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Thread: Tek 405x web-browser emulator

  1. #251
    Join Date
    Jun 2012
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    UK - Worcester
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    That was exactly my thought as well.

    Unfortunately, with the 'null register set' at I have at the moment, and a dummy ReadIO routine returning $00, the firmware 'thinks' it is running on a 4054 and 'hangs' reading I/O port $FF10.

    I will add some slightly 'less dumb' I/O routines later and see what is happening early on with the firmware 'probing'...

    Good progress though.

    I am looking to enhance my test program to checkout the other (missing) instructions and addressing mode tests - just to make sure there is nothing lurking in there that we can smoke out. Just thinking about making this into a cartridge ROM for use with Jos's generic ROM board? Perhaps add some other diagnostic features that we may need? Thoughts?

    Dave

  2. #252

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    Dave,

    I think you could add it to Jos' remake of the 4052/4054 Diagnostic ROM Pack.

    In fact - this ROM pack likely does some early microcode ROM testing.

    ftp://ftp.dreesen.ch/TEK_DRP/

    Monty

  3. #253
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    Jun 2012
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    Three more instructions added to the test - AND, ORA and EOR...

    I have added some I/O diagnostic messages to see what ports are being written to (with the value) and read from.

    I also modified the default return value read from a port that doesn't exist from $00 to $FF and that fixed it thinking it was a 4054...

    The firmware now appears to be looping reading the X-AXIS PIA for what I assume is either the DRBUSY or VPULSE (that is not generated yet).

    I will have to analyse the dump sometime to see what the firmware is up to. After scrutinising the schematics I see the 4054 has an OPTION set of links that can be switched in instead of the MAGTAPE read data. I wonder if that is the key piece of knowledge I need?

    Dave

  4. #254

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    Quote Originally Posted by jdreesen View Post
    If you buy it I can help out with key caps and digital electronics, have some spare CPU / MAS boards.
    No cover plate I am afraid....

    Jos
    Jos,

    Dave bought the 4052 and I just finished repairs and got it completely operational last night.

    The keyboard is missing the "2" key cap from the top row and the wide "0" key cap from the numeric keypad.

    The "3" key cap from the top row is broken - but the key cap is ok.

    Have you had any success with gluing broken key switches - or do you have any replacement key switches?

    Both my 4054 had broken key switches and I tried super-glue, but it didn't hold. I found a couple of the right Cherry key switches online and replaced the key switches and those keys are now fine, but I can't find anymore of those Cherry M61-0120 switches.



    I was able to type on all three of the broken key switches as the plunger broke off all three right at the bottom of the "T" part of the key switch, leaving the thicker part of the plunger above the body of the key switch - so you can still press the plunger and get the key code.
    Last edited by nikola-wan; May 9th, 2020 at 04:28 AM.

  5. #255
    Join Date
    Jun 2012
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    UK - Worcester
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    3,856

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    Monty is the Main Man !

    Dave

  6. #256
    Join Date
    Jul 2012
    Location
    Switzerland
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    124

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    Quote Originally Posted by nikola-wan View Post
    Jos,

    Dave bought the 4052
    Damn, will have to find another victim to buy my 2nd 4052....

    PM send...

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