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Thread: Troubleshooting a QuadRAM QuadBoard

  1. #11
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    Bank 0 only (16K)
    ------------------

    BIOS = 04/24/81

    SW1: 3=ON, 4=ON
    SW2: 1=ON, 2=ON, 3=ON, 4=ON

    With a video card being the only card plugged in, at power-on, there was a 601 error, then after a while, Cassette BASIC started. BASIC (version C1.00) displayed "12252 Bytes free" .

    Powered off. I then added a floppy controller and 360K drive. No DOS boot diskette in the drive. Powered on. The floppy drive was accessed, then after a while, Cassette BASIC started.

    Powered off. I then put a DOS boot floppy, of IBM DOS version 3.10, into the drive. Powered on. The floppy drive was accessed, then "PARITY CHECK 1" appeared. On the floppy drive, the access LED stayed on and the spindle continued to turn, even so after a few minutes.

    Presumably, the PARITY CHECK 1 was an unfriendly result of IBM DOS 3.10 not being able to cope with only 16K of RAM.


    Banks 0 and 1 only (32K)
    -----------------------

    BIOS = 04/24/81

    SW1: 3=OFF, 4=ON
    SW2: 1=ON, 2=ON, 3=ON, 4=ON

    With a video card being the only card plugged in, at power-on, there was a 601 error, then after a while, Cassette BASIC started. BASIC (version C1.00) displayed "28638 Bytes free" .

    Powered off. I then added a floppy controller and 360K drive. No DOS boot diskette in the drive. Powered on. The floppy drive was accessed, then after a while, Cassette BASIC started.

    Powered off. I then put a DOS boot floppy, of IBM DOS version 3.10, into the drive. Powered on. The floppy drive was accessed, then "PARITY CHECK 1" appeared. On the floppy drive, the access LED stayed on and the spindle continued to turn, even so after a few minutes.

    Presumably, the PARITY CHECK 1 was an unfriendly result of IBM DOS 3.10 not being able to cope with only 32K of RAM.


    Banks 0 and 1 and 2 only (48K)
    -------------------------------

    BIOS = 04/24/81

    SW1: 3=ON, 4=OFF
    SW2: 1=ON, 2=ON, 3=ON, 4=ON

    With a video card being the only card plugged in, at power-on, there was a 601 error, then after a while, Cassette BASIC started. BASIC (version C1.00) displayed "45020 Bytes free" .

    Powered off. I then added a floppy controller and 360K drive. No DOS boot diskette in the drive. Powered on. The floppy drive was accessed, then after a while, Cassette BASIC started.

    Powered off. I then put a DOS boot floppy, of IBM DOS version 3.10, into the drive. Powered on. The floppy drive was accessed, then "PARITY CHECK 1" appeared. On the floppy drive, the access LED stayed on and the spindle continued to turn, even so after a few minutes.

    Presumably, the PARITY CHECK 1 was an unfriendly result of IBM DOS 3.10 not being able to cope with only 48K of RAM.


    All banks (64K)
    -------------------------------

    BIOS = 04/24/81

    SW1: 3=OFF, 4=OFF
    SW2: 1=ON, 2=ON, 3=ON, 4=ON

    With a video card being the only card plugged in, at power-on, there was a 601 error, then after a while, Cassette BASIC started. BASIC (version C1.00) displayed "61404 Bytes free" .

    Powered off. I then added a floppy controller and 360K drive. No DOS boot diskette in the drive. Powered on. The floppy drive was accessed, then after a while, Cassette BASIC started.

    Powered off. I then put a DOS boot floppy, of IBM DOS version 3.10, into the drive. Powered on. DOS version 3.10 booted to a DOS prompt.

  2. #12
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    Quote Originally Posted by modem7 View Post
    IBM DOS 3.10 is the earliest version of which I have a boot floppy. I will see if I can create boot floppies of earlier DOS versions.
    IBM DOS 1.00

    Attempt to boot using an IBM DOS 1.00 boot floppy:

    M/B configured for 16K = DOS booted successfully
    M/B configured for 32K = DOS booted successfully
    M/B configured for 48K = DOS booted successfully
    M/B configured for 64K = DOS booted successfully


    IBM DOS 2.10

    Attempt to boot using an IBM DOS 2.10 boot floppy:

    M/B configured for 16K = 'PARITY CHECK 1' on-screen, plus floppy drive access LED on continuously, plus floppy drive spindle turning continuously.
    M/B configured for 32K = Nothing on-screen except underline cursor. Floppy drive access LED on continuously, plus floppy drive spindle turning continuously.
    M/B configured for 48K = DOS booted successfully
    M/B configured for 64K = DOS booted successfully

  3. #13
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    I am summarising the 'not enough RAM for DOS' information at [here].

  4. #14

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    Oddly, I didn't have a DOS disk in when the error first appeared. I don't think it has anything to do with DOS.

  5. #15
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    Quote Originally Posted by joelgraff View Post
    Oddly, I didn't have a DOS disk in when the error first appeared. I don't think it has anything to do with DOS.
    'PARITY CHECK 1' ?

    I see that you have not written about 'PARITY CHECK 2'. PARITY CHECK 2 is certainly expected because the 201 errors that you have written of to date, point to the Quadboard card. The '2' indicates an expansion card source.

    If indeed PARITY CHECK 1 (motherboard is source of parity error), if you adequately detail the situation in which that occurs, I will try to replicate it here.

    Going back over the posts, I see that I have not answered your primary query which was about the 201 errors that point to the Quadboard.
    Assuming that you have not made progress on that:
    - First, re-seat all of the RAM chips on the Quadboard.
    - Inform us of exactly which version of Quadboard you have, so that banks and bits can be identified. A pointer to a photo would be good.
    - Inform us of the 201 errors that are still occurring.

    The combined facts of multiple 201 errors, and a BASIC chip that has a "rusted through leg" suggests a machine that has endured a 'hostile' environment. Hopefully, multiple re-seating of the RAM chips on the Quadboard will 'do the trick'.

  6. #16

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    Quote Originally Posted by modem7 View Post
    'PARITY CHECK 1' ?

    I see that you have not written about 'PARITY CHECK 2'. PARITY CHECK 2 is certainly expected because the 201 errors that you have written of to date, point to the Quadboard card. The '2' indicates an expansion card source.

    If indeed PARITY CHECK 1 (motherboard is source of parity error), if you adequately detail the situation in which that occurs, I will try to replicate it here.

    Going back over the posts, I see that I have not answered your primary query which was about the 201 errors that point to the Quadboard.
    Assuming that you have not made progress on that:
    - First, re-seat all of the RAM chips on the Quadboard.
    - Inform us of exactly which version of Quadboard you have, so that banks and bits can be identified. A pointer to a photo would be good.
    - Inform us of the 201 errors that are still occurring.

    The combined facts of multiple 201 errors, and a BASIC chip that has a "rusted through leg" suggests a machine that has endured a 'hostile' environment. Hopefully, multiple re-seating of the RAM chips on the Quadboard will 'do the trick'.
    I've used two different Quadboards (both 256K) in this machine with the same error. Both work fine in my working 5150 Rev A.

    The bytecode tells me it's seeing the error in the 64K bank (x10), but only when the QuadBoard is installed. I've also seen an error for x3008, which puts it in the 192K bank, but I don't remember what I had done that caused that to appear at the moment.

    To the point, though, I don't think the QuadBoards are the issue, as both work without generating errors on another machine. I'll re-run those tests to be sure, though.

    Otherwise, I'm waiting on a replacement ROM and socket for BASIC at the moment. Figure I should at least clear that issue first.

  7. #17
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    Quote Originally Posted by joelgraff View Post
    I've used two different Quadboards (both 256K) in this machine with the same error. Both work fine in my working 5150 Rev A.
    The bytecode tells me it's seeing the error in the 64K bank (x10), but only when the QuadBoard is installed.
    Because of your earlier "102B 201, and 10AA 201", I'm sure that you meant something like '10xx', i.e. for your 16KB-64KB type motherboard, the '10' points to the first bank on the Quadboard.

    Given the 'hostile' environment that the machine has suffered, an environment that rusted away the leg on a chip, I wonder if the metal contacts in your motherboard's ISA slots are badly affected in some way. How confident are you that the contacts are functional ?

  8. #18
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    BTW. This is something that you can try if you want: Using Casette BASIC to write-then-read test bytes to the first bank of RAM on the Quadboard.

    Presently, you only have 64 KB of RAM (maximum motherboard RAM), which is hardly anything for running RAM diagnostics. As soon as you add the Quadboard, and set SW2 accordingly, a reboot results in a 201 10xx error (the '10' pointing to the Quadboard's first bank of RAM), then the screen clears, then a 'PARITY CHECK 2' error, then the 5150 halts.

    So, add the Quadboard, but leave SW2 set for 64 KB total conventional memory. Your 5150 will then start, sucessfully test the 64 KB of motherboard RAM, then continue to Cassette BASIC. The Quadboard's RAM, starting at address 64K, will be present (although the POST/BIOS are unaware of it).

    Below, we will first disable the motherboard from reacting to a RAM parity error.
    We then write 0 to the first byte of the Quadboard's first bank of RAM, then read the byte back, expecting 0.
    We then write 255 (all one's) to the first byte of the Quadboard's first bank of RAM, then read the byte back, expecting 255.

    In Cassette BASIC, enter the following commands:

    out &hA0,inp(&hA0) and 127
    def seg = &h1000
    poke 0,0
    print peek(0)


    You should see 0.

    poke 0,255
    print peek(0)


    You should see 255.

  9. #19

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    Actually, I tried switching the mobo to 64K only with the Quadboard in early on. It still game me an error. If I pull the Quadbaord, it boots fine, again, swtiched to 64K max. It's part of why the problem seems so confusing - that suggested a short to me in the quadboard that was backfeeding the system, but again, it ran fine in my working 5150 A. I tried a different slot with the same effect.

    Anyway, I need to replace the BASIC ROM first, then maybe pull and reseat the chips just as an opportunity to inspect things. The rusted leg tells me I really need to tear this thing down and give it a good cleaning anyway.

    That said, I still suspect there may be an issue with the Quadboard - I noticed something that made me think that, but it escapes my memory at the moment. Once I get the BASIC ROM replaced and give the board a good cleaning, I'm sure I'll be back.

    @modem7 - thanks for the tips. You've been a dogged troubleshooter. I appreciate it!

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