Mac Pro 3.1 power light blinks - no video, no chime

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Level 1

4 points

Mac Pro 3.1 power light blinks - no video, no chime

Hey There!

I've already posted that on another forum, but it didn't change something at all, so I guess I need your help.

I bought a 3,1 Mac Pro with 1 x 2,8 Xeon Quad-Core processor, 10 gb of RAM and a native ATI Radeon HD 2600 XT.

Everything seemed to be alright, it was working, but then I tried to replace thermal paste and accidentally dropped a screw on the motherboard surface, and USB ports stopped working at all.

Then I decided to replace motherboard, bought it from the secondary market, brought that all together and ran into a problem: when I try to boot it, fans go as usual, but there is no video or chime, only white led blinking permanently.

I searched for the problem solution, followed some recommendations, but they had no effect at all.

What I tried:

- RAM re-seating

- GPU re-seating

- CPU re-seating

- booting without everything

- 3V battery replacing

- SMC reset

- NVRAM reset (keyboard seems to be not working, so idk did it help or not)

I also pressed a DIAG_LED button, here's the results:

- STBY (LED 2) come on with the yellow light

- PWRG (LED 8) come on with the green light

According to LED 8 I guess it's not a PSU issue. And according to previous actions I guess it's not a GPU or RAM issue.

So what should I do? Any ideas? Everything will be respected!

Earlier Mac models

Posted on Sep 20, 2024 1:06 PM

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Answer 1

Sep 21, 2024 11:36 AM in response to okcomput3r

The chime is created is software when your Mac passes the Power-on self-test, and not otherwise.

The usual thing with the power light is that it blinks a "help me" message before there is any other way to get the message out. So for example, three blinks means 'not enough Working RAM to start up.'

if your symptom seems to be one blink, then repeating, that is supposed to mean that the ROM checksum failed, (and therefore your board and its on-board ROM is bad) and you can not proceed because results may be wildly unpredictable. There is no way to know what will happen if you did proceed.

I am not sure whether that is the same or different from incessant blinking.

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Answer 2

Sep 21, 2024 3:41 PM in response to okcomput3r

For ordinary people, the suggestion would be to replace the mainboard, and get one that includes a GOOD working ROM.

For you, you bought a board and tried to use it. Presuming your previous board allowed most items to work, and you DID get a chime and were able to proceed, you appear to have installed a [now] Known-Bad component and made backward progress.

The issues seem to follow the installation of the new board.

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Answer 3

okcomput3r Author

Level 1

4 points

Sep 21, 2024 2:34 PM in response to Grant Bennet-Alder

Thanks for your answer! So is it a ROM issue? And what can I do with that?

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