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Thread: PET 2001 ROM exchange, if anyone :)

  1. #1

    Default PET 2001 ROM exchange, if anyone :)

    Hi all,
    I have started repairing my own PET 2001, after a number of other's machines.
    I've found 6 faulty 6550 (well, it would be 8, but two of them have only a broken CS line so they can live in the video ram sockets, where selects are forced true all the time) and found one faulty 6540-016 that used to live in UH4.
    No glue logic chips needed to be substituted, but interestingly enough, the leftmost 7805, that powers among other chips also UH4, failed shortly after starting the repair.
    Now, I have a spare 6540-014 (my last spare 6540 probably ever) and I would gladly exchange with a 016 if anyone happens to be in a similar situation having the wrong spare ROM.

    Best regards
    Frank IZ8DWF

  2. #2
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    Frank, Not sure if it will help you but I have two Data systems PH-001 2114 RAM adapter boards that came with my PET 2001-8 system when I bought it.
    see here:http://mikenaberezny.com/hardware/pe...4-ram-adapter/
    I have an early model 2001-8 with 6550 RAM sockets.
    MY Pet came with bad video RAM (both chips were still 6550), and since I didnt have any native ram to swap with I ended up purchasing a video RAM replacement module from Dave at Tynemouth software in the UK. I ended up buying the ROM/RAM replacement board as well. Both boards are dated 1980 and are fully populated with 2114 RAM . I realize you are in Italy and me the US, but if you are willing to pay shipping its an option. PM me and let me know.

    I was also given a later model 2001 systemboard which has the 2114 RAM sockets, its dated 1978. You can look around to see if you can find one of those perhaps. I dont want to part with it as it is my only backup board.

    I realize your post is for bad ROM, but you mention bad RAM as well.

  3. #3

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    Quote Originally Posted by VERAULT View Post
    Frank, Not sure if it will help you but I have two Data systems PH-001 2114 RAM adapter boards that came with my PET 2001-8 system when I bought it.
    see here:http://mikenaberezny.com/hardware/pe...4-ram-adapter/
    I have an early model 2001-8 with 6550 RAM sockets.
    MY Pet came with bad video RAM (both chips were still 6550), and since I didnt have any native ram to swap with I ended up purchasing a video RAM replacement module from Dave at Tynemouth software in the UK. I ended up buying the ROM/RAM replacement board as well. Both boards are dated 1980 and are fully populated with 2114 RAM . I realize you are in Italy and me the US, but if you are willing to pay shipping its an option. PM me and let me know.

    I was also given a later model 2001 systemboard which has the 2114 RAM sockets, its dated 1978. You can look around to see if you can find one of those perhaps. I dont want to part with it as it is my only backup board.

    I realize your post is for bad ROM, but you mention bad RAM as well.
    Hi,
    I have designed my own 6550 and 6540 adapters, I could use 2114 SRAMs to replace the 6550 and 2716 EPROMs to replace the 6540.
    I have also designed my own RAM/ROM replacement daughterboard so my 2001 can run basic 4 with 32Kbytes of RAM via the daugherboard. I wanted to have a complete basic 2 romset if possible, since it's only one missing ROM and I happen to still have another good 6540, albeit different from the one I'm missing.
    Search on youtube: PET 2001 iz8dwf
    and you'll see those adapters and replacement board in action.

    Frank IZ8DWF

  4. #4

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    Turns out that my actual spare 6540 is a 012. I indeed have a 014 too but it's a bad one.
    Sorry for the mistake.

    BTW here's the video of the first part of the repairing of my 2001:

    https://www.youtube.com/watch?v=Hgz1GqeprKE

  5. #5
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    Quote Originally Posted by iz8dwf View Post
    Hi,
    ... I wanted to have a complete basic 2 romset if possible, since it's only one missing ROM and I happen to still have another good 6540, albeit different from the one I'm missing.
    Hi Frank,

    Aren't these BASIC1 "Original" ROMs? Or do you consider the BASIC1 patch as a separate version?
    BASIC2 usually refers to the "Upgrade" ROMs, although they are sometimes also called BASIC3.

    FWIW, I do have some spare BASIC2 ROMs but am looking for a 6540-024.

    http://www.6502.org/users/andre/petindex/roms.html

  6. #6

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    Quote Originally Posted by MikeS View Post
    Hi Frank,

    Aren't these BASIC1 "Original" ROMs? Or do you consider the BASIC1 patch as a separate version?
    BASIC2 usually refers to the "Upgrade" ROMs, although they are sometimes also called BASIC3.

    FWIW, I do have some spare BASIC2 ROMs but am looking for a 6540-024.

    http://www.6502.org/users/andre/petindex/roms.html
    It's not "me", it's more CBM itself that has made the "naming", having called its last revision Basic4
    Basic1 is the original romset with 6540-011 in UH1 (901439-01), quite rare, I've never seen one myself, but they must exist in the wild.
    Basic2 is also the "original" romset but with 6540-019 in UH1 (901439-09), this is what we find in most PET 2001. We could refer to this as "patched Basic1", but I prefer Basic2.
    Then we have the finally fixed (IEEE works!) Basic3 that was the stock on 2001N (aka 30xx) PETs, and the Basic4 that we find in 40xx PETs (both 2001N and universal boards).
    I've had a private message from a member that has the 6540-016, I still don't know if he's interested in my 012 though.

    Frank

  7. #7
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    I suspect this may be a Europe vs. North America issue; over here BASIC 2 almost always refers to the ### upgrade BASIC normally in 2001N models and although they're common in Europe you won't find many of the (identical) 3xxx versions over here.

    See:
    https://www.c64-wiki.com/wiki/PET_2001
    https://en.wikipedia.org/wiki/Commodore_BASIC

    As you say, BASIC1 and what you call BASIC2 use the identical same 6 ROMs with the exception of the Cxxx patch ROM.

    There is an official document somewhere; I'll try to find it and see what Commodore thought.

    And of course a 4032 can be a 9" version (essentially a 2001N/3032 with BASIC4) or the new 12" FAT40 with the CRTC...

    Potayto, potahto, as long as there's no confusion...
    Last edited by MikeS; November 5th, 2018 at 04:10 PM.

  8. #8
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    FWIW, here's the official list of BASIC versions (from the BASIC4 source):

    https://www.davidviner.com/cbm9.html...2B+Source+Code

    " ...while there was controversy over the naming of the various different PET versions of BASIC prior to 4.0, this source is probably puts that to rest. The arguments over whether or not there was ever a version 3.0 can be seen here - yes, there was - but, as far as I know, it was never released in ROM. 1.0 was the original version for the Old ROM PET, 2.0 was the debugged version, 3.0 added the faster string garbage collection routines and got combined into 4.0..."

    And from the BASIC5 source:

    ;VERSION 1 - AUGUST 1977
    ; ORIGINAL MICROSOFT RELEASE
    ;VERSION 2 - AUGUST 1978
    ; FIXED MANY BUGS SOME ARE:
    ; 1) ARRAYS LIMITED TO 255
    ; 2) NON-INTERRUPTABLE CODE
    ; 3) GARBAGE COLLECT STRINGS
    ;VERSION 3 - MAY 1979
    ; FASTER GARBAGE COLLECT
    ;VERSION 4 - JULY 1979
    ; 1) EXPAND RESERVED WORDS
    ; 2) ADD DISK COMMANDS
    ; 3) ADD DISK STATUS VARS.
    ;VERSION 5 - 26 SEPT 1979
    ; 1) MERGE WITH BASIC-AID
    ; 2) ADD DECIMAL MATH PACKAGE

  9. #9

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    Quote Originally Posted by MikeS View Post
    FWIW, here's the official list of BASIC versions (from the BASIC4 source):

    https://www.davidviner.com/cbm9.html...2B+Source+Code

    " ...while there was controversy over the naming of the various different PET versions of BASIC prior to 4.0, this source is probably puts that to rest. The arguments over whether or not there was ever a version 3.0 can be seen here - yes, there was - but, as far as I know, it was never released in ROM. 1.0 was the original version for the Old ROM PET, 2.0 was the debugged version, 3.0 added the faster string garbage collection routines and got combined into 4.0..."

    And from the BASIC5 source:

    ;VERSION 1 - AUGUST 1977
    ; ORIGINAL MICROSOFT RELEASE
    ;VERSION 2 - AUGUST 1978
    ; FIXED MANY BUGS SOME ARE:
    ; 1) ARRAYS LIMITED TO 255
    ; 2) NON-INTERRUPTABLE CODE
    ; 3) GARBAGE COLLECT STRINGS
    ;VERSION 3 - MAY 1979
    ; FASTER GARBAGE COLLECT
    ;VERSION 4 - JULY 1979
    ; 1) EXPAND RESERVED WORDS
    ; 2) ADD DISK COMMANDS
    ; 3) ADD DISK STATUS VARS.
    ;VERSION 5 - 26 SEPT 1979
    ; 1) MERGE WITH BASIC-AID
    ; 2) ADD DECIMAL MATH PACKAGE
    So, the patched Basic1 here isn't even mentioned?
    We know there're 4 different revisions of Basic for the PETs, we can call them as we prefer I guess
    First, Second, Third and Fourth would even do it for me, as long as we agree on what we are referring to.
    Frank

  10. #10
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    Quote Originally Posted by iz8dwf View Post
    So, the patched Basic1 here isn't even mentioned?
    We know there're 4 different revisions of Basic for the PETs, we can call them as we prefer I guess
    First, Second, Third and Fourth would even do it for me, as long as we agree on what we are referring to.
    Frank
    Depends on what you call a PET; there is a BASIC5... If you're going to call an 8032 a PET then why not a CBM-II...

    I think most people assume that a BASIC1 set has been patched; that patch doesn't really make a new version.

    So, there's the 'Original' BASIC, the 'Upgrade' and BASIC4, each with a different sign-on.

    But you're right, as long as we agree, which is why I piped up in the first place; there are obviously some different opinions whether BASIC2 is a patched BASIC1 or the same as 'BASIC3' and I thought it worth mentioning, although in your original post the part numbers did avoid any confusion.

    Commodore was never known for consistency...

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