Apple Mac Pro cutting out in use and during start-up

[pincrete]

I have a Mac Pro mid-2012 6-core, bought second hand about 6 months ago.

About 6 weeks ago it started 'cutting out' - suddenly, totally, as if there had been a power cut - and indeed it attempted to do a restart when the auto-restart was on in the energy saver prefs option. On restart the start-up ’progress bar' gets about 45% across and it then frequently cuts out again repeatedly.

It sometimes goes blank at the 45% mark, but then opens to the desktop properly. Sometimes it will then work properly for several days, sometimes only minutes or hours.

When it first started doing this, a ‘frazzled’ multi-coloured stripe appeared briefly fairly high across the start -up screen at the 45% cut out point, although it has stopped doing this,

I’ve noticed that several red leds on the logic board and cpu tray flicker briefly during start-up but maybe this is a normal part of start-up and simply something I hadn’t noticed previously.

I’ve opened up and checked that nothing is loose or not bedded in properly, nothing dirty or clogged. After doing this or after letting the Mac rest overnight, it usually works again for a while.

I’m guessing, though I know little about Mac Pros, that some basic component is ‘on the blink’ - might it be the graphics card and is there any way of testing this hypothesis?

I live on Crete, where getting a Mac repaired is extremely difficult and expensive so would be grateful for any suggestions.

 

[chscag]

Hard to pin down what it could be. However, two things come to mind:

1. Failing power supply

2. Graphics card is defective

Without replacements parts, it would be difficult to troubleshoot the Mac Pro. I know nothing at all about Crete or where you could obtain parts there.

I did find an Apple repair and parts in Greece that you could try:

iPhone, iPad, Smartphone & Laptop Repairs | iRepair

iRepair is the leader in iPhone, iPad and laptop repair with nationwide locations in Greece. Fast and guaranteed repairs in about 20 minutes.

irepair.gr

 

[pincrete]

Thanks, there is a branch of that company on Crete, which I didn't know about, but I don't know how good they are.. It's easy to get a PC fixed here, but not Macs. It might be worthwhile for me to try replacing the graphics card, since it will be possible to 'sell it on' if that is not the problem.

The 'cut-out' point during start-up is always the same, so I imagine that there is some item of hardware which it cannot load and chooses to cut-out instead.

I'm guessing that an intermittent power supply problem would not happen repeatedly at exactly the same point in the start-up each time.

The intemittent nature of the problem makes it harder for me or someone else to diagnose. Today it is behaving fine - tomorrow it might be unusable !