tektronix 4052-4054 System Test Fixture  (Read 664 times)

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Offline mmcgraw74

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Tektronix 4052-4054 System Test Fixture
« on: July 19, 2019, 12:59:19 am »
I like the 1970's/early 1980's Tektronix 4051, 4052 and 4054 computers. 
I used one in the 1970's and bought a 4052 and 4054 with some accessories in 2000.

One of the accessories I picked up was a Tektronix 4052/4054 System Test Fixture - since I had the 4052 and 4054 that needed repair.

I've since repaired the 4052 and 4054 - but never found any documentation on using the System Test Fixture.
I've checked the 4052 and 4054 Service Manuals - and they don't mention this test fixture.  Maybe it was just for the factory?

There was a 4051 System Test Fixture and the 4051 Service Manual has a section on using it to debug DRAM memory.

Here is a picture of my 4052/4054 System Test Fixture:



Inside are two boards - one has the ribbon cables attached and includes three EEPROMs that I downloaded and posted on my Tektronix 4051/4052/4054 Program archives github site in a 4052 System Test folder:
https://github.com/mmcgraw74/Tektronix-4051-4052-4054-Program-Files

The second board has the keypad, LEDs, switches, and includes a Motorola 6800 CPU (no surprise - Tektronix 4051 computer had a 6800 CPU).



Has anyone seen any documentation for this Tektronix computer tester?
 

Offline Stray Electron

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Re: Tektronix 4052-4054 System Test Fixture
« Reply #1 on: July 19, 2019, 01:17:49 am »
  Wow!  Interesting find. Where did you find that?

  I had two working Tektronix 4051s with the 8" floppy disk disk drives and other peripherals and manuals but I traded them off to a computer collector. I expect that he still has them but I haven't talked to him in years.  I also had a 4052 that came from Kennedy Space Center (the Charlie Bell sale if any of you know what that was) but I never got around to testing to see if it worked before it was stolen.

  I had a big stack of manuals for the 4051 (but not the SM as far as I recall) but I've never seen the Test Fixture mentioned but from the markings on the keys of your's, it appear to be a programmers "front panel" that will let you single step programs and examine and change memory addresses and the like.  Did you look at the connectors and see where they might plug into a 4051? I expect that it replaces the 4051s CPU and/or ROM and takes complete control of the 4061.  I never had mine open so I have no idea what the internal connectors looked like.
 

Offline mmcgraw74

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Re: Tektronix 4052-4054 System Test Fixture
« Reply #2 on: July 19, 2019, 01:45:10 am »
The 4052 and 4054 computers were custom AMD 2901 bit-slice architecture that emulated the 6800 instruction set but added sixteen 16-bit registers, new 16-bit instructions and hardware floating point instructions.  In addition they doubled the memory space to 128KB and had 64KB of BASIC ROM and up to 64KB of DRAM.

Here is a photo I took recently of my Tektronix 4054 - that I upgraded to a 4054A which was the last of this series.
The 4054 was introduced in 1979 and had Tektronix storage tube technology - 4096x3072 addressable graphics!

 I had just repaired two 4907 File Manager 8 inch floppy disk systems and a 4924 GPIB Tape drive (3M DC300 cartridges).



My collection also includes working Tektronix 4663 multi-pen plotter, hard copy unit, digitizing tablet and joystick.

I have been recovering 40 year old program tapes - changing the drive belts - and posting the recovered programs on my github site (link in first post in this thread).
 
 
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Offline ebastler

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Re: Tektronix 4052-4054 System Test Fixture
« Reply #3 on: July 19, 2019, 05:55:22 am »
@mmcgraw74, I don't see the linked images at vcfed.org in your posts above. This might be temporary, if something is wrong in their forum at the moment, or maybe they don't like the deep linking to images/attachments?

Can others see the images? Or could you copy them and add to your posts as an attachment please?

Edit: Works fine now, so most likely is was just some temporary issue on the vcfed server.
« Last Edit: July 19, 2019, 06:59:01 pm by ebastler »
 

Offline guenthert

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Re: Tektronix 4052-4054 System Test Fixture
« Reply #4 on: July 19, 2019, 05:27:52 pm »
@mmcgraw74, I don't see the linked images at vcfed.org in your posts above. [..]
Works fine here (USA, Chrome browser).
 

Offline ebastler

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Re: Tektronix 4052-4054 System Test Fixture
« Reply #5 on: July 19, 2019, 06:57:46 pm »
@mmcgraw74, I don't see the linked images at vcfed.org in your posts above. [..]
Works fine here (USA, Chrome browser).

Thanks for confirming -- they now display nicely for me. Same place and machine I used earlier today (Germany, Firefox), so it must have been some temporary glitch.
 

Offline mmcgraw74

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Re: Tektronix 4052-4054 System Test Fixture
« Reply #6 on: August 14, 2019, 11:40:18 am »
  Wow!  Interesting find. Where did you find that?

  I had two working Tektronix 4051s with the 8" floppy disk disk drives and other peripherals and manuals but I traded them off to a computer collector. I expect that he still has them but I haven't talked to him in years.  I also had a 4052 that came from Kennedy Space Center (the Charlie Bell sale if any of you know what that was) but I never got around to testing to see if it worked before it was stolen.

  I had a big stack of manuals for the 4051 (but not the SM as far as I recall) but I've never seen the Test Fixture mentioned but from the markings on the keys of your's, it appear to be a programmers "front panel" that will let you single step programs and examine and change memory addresses and the like.  Did you look at the connectors and see where they might plug into a 4051? I expect that it replaces the 4051s CPU and/or ROM and takes complete control of the 4061.  I never had mine open so I have no idea what the internal connectors looked like.

My first retirement was in 1999 and I found and acquired a 4052 from an Arkansas medical school auction and then my 4054 in an EBAY auction - for $7!

The 4052 purchase included a 4631 printer and a custom rolling cart - currently holding the 4054 in the photo above and the printer.

I'm trying to troubleshoot the 4052 display issues - and have the keyboard removed.  The edge of the ALU board containing the four AMD 2901 bit-slice microprocessors is visible and has four 10 pin headers.  Since the Test Fixture has four 10-pin headers and an 8-pin header, it seems possible that the Test Fixture might plug into those connectors.  However the hand-printed connector labels on the cables don't match the connector numbers on the ALU board. 

I have looked at the 4054 service manual schematics - those headers are shown as test points on the ALU board and do include address, data and control signals - which is promising.

Examining the two boards in the test fixture - I can follow the address and data LED signals to the internal ribbon cables from the keyboard/display board to the second board - but the discrete logic on the second board scrambles the signals to the external ribbon cables, so I'm not ready to try to connect the Test Fixture to my 4052 yet.
 


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