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neant

macrumors newbie
Original poster
Oct 3, 2014
10
0
hello.. i have upgraded the mac to a 3,33 ghz hex cpu. After the installation the mac chimed but there was a blinking red light on the cpu tray , the computer closed itself after entering the OS.. it seemed like overheating so i made the heatsink more tight. Now the light blink a few seconds at boot time and stop.. the mac enter osx and seemed to be normal.. my question is it normal to have this red light blink a few seconds at boot ? i cant remember if it was there before.. thanks
 

h9826790

macrumors P6
Apr 3, 2014
16,656
8,587
Hong Kong
Which red LED? Any marking / name next to it (or a photo is even better)? From memory, the CPU overheat LED is on the mobo, but not the CPU tray. And the LED on the CPU tray is for the RAM.

How did you clean up the CPU, heatsink, and apply thermal paste?

Do your Mac has all the RAM recognised?
 

steveOooo

macrumors 6502a
Jun 30, 2008
743
89
UK
Ayone know What's the pin that's inside the heatsink does / is called? I managed o bend it whilst asking the heatsink off -

Skip to 1m49s:

 

rawweb

macrumors 65816
Aug 7, 2015
1,126
943
Which red LED? Any marking / name next to it (or a photo is even better)? From memory, the CPU overheat LED is on the mobo, but not the CPU tray. And the LED on the CPU tray is for the RAM.

How did you clean up the CPU, heatsink, and apply thermal paste?

Do your Mac has all the RAM recognised?

Agree, I've only ever encountered an LED on tray with ram issues. CPU stuff should be on LB.

OP, pull out the tray, take out the ram, mix it up (assuming all is matching), and reseat it. Could be that simple...
 

GygaBat

macrumors newbie
Sep 29, 2020
18
2
Italy
Sorry to sneak in, but is it a normal thing that the red led for the CPU A in a dual tray briefly blinks once at start up and EVEN ONCE at shut down?
Thnks !

EDITED

From the manual :

"The red-colored error LED on the processor board next to the memory slots at processor A should flash once only as the Mac Pro powers on."

and :

"If using dual-processor board, both the LEDs next to the memory slots should flash once only."
 
Last edited:
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