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  • PC 730/750 "secret" 33 MHz base clock setting

    From Christian Holzapfel@21:1/5 to All on Fri Nov 24 01:03:01 2023
    IBM states:

    J26/J27 = 2-3/2-3 => 50 MHz
    J26/J27 = 2-3/1-2 => 60 MHz
    J26/J27 = 1-2/1-2 => 66 MHz

    By setting the fourth option

    J26/J27 = 1-2/2-3

    the system runs at a 33 MHz CPU base clock.
    Darn, was hoping for 75...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Louis Ohland@21:1/5 to Christian Holzapfel on Fri Nov 24 06:17:23 2023
    https://www.ardent-tool.com/PC750/#Jumpers

    Bus/CPU Speed MHz Setting

    Is there a reason why the board component outline follows the arcane IBM location diagram, instead of the [sl]eazier to understand method used on
    the Ardent Tool?

    Example:
    2 (J15) Modem Ring Detect connector

    How about:
    J15 Modem Ring Detect connector

    Christian Holzapfel wrote:
    IBM states:

    J26/J27 = 2-3/2-3 => 50 MHz
    J26/J27 = 2-3/1-2 => 60 MHz
    J26/J27 = 1-2/1-2 => 66 MHz

    By setting the fourth option

    J26/J27 = 1-2/2-3

    the system runs at a 33 MHz CPU base clock.
    Darn, was hoping for 75...


    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tomas Slavotinek@21:1/5 to Louis Ohland on Wed Nov 29 22:20:19 2023
    On 24.11.2023 13:17, Louis Ohland wrote:
    https://www.ardent-tool.com/PC750/#Jumpers

    Is there a reason why the board component outline follows the arcane IBM location diagram, instead of the [sl]eazier to understand method used on
    the Ardent Tool?

    Well, it's simple. Nobody bothered to make a proper outline...

    But I have a PC750 meow, so that's gonna change soon(tm).

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tomas Slavotinek@21:1/5 to Christian Holzapfel on Wed Nov 29 22:17:48 2023
    On 24.11.2023 10:03, Christian Holzapfel wrote:
    IBM states:

    J26/J27 = 2-3/2-3 => 50 MHz
    J26/J27 = 2-3/1-2 => 60 MHz
    J26/J27 = 1-2/1-2 => 66 MHz

    By setting the fourth option

    J26/J27 = 1-2/2-3

    the system runs at a 33 MHz CPU base clock.
    Darn, was hoping for 75...

    Thanks! Table updated:
    https://ardent-tool.com/PC750/#Jumpers

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