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MP 1,1-5,1 Mac Pro Dead

I

ironmanny1

macrumors member
Original poster
Oct 28, 2018
67
28
Hey Guys,

Power Supply or Back Plane? What do yo guys think?

I've converted my Trusty Mac Pro 4,1 -> 5,1 to a sim rig running windows. I have a 2080 ti with a Pixlas Mod. I was burning rubber, smoke everywhere then the computer shutoff. No physical smoke =)

So, now it doesn't turn on anymore. Just dead. Physically unplugged power off for about 10 mins. plugged it in, I saw a red flash for a brief second. Pressing the power button does nothing.

I'm thinking either a dead power supply or back plane. I'm going to strip the computer to a bare minimum and see what happens.

Worst case. Just go on to eBay and buy some parts right.
 
Reach out to @tsialex - or search for his posts. Good advice on the steps to debug what part or parts are bad.

Definitely want to strip it down to the minimum. It is beneficial if you have another known working MacPro to test parts one at a time.
 
Since at this moment you still don't know what is/are defective and will need to test/diagnose your dead Mac Pro, buying parts piece meal is probably more expensive than getting a cheap working early-2009.

So, take a look at the price of a working one before the eBay buying starts.
 
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Thank you, It appears to be the back plane. I've grabbed another power supply from a friend and it doesn't work in the dead Mac Pro. I took my dual CPU tray and put it in my buddy's computer and it works just fine.
 
Ordered a backplane on eBay and replaced the broken one. Got a bootrom reconstruction from tsialex. System is all good now, it is up and running. Time to burn some more rubber. Thanks guys.
 
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After an aborted attempt to retrofit external WiFi antennas ( cable plugs too small to fit reliably) I ended up with howling fans. smcFanControl showed them at 800/600 RPM with boost fans A&B at 0. Speed could not be controlled. Pulling the system apart it showed a couple of CPU tray pins bent beyond repair as the likely cause.

Who is a reliable backplane source on eBay?
 
haralds said:
After an aborted attempt to retrofit external WiFi antennas ( cable plugs too small to fit reliably) I ended up with howling fans. smcFanControl showed them at 800/600 RPM with boost fans A&B at 0. Speed could not be controlled. Pulling the system apart it showed a couple of CPU tray pins bent beyond repair as the likely cause.

Who is a reliable backplane source on eBay?
Click to expand...
I ended up buying the cheapest board available. Cost me about $50 USD after shipping and tax. The problem is that the board was already crossed flash from 4,1 to 5,1. tsialex did a reconstruction service for me.
 
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ironmanny1 said:
I ended up buying the cheapest board available. Cost me about $50 USD after shipping and tax. The problem is that the board was already crossed flash from 4,1 to 5,1. tsialex did a reconstruction service for me.
Click to expand...
im having the very same issue, and it started last night. i have two 5,1, one i use daily and one is a backup, i stored it in a damp closet for about 2 months and when i tried to turn it on, nothing happened. luckily i have the other, so i swapped power supply but still nothing, swapped trays and all is fine there, so in my mind the only logical option would be a used backplane off ebay.
 
MrScratchHook said:
im having the very same issue, and it started last night. i have two 5,1, one i use daily and one is a backup, i stored it in a damp closet for about 2 months and when i tried to turn it on, nothing happened. luckily i have the other, so i swapped power supply but still nothing, swapped trays and all is fine there, so in my mind the only logical option would be a used backplane off ebay.
Click to expand...
Some people have found that the dust and thermal pads create a sticky, dusty substance that is conductive. With careful cleaning with isopropyl alcohol (very pure) the residue can be cleaned and perhaps the board saved.

Before buying parts you should test all the parts on the non working cMP in the working cMP to isolate what is happening. Also do a careful inspection of the backplane.
 
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tsialex said:
Since at this moment you still don't know what is/are defective and will need to test/diagnose your dead Mac Pro, buying parts piece meal is probably more expensive than getting a cheap working early-2009.

So, take a look at the price of a working one before the eBay buying starts.
Click to expand...
Hi tsialex could you hit me with a link of how to read and understand the diagnostic lights. My 2010 5,1, dual 3.46 is not turning on after being stored in a damp/hot closet for 2 months. i've swapped power supplies with my 2012 and that's not the problem, i've swapped cpu trays, thats not the problem, upon plugging the power cord i see two red lights flicker in the diagnostics section, they turn off one second later, and those two say cpu A and cpu B. upon pressing power button nothing happens. After pressing the white diag button inside the mac, the yellow stndby light comes on and obviously goes off once i let the button go. i havent tried the battery yet, but im doubtful if it will fix it, but im starting to accept that its the backplane, which may need replacing, but i'd like to get a better understanding of the diagnostic lights. thanks for your help
 
sfalatko said:
Some people have found that the dust and thermal pads create a sticky, dusty substance that is conductive. With careful cleaning with isopropyl alcohol (very pure) the residue can be cleaned and perhaps the board saved.

Before buying parts you should test all the parts on the non working cMP in the working cMP to isolate what is happening. Also do a careful inspection of the backplane.
Click to expand...
this machine was thoroughly cleaned about 3 months ago by me, added a dual cpu tray,3.46 processors, new paste, repasted northbridge(pins were fine) used for a week and stored in a warm damp closet and thats where i think i made the mistake. everything was working at that time. i was keeping it as a backup. i have another 5,1 in current operation luckily
 
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