MP 1,1-5,1 Mac Pro 4,1>5,1 No boot chime...Sometimes... Please help!

[taiji212]

Hi all,

My 4,1>5,1 won't make it to boot chime. If I keep trying, it will eventually boot and operate normally. This takes anywhere from 1 to 6 attempts. Sometimes, a SMC reset helps. Sometimes it doesn't. I have tried multiple PRAM resets, no improvement.

This all started after upgrading to 1x x5690. I have tried reinstalling the CPU/heatsink, removing RAM/GPU. I tried replacing the internal battery. I also have a GTX 1080, but the issue still occurs even if I revert to the old Radeon HD 4870.

Maybe time to replace PSU? Pixlas Mod? Any thoughts? Thanks!

 

[KeesMacPro]

Hi,

It's recommended to list the hardware and software installed to give the reader a clear overview .

If the issue started after the CPU upgrade i'd reinstall the OEM CPU and start testing with a minimal setup and (if possible) a clean installed OS .

Did you check/replace the NorthBridge rivets?

This is the Technician Guide for troubleshooting:

https://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf