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pdimitrov Author

Level 1

4 points

Mac Pro 3.1 early .2008 red light on risers question

Recently I got a Mac Pro 3.1 early 2008 logic board 630-7997.

Hope to get it operational but so far there are 2 questions I am unable to get answers.

Memory risers- in the top memory riser no mater how many DIMM‘s are inserted (even none attached to the logic board) all 4 red lights are on. On the bottom memory riser - no meter how many DIMM’ s are inserted allays only 2 red lights are on- the lights are steady, not blinking.

Is this is an indication for faulty memory risers?

2: GPU- when inserted nviidea 880 ( originally shaped with this Mac) and pressed on power button then chime is emitted and question mark is displayed. The problem is that - all screen is filled with vertical strips and this make me think that the GPU is faulty . However, when different card is inserted ( AT Radeon 5770 or Gigabyte GT 1050) the computer shuts down automatically .

Is this is an indication that Radeon 5770 / GTX1050 have high power consumption or cards are faulty?

3, after system displayed question mark the computer’s fans run only in high speed. Is this is normal behaviour when no OS is installed?

thanks for you help.

Posted on May 3, 2024 3:14 AM

19 replies

May 15, 2024 5:58 PM in response to pdimitrov

Diagnostics catch GROSS problems. Most of the time because of constraints of time and limited number and types of tests, they come up empty-handed.

When you actually manage to catch an issue with a diagnostic, you count your blessings. There is NO NEED to corroborate or get a second opinion. You caught it making a mistake.