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  • Auction: FALSCH! Vintage IBM Motherboard FRU- 33F8415 System Board Inte

    From Louis Ohland@21:1/5 to All on Fri Jan 13 15:45:38 2023
    https://www.ebay.com/itm/165836172114

    BIN / MAO

    Not an actual Axx systemboard, only three 32-bit slots and only one
    16-bit video slot.

    It does have a 386DX-25, but the systemboard is not a 25MHz model. :(

    --- SoupGate-Win32 v1.05
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  • From Tomas Slavotinek@21:1/5 to Louis Ohland on Fri Jan 13 23:50:21 2023
    On 13.01.2023 22:45, Louis Ohland wrote:
    https://www.ebay.com/itm/165836172114

    BIN / MAO

    Not an actual Axx systemboard, only three 32-bit slots and only one
    16-bit video slot.

    It does have a 386DX-25, but the systemboard is not a 25MHz model. :(

    A 40 MHz oscillator - yeah, just a regular 20 MHz T2 planar.

    Yet another FRU P/N though... what a mess.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tomas Slavotinek@21:1/5 to IBMMuseum on Sun Jan 15 17:58:51 2023
    On 15.01.2023 17:23, IBMMuseum wrote:
    I just looked harder at my 'Type 2' Model 80 planar pictured at the 'Ardent-Tool'; It has a bunch of bodge-wires - and a 386DX-16MHz CPU with a 32MHz crystal on the planar! Now I need to look over my other T2s - That one has been 16MHz the whole time!

    Maybe that explains an FRU difference...

    The CPU clock (among other signals) is derived from the 40 MHz
    oscillator U110. The 32 MHz oscillator U159 is used for the FPU (and
    other things).

    So, unless the board can be "jumpered" differently to change the clock
    source, I'd say somebody installed an incorrect CPU. Can you measure the
    clock frequency at the CPU CLK pin (or buzz the path out with the help
    of the schematic)?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From IBMMuseum@21:1/5 to All on Sun Jan 15 08:23:00 2023
    Not an actual Axx systemboard, only three 32-bit slots and only one
    16-bit video slot.

    It does have a 386DX-25, but the systemboard is not a 25MHz model. :(
    A 40 MHz oscillator - yeah, just a regular 20 MHz T2 planar.

    Yet another FRU P/N though... what a mess.

    I just looked harder at my 'Type 2' Model 80 planar pictured at the 'Ardent-Tool'; It has a bunch of bodge-wires - and a 386DX-16MHz CPU with a 32MHz crystal on the planar! Now I need to look over my other T2s - That one has been 16MHz the whole time!

    Maybe that explains an FRU difference...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tomas Slavotinek@21:1/5 to Tomas Slavotinek on Sun Jan 15 18:11:25 2023
    On 15.01.2023 17:58, Tomas Slavotinek wrote:
    On 15.01.2023 17:23, IBMMuseum wrote:
    I just looked harder at my 'Type 2' Model 80 planar pictured at the
    'Ardent-Tool'; It has a bunch of bodge-wires - and a 386DX-16MHz CPU
    with a 32MHz crystal on the planar! Now I need to look over my other
    T2s - That one has been 16MHz the whole time!

    Maybe that explains an FRU difference...

    The CPU clock (among other signals) is derived from the 40 MHz
    oscillator U110. The 32 MHz oscillator U159 is used for the FPU (and
    other things).

    So, unless the board can be "jumpered" differently to change the clock source, I'd say somebody installed an incorrect CPU. Can you measure the clock frequency at the CPU CLK pin (or buzz the path out with the help
    of the schematic)?

    E1 and E2 above the 32 MHz oscillator are dealing with the clock, but
    only allow two configurations - synchronous where the FPU uses the 40
    MHz CPU*2 clock, or asynchronous where it has its own 32 MHz source (if
    the schematic is correct). I don't see a "jumper" in the CPU*2 path for
    the 386.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From IBMMuseum@21:1/5 to All on Sun Jan 15 09:37:08 2023
    The CPU clock (among other signals) is derived from the 40 MHz
    oscillator U110. The 32 MHz oscillator U159 is used for the FPU (and
    other things).

    So, unless the board can be "jumpered" differently to change the clock source, I'd say somebody installed an incorrect CPU. Can you measure the clock frequency at the CPU CLK pin (or buzz the path out with the help
    of the schematic)?
    E1 and E2 above the 32 MHz oscillator are dealing with the clock, but
    only allow two configurations - synchronous where the FPU uses the 40
    MHz CPU*2 clock, or asynchronous where it has its own 32 MHz source (if
    the schematic is correct). I don't see a "jumper" in the CPU*2 path for
    the 386.

    I can't remember enough history - but I think I received it as a disembodied planar (and no memory of who put in the CPU and FPU). I may have been testing a CPU 'Reset Signature' (but that doesn't explain the 16MHz FPU). On another tangent, we haven't
    traced what the solder-pad header (differing in size) is on the Type 1 and Type 2 planars, and the 2-pin jumper on the Type 2.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tomas Slavotinek@21:1/5 to IBMMuseum on Sun Jan 15 18:47:09 2023
    On 15.01.2023 18:37, IBMMuseum wrote:
    On another tangent, we haven't traced what the solder-pad header (differing in size) is on the Type 1 and Type 2 planars, and the 2-pin jumper on the Type 2.

    Yeah, will have to do some probing to figure that out. The rows of
    solder pads might be just for testing, but the E3 jumper is actually populated...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From richard smice@21:1/5 to [email protected] on Sun Jan 15 14:40:57 2023
    On Sunday, January 15, 2023 at 12:47:12 PM UTC-5, [email protected] wrote:
    On 15.01.2023 18:37, IBMMuseum wrote:
    On another tangent, we haven't traced what the solder-pad header (differing in size) is on the Type 1 and Type 2 planars, and the 2-pin jumper on the Type 2.
    Yeah, will have to do some probing to figure that out. The rows of
    solder pads might be just for testing, but the E3 jumper is actually populated...


    At one time ; many years back, I had picked up a over 100 of these huge heavy boxes, mostly early versions of the 386 mod 80's from back then; National Grid from upstate NY,, In Syracuse, Most of them had severe hard drive damage in the old aluminum
    cased seagate hard drives that were installed in them, St-506's or 225's or something.
    huge media failures from spin rite..... some internal shredding platens...lots of the floppy drives had the little foam rubbers from on top of the heads floating around inside them.
    The sound barrier foam on from the covers falling in on them, making a goey mess..no locks and keys.. I barely got my money back selling them for scrap or parts..
    Lots of mother board failures . I didn't spend a lot of time with them.. I still have many of them in the warehouse.. I still use them for shelf uprights on 2x8 planks
    they are very stable with the feet spread out... At onetime I had thought about using them; Filled with concrete, for a retaining wall...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)