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Thread: Tektronix 4662 plotter is Working!

  1. #1

    Default Tektronix 4662 plotter is Working!

    I finally figured out how to get my Tektronix 4662 plotter working with my 4054A computer using GPIB.

    There are four rotary switches on the back panel that configure either serial or GPIB capabilities. I finally figured out how to set the switches properly for GPIB from the 4662 service manual. Set A=0, B=0, C=0, D=3 to set the plotter to GPIB address 3 and work with the Tektronix 4050 GPIB MSA codes.

    Now any Tektronix program that PRINTs to the screen can be modified to PLOT, by changing the PRINT statements to PRINT @3:

    I quickly edited one of my BASIC programs that port Tektronix 4114 terminal graphics to print on the 4050 computer screen, to plot on my 4662.

    Here is a video and photo of the first plot: Snoopy, the Red Baron

    https://youtu.be/hGmodCc9Hh4

    Last edited by nikola-wan; November 11th, 2019 at 07:27 PM.

  2. #2

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    This is my setup with my 4054A computer connected to my 4662 (with multi-pen Option 31), right after plotting Snoopy.
    You can read the first page of the program - it is all PRINT statements. PRINT @3,21 is a MOVE and PRINT @3,20 is a DRAW to the plotter.

    You can see the Faber Castell pen in my 3D printed pen adapter installed in the plotter for that plot.



    Next photo shows the Staedtler pen adapter I created to the left of a Tektronix pen and adapter. On the right is the Faber Castell Pitt Artist Pen and adapter I created.
    I had purchased two different Staedtler HP Plotter pen sets 20 years ago. Almost all these pens still work. Secret seems to be storing them capped and horizontal.

    I purchased the box of Pitt Artist Pens at a Michael's store a couple of weeks ago, plus the XS pen. These pens worked pretty well, although they skipped a little at high speed. The Staedtler pens worked better and didn't skip.



    Next photo shows both Staedtler pen sets AND a package of Tektronix plotter pens I had forgotten about. Many of the Tektronix pens still work! I printed Snoopy in the video with a Tektronix blue pen from this package.

    The transparent 'pen' at the top of the photo is a Tektronix 4662 digitizing pen. I used this to digitize a Battlestar Galactica starfighter for my "Vipers on Patrol" BASIC program 20 years ago.



    Next photo is a closeup of the digitizing pen - you can see the cross-hairs are magnified on the pen package below.



    This is a photo of the 11x17 Tektronix plotter paper I bought when I found my 4662 plotter 20 years ago:



    I have posted my 3D printed plotter pen adapter STL files on my github Tektronix program repository in a Tektronix 4662 folder:

    https://github.com/mmcgraw74/Tektron...-Program-Files

  3. #3

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    Since the Tektronix 4662 Plotter Service Manual scan by the Living Computers Museum in Seattle is now posted on bitsavers.org (thanks Al Kossow!) at:

    http://bitsavers.trailing-edge.com/p...nual_Jul83.pdf

    I used it to disassemble my 4662 plotter to investigate why the multi-pen carousel stopped working.

    I discovered the plastic sprocket on the stepper motor drive shaft for the carousel was split - so the motor was no longer rotating the pens.



    I tried superglue on the sprocket but it didn't hold.

    I found the sprocket in a google search and am waiting to hear back from the shop on price with shipping.

    Another suggestion from Dave Brown at the vintagetek.org museum was to epoxy the broken sprocket to the shaft as he did for their 4662 plotter sprocket:

    https://vintagetek.org/repairing-knobs/

  4. #4

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    While my 4662 plotter was open, I took the opportunity to download all four 2732A EPROMs.

    These are version -01 firmware and are installed on a separate System Memory board - and the mainboard has no ROMs.

    I have uploaded the new ROM images to my github site in the 4662 plotter folder:

    Tektronix 4662 Plotter ROMs version -01

    In addition I posted photos of the System Memory board with the EPROM's installed:



    Here is the top view of my 4662 plotter with the cover removed.
    The two ribbon cables from the System Memory board to the Mainboard connect the EPROMs to the 6800 CPU.
    The third ribbon cable connects to the Opt 31 multi-pen changer board in the bottom left of the photo.



    You can see a whole row of empty sites for ROMs on the Mainboard between the two ribbon cables.
    In addition, there are only four 2114L 450 nsec 1Kx4 SRAMs on this version of the Mainboard.

    Last edited by nikola-wan; November 24th, 2019 at 08:33 AM. Reason: added SRAM speed

  5. #5
    Join Date
    Dec 2010
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    Default

    I have two 4662 plotters that came with some other Tektronix stuff that I picked up a few years ago (some 4170 CP/M-86 boxes). The plotters are rather grimy. I have never tried to clean them up and see if I could get them working.

    I just popped the covers to take a quick look. One has the same EPROM version labels that you have. It looks like all of the SRAM sockets might be populated on that one. The other one has hand written labels on the EPROMs. It is also missing the motor that drives the multi-pen carousel.

    Is it easy to remove the plotter bed to get access to the PCBs? I can't get a good look at the hand written EPROM labels without removing the plotter bed. These originally came from a Tektronix engineer and might be pre-production development items.

    EDIT: I took another look and realized it is easy to remove just the plotter bed simply by removing four screws. I originally thought the entire pen movement needed to be removed. I'll take a photo of the handwritten EPROM labels and dump them later.
    Last edited by gslick; November 24th, 2019 at 02:40 PM.

  6. #6
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    Default

    Quote Originally Posted by nikola-wan View Post
    I finally figured out how to get my Tektronix 4662 plotter working with my 4054A computer using GPIB.

    There are four rotary switches on the back panel that configure either serial or GPIB capabilities. I finally figured out how to set the switches properly for GPIB from the 4662 service manual. Set A=0, B=0, C=0, D=3 to set the plotter to GPIB address 3 and work with the Tektronix 4050 GPIB MSA codes.

    Now any Tektronix program that PRINTs to the screen can be modified to PLOT, by changing the PRINT statements to PRINT @3:

    I quickly edited one of my BASIC programs that port Tektronix 4114 terminal graphics to print on the 4050 computer screen, to plot on my 4662.

    Here is a video and photo of the first plot: Snoopy, the Red Baron

    https://youtu.be/hGmodCc9Hh4

    That Snoopy and the Marilyn M. must have been everywhere back in the day. Your Snoopy looks just line the one our ASR-33 used to put out only it was done with x's & o's. We didn't have access to a plotter.
    Surely not everyone was Kung-fu fighting

  7. #7
    Join Date
    Dec 2010
    Location
    Seattle, WA
    Posts
    1,849

    Default

    Here are the handwritten EPROM labels on the one 4662 plotter. That one also has a small ATN/DAV HOLDOFF board wired to the main PCB.

    EPROMS.jpg

    ATN-DAV.jpg

    bodge.jpg

  8. #8

    Default

    Quote Originally Posted by gslick View Post
    I have two 4662 plotters that came with some other Tektronix stuff that I picked up a few years ago (some 4170 CP/M-86 boxes). The plotters are rather grimy. I have never tried to clean them up and see if I could get them working.

    I just popped the covers to take a quick look. One has the same EPROM version labels that you have. It looks like all of the SRAM sockets might be populated on that one. The other one has hand written labels on the EPROMs. It is also missing the motor that drives the multi-pen carousel.

    Is it easy to remove the plotter bed to get access to the PCBs? I can't get a good look at the hand written EPROM labels without removing the plotter bed. These originally came from a Tektronix engineer and might be pre-production development items.

    EDIT: I took another look and realized it is easy to remove just the plotter bed simply by removing four screws. I originally thought the entire pen movement needed to be removed. I'll take a photo of the handwritten EPROM labels and dump them later.
    All the 4662 and 4663 plotter manuals including service manuals are now posted on bitsavers.org - thanks Al Kossow!!!!

    http://bitsavers.trailing-edge.com/pdf/tektronix/466x/

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