I think my logic board is faulty - power issues

[Nathan1991]

Hi.

I have recently managed to purchase a 2008 macbook pro for £20, because it has some minor problems. I feel this is a failed logic board but am I right?

Firstly there is no working wifi, its not seen anywhere, not even in recovery.

Secondly and most annoyingly. The machine powers and runs perfect on mains and battery unless you leave it unplugged overnight.

It starts and runs on mains or battery every time and will run on battery for hours BUT if you leave it overnight without the charger plugged in, it will not turn on again unless you remove the RAM and put it back in.

When this happens the battery shows good charge on the side button and when you eventually turn the machine on. It then will run fine on battery and mains.

Thanks in advance

 

[Fishrrman]

That's why it cost you only £20!

 

[Nathan1991]

That's why it cost you only £20!

Exactly. I just wanted to know if it was a Logic Board issue I was looking at and not somehing easier to fix. I was aware of the fault when I got it.

 

[treekram]

For most of these models, the MBP has a separate "Airport" card for WiFi, so if that's failed, you can replace it. I see one site that sells a new replacement for the late 2008 MBP for $60.

The other problem is unusual (at least in my experience) - when you re-seat the RAM, are you disconnecting the power to the logic board before removing the RAM?

 

[Fishrrman]

Another thought:

Next time you do the "RAM trick" (removal and replace), replace ONLY ONE RAM DIMM.

See if it makes a difference.

If necessary, move the single DIMM to the other slot, then try again.

It -might- be a failed DIMM slot?

 

[BrianBaughn]

The overnight issue could be due to the old battery and the best way to find out is to put a known good one in.

 

[Nathan1991]

The other problem is unusual (at least in my experience) - when you re-seat the RAM, are you disconnecting the power to the logic board before removing the RAM?

Yes, Removed the battery (removable on this model easily) and no PSU connected.

Next time you do the "RAM trick" (removal and replace), replace ONLY ONE RAM DIMM.

I have tried this, both stick work individually, in both slots. One odd thing is that if I put both sticks in tougher the other way round I get no display at all and no boot.

The overnight issue could be due to the old battery and the best way to find out is to put a known good one in.

My genuine apple battery, original from new I think, has 250 cycles and I have replaced it with a non genuine battery. Still no change.

I do have a non genuine PSU but I don't feel this would effect how it functions on battery?

 

[Fishrrman]

OP wrote:
"I have tried this, both stick work individually, in both slots."

Are you saying that with only ONE RAM DIMM installed, the MacBook will boot up normally?

If the answer is yes, you've found your "solution".

That is... use ONLY ONE RAM DIMM, and be happy about it.
Buy a larger-sized DIMM if necessary...

 

[Nathan1991]

Are you saying that with only ONE RAM DIMM installed, the MacBook will boot up normally?

If the answer is yes, you've found your "solution".

No sorry I was not clear here. The fault is the same is I use both Modules or either module in either DIMM make no difference to my fault.

It starts and runs on mains or battery every time and will run on battery for hours BUT if you leave it overnight without the charger plugged in, it will not turn on again unless you remove the RAM and put it back in.

BUT if I swap the modules around it will power and not boot

 

[treekram]

If you can, get another pair of correct memory modules and try them out. I see that they're not that cheap new but if you have access to a used pair, that would be good. The possibilities I'm thinking of:

- Weird interaction between the two modules and the computer.
- Different specs for the two modules.
- Incorrect specs for one or both modules.

If the memory module has specs on them or if there is a part number, that would help. It would also be good if you can tell use what model 2008 MBP you have - the model number should be on the bottom case.