crwdns2933423:0crwdne2933423:0
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crwdns2934243:0crwdne2934243:0 Dan

crwdns2934249:0crwdne2934249:0:

Did you have any luck with this? I have a Mac Pro 4,1 (single CPU) that is exhibiting the same symptoms. It was on 2 days ago, now no power on at all.
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+'''UPDATE 07/12/2017'''
Hi Max Entropy! Thanks for the quick and detailed reply. (I'll stick to replying to this thread, instead of starting new answers...)
I, too, have a second working machine, but I've yet to start the process of swapping components. My hunch is the same as yours — a surge has damaged the power system on the backplane board. The diagnostic button shows 5V on the backplane board, but jumping the SYS_PWR jumpers has no effect, which is all the detail that the ''Apple technician guide'' goes into.
So, I don't have any questions right now, but I would be very interested to hear how your new power chip works out.
Thanks again.

crwdns2915684:0crwdne2915684:0:

open

crwdns2934245:0crwdne2934245:0 Dan

crwdns2934249:0crwdne2934249:0:

Did you have any luck with this? I have a Mac Pro 4,1 (single CPU) that is exhibiting the same symptoms. It was on 2 days ago, now no power on at all.
+
+
+
+Hi Max Entropy! Thanks for the quick and detailed reply. (I'll stick to replying to this thread, instead of starting new answers...)
+
+I, too, have a second working machine, but I've yet to start the process of swapping components. My hunch is the same as yours — a surge has damaged the power system on the backplane board. The diagnostic button shows 5V on the backplane board, but jumping the SYS_PWR jumpers has no effect, which is all the detail that the ''Apple technician guide'' goes into.
+
+So, I don't have any questions right now, but I would be very interested to hear how your new power chip works out.
+
+Thanks again.

crwdns2915684:0crwdne2915684:0:

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crwdns2934241:0crwdne2934241:0 Steve

crwdns2934249:0crwdne2934249:0:

Did you have any luck with this? I have a Mac Pro 4,1 (single CPU) that is exhibiting the same symptoms. It was on 2 days ago, now no power on at all.

crwdns2915684:0crwdne2915684:0:

open