Need new Logic Board for Dual 1 Ghz MDD

Discussion in 'Mac Pro' started by JaimesBeam, Mar 5, 2007.

  1. JaimesBeam macrumors newbie

    Mar 5, 2007
    Franklin, ME
    I just got a Dual 1 Ghz MDD. It's a big step up from my 500 Mhz Sawtooth!

    The problem is that it (supposedly) needs a new logic board. I've been watching logic boards on ebay, but I'm not finding anything with matching part numbers. My logic board has the following numbers:

    630-4373 EEHNNW

    I guess the important numbers are the 630-* numbers. Perhaps one it the
    'as designed' rev part number, and one is the 'as manufactured' rev part number?

    I have the dual 1 Ghz processors; would they work on a 1.25 Ghz logic board? Most of the boards I see on ebay are 820-1476-A, or 820-1308-A.
    What's the difference between the 820- boards and the 630- boards?

    I don't have a complete service file for the MDD; can anyone email a copy?

    Thanks, Jim.
  2. trogdor! macrumors regular

    Mar 7, 2006
    yah, im kinda wondering the same. Ive got a dead MDD dual 1.25 that needs a new board also, but im wondering if the boards for the single processor MDD models would handle the dual just fine. The boards are really expensive so I dont want to buy a mistake. Anyone have any insight?
  3. JaimesBeam thread starter macrumors newbie

    Mar 5, 2007
    Franklin, ME
    Convert Single Processor Logic Board to Dual R676

    According to XLR8YOURMAC.COM

    "MDD Owner Guide on upgrading to Dual 1.42GHz CPU module"

    If you remove resistor R676 from a MDD single-processor logic board it will then run dual processors.

    Also look at

    "Passer le bus d'un G4 Bi 867 à 167Mhz"

    Which will change a MDD logic board from 133 Mhz to 167 Mhz.

    I haven't done this. I suspect this will *enable* the logic board to work, but
    I don't think it will guarentee that they will work. The logic board may not
    be up to the higher speed, etc.

  4. dilbert4life macrumors regular


    Jun 23, 2008
    Bolivia, according to my flag :P
    Jim is right, if you remove R676 from the underside of a 133mhz board, it will jump to 167 mhz. After that, you have to use a PC2700 ram though instead of PC2100, (that is, if you are upgrading your system from 133 to 167 and are currently using PC2100. If you are just enabling the board to run on the 167 mhz in order to replace your burnt out 167 mhz board, just use all the same components.)

    Just today, I changed my Dual 867 mhz MDD G4 @ 133 mhz to a Dual 1 Ghz MDD G4 @ 167 mhz by removing R676 from the mobo and R22 from the processor daughter board (dabo?)

    The system was unstable @ the 1.083 ghz (167 x 6.5 pll multiplier, it was left at 6.5 from the 867, which is 133 x 6.5), so i backed it down to 999.999999999 mhz (167 x 6 pll multiplier.) So far so good.

    (Daydreaming) Maybe I can get it to go to 1.25 ghz by messing with the core voltage and adding a copper heatsink from the 1.42 Dual? Ah, the possibilities.:apple:

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