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The 2013 revamp of the desktop Mac series known as the Mac Pro.

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'Lights Up' But never shows video & shuts down: Likeliest issues?

Powers on, (the input panel lights up and the fan spins), but, never shows video … and eventually just shuts down.

(I actually attempted resetting the PRAM but was unable to get it to do so, thus, never got a chime out of it … but I bought it from a good customer ‘non-operative’ who’s at LEAST savvy enough to attempt swapping memory modules.)

I’ve disassembled it, and actually have replacement CPUs (and RAM of course) I could swap out to check what the issue is; the only thing I don’t have is a GPU.

Though, I’m curious, would this unit work with ONE GPU..? If so, I could disable each GPU while using the other to see if that’s the issue ….

Or, are there other ‘more likely’ candidate issues ..?

Thanks

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The GPU’s are not the same! One is the dominant the other only becomes active when the driven to do so. So you can’t alter things.

So when did you encounter the issue before or after you upgrade the CPU?

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Thanks for the reply; the CPU’s actually OEM. I received the unit not functioning.

I took it apart to check for loose components or bad cables, etc.

(I’ve done a bunch of these).

With Macs I'd assume it’s a GPU issue & recall MP6,1 having a QP (over I'm sure).

Without other advice, my plans are:

Boot in single user / verbose to see if there’s any useful info.

Without buying anything I can at least replace the CPU and rule it out.

If neither of the above yield results

Though I’ve inspected both GPU cables & main cable (no bent pins)

I can order replacement cables from someone with a return policy.

If all of those attempts fail

I’ll confirm if it’s the GPU or CPU / main board …

When next I have a KG MP6,1 in stock.

(Btw, great feature how the arrows move the cursor all the way to the top instead of moving up or down one)

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@trumanhw - I would snag the service manual which yo can find online and review the onboard diagnostic LED's to see what they tell you.

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@danj

I have the board layout ... I'm just not familiar with the behavior:

Light turns on when plugged in or, after it turns off by pressing the power button...

But I don't think the FAN even spins up.

Can't reset the PRAM, etc.,

Verbose obviously didn't work

No chime -- but it lights up the ... led over the ports, etc.

But that's about the only indices of anything happening.

Ideas ...?

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@trumanhw - You also need the service manual

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trumanhw will be eternally grateful.
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