MP 1,1-5,1 MP CPU A & B LED Fail

[MacintoshDude24]

HI,

My beloved MP 1,1 decided not to boot today. MP will power up but not chime. There's power to the USB ports but the Keyboard CAPS light will not come on. After investigating, the cause looks like the CPU's, as the Diagnostic CPU fail LEDs are lit. When the Diagnostic button is pressed the trickle, power, CPU overheat LEDs etc. all light up yellow but the CPU fail LEDs' stay red.

I've tried all of the following:

SMC reset.
PRAM reset.
Reseated all cables.
Cleaned all parts with compressed air.
Cleaned and reseated the CPUs'/heat sinks with fresh thermal paste and swapped them over.
Booted with all peripherals including RAM/Optical Drives/SSD/Drives/GPU/USB 3 PCIe card removed.

I'm trying to find a way of figuring out if the logic board died or the X5365 XEON SLAED CPUs' have failed before spending any more time or money so any advice on how to figure which is the cause, would be most welcome.

Thanks!

 

[Snow Tiger]

HI,

My beloved MP 1,1 decided not to boot today. MP will power up but not chime. There's power to the USB ports but the Keyboard CAPS light will not come on. After investigating, the cause looks like the CPU's, as the Diagnostic CPU fail LEDs are lit. When the Diagnostic button is pressed the trickle, power, CPU overheat LEDs etc. all light up yellow but the CPU fail LEDs' stay red.

I've tried all of the following:

SMC reset.
PRAM reset.
Reseated all cables.
Cleaned all parts with compressed air.
Cleaned and reseated the CPUs'/heat sinks with fresh thermal paste and swapped them over.
Booted with all peripherals including RAM/Optical Drives/SSD/Drives/GPU/USB 3 PCIe card removed.

I'm trying to find a way of figuring out if the logic board died or the X5365 XEON SLAED CPUs' have failed before spending any more time or money so any advice on how to figure which is the cause, would be most welcome.

Thanks!

Well , did you fasten the two CPU heatsinks enough ?

Re-thermal paste both the Northbridge and Southbridge controller heatsinks with Arctic MX4 . Nobody thinks to do this any more . This may be causing the start up to abort .

But those red CPU LEDs are not a good sign .

 

[MacintoshDude24]

Hi,
Yes fastened the HS’s back in tightly. Didn’t mess with the NB/SB as not enough Artic Silver left but will order some and give it a try. Are they easy to remove?

‘But those red CPU LEDs are not a good sign .‘

Yea that does concern me, the MAC was not powered up for a few weeks and the weather was quite cold. Not sure that’s the cause but somethings gone wrong 🤔

 

[Snow Tiger]

Hi,
Yes fastened the HS’s back in tightly. Didn’t mess with the NB/SB as not enough Artic Silver left but will order some and give it a try. Are they easy to remove?

‘But those red CPU LEDs are not a good sign .‘

Yea that does concern me, the MAC was not powered up for a few weeks and the weather was quite cold. Not sure that’s the cause but somethings gone wrong 🤔

The dried factory thermal paste will act like an adhesive on the NB and SB heatsinks , so they will try to stick . But they are indeed removable by unclasping the wire clamps . Remove the old paste with high purity alcohol before you apply the fresh paste . I use cotton swabs with wooden sticks and also the end of a black stick to scrap off stubborn dried paste . Both the NB and SB are dies without an IHS , so make certain when you reapply the paste you place a very thin coating on the entire die ( shiny silver area ) .

 

[MacintoshDude24]

After i've reseated the NB/SB HS's I'll reinstate the original 2.66ghz CPU's and see if it works. Hopefully it will in which case, i'll just need to get a new pair of CPUs. TBH though, I'm thinking it'll be odd for both CPUs to have failed at the same time which makes me think the Logic board has failed ;-(

EDIT: Replaced the X5365's with the original CPU's and the result is the same (CPU Fail LEDs' lit on startup) so looks like the logic board has failed ;-( If anyone has any other suggestions, i'd be grateful.