MP 1,1-5,1 Mac unable to read RAM slots

[joelgg]

I've recently had to replace the rivets on my Northbridge due to overheating of the Northbridge die. The Northbridge is now at a better temperature (still a little high though). It doesn't randomly reset anymore, which was the main problem!

Now I've got a few RAM slots which my Mac is unable to read, along with this red light. I've had this problem before, but the RAM slots that couldn't be read were in different places. I tried swapping the RAM around but the same slots are still unreadable. There isn't anything else which seems to be overheating.

 

[joelgg]

Is it the memory modules or the slots?

 

[tsialex]

Is it the memory modules or the slots?

It's the CPU socket pins or, much less chance, the CPU itself. If it's a MP4,1, check if the heatsink is correctly installed too.

 

[joelgg]

Looks like there's a pin bent on CPU B and some more flattened than others on CPU A

 

[tsialex]

It's very difficult to re-align pins, but not impossible, just need lot's of patience.

Before doing it, look at the pins from various angles and do very small/delicate corrections.

 

[joelgg]

It's very difficult to re-align pins, but not impossible, just need lot's of patience.

Before doing it, look at the pins from various angles and do very small/delicate corrections.

Ok, thanks mate. Will make sure to watch a youtube video or two before hand. Is CPU A ok? Or is it just B that's dodgy.

 

[tsialex]

Both.

See your photo with the red LEDs lit showing DIMMs not working, you have one lit LED for each socket.

 

[joelgg]

Both.

See your photo with the red LEDs lit showing DIMMs not working, you have one lit LED for each socket.

I did manage to straighten them (I think) but still have the red LEDs. Is it a matter of trial and error?

 

[tsialex]

I did manage to straighten them (I think) but still have the red LEDs. Is it a matter of trial and error?

If you change the DIMM that is showing the red LED to another slot and the red LED moves to it, the DIMM is defective.

Like I said before, getting a damaged 1366 socket to work again is a difficult job, you need to get the pins to almost perfection to eliminate all problems.

Some people prefer to replace the socket altogether, but this is only possible if you have access to $10K+ of repair equipment. AliExpress sellers used to have the 1366 socket that can be used with MP4,1 CPU tray.

 

[rx78]

Sorry for posting on an old thread but I just came across a similar problem, dual CPU 4,1.

RAM slot 1 is unusable and has red LED light, moved that DIMM to slot 4 and it's fine, no LED light on slot 1's diag LED. Not much of a loss to me as I only used 24GB to begin with and I think it happened with I bent one or two of the pins in CPU A, which I managed to realign but turns out I didn't do a good job.

I was wondering if the diag LED will light up on empty slots or only if it has DIMMs installed? I was thinking of getting more RAM for the B side but no point if I've killed some of B's RAM slots as well..... cheers

 

[Macschrauber]

Theres no red light for empty ram slots.

 

[rx78]

Theres no red light for empty ram slots.

I reread my own comment and realised how dumb it was

Guess I'll have to move a stick to B side and check before I buy!