Question Laptop is fried, trying to determine if it's the MOBO or CPU, and if upgrading the CPU is a good idea ?


Oct 5, 2002
I have a Lenovo IdeaPad G780, and I really like this laptop despite how old it is. Specifically it's this model:

That's even the link I bought it from years ago.

Issue is... it's dead. I accidently fried it while I was trying to repair cracking hinges. After doing the repair and testing to see if it worked, it was powering on fine, but I realized I had forgotten to plug in the RAM. So I powered it off (or I thought) and unplugged the AC adapter. Problem was, it had not actually fully turned off, and the normally 100% dead and shot battery I had forgotten to unplug decided to live that one time just long enough to keep the system powered on as I installed the RAM module.

The system just flashes a white screen now and has a burning smell if I attempt to power it on. It's clearly fried, but I don't know where or what component. This was a while ago, and since it's just taking up space I decided to check eBay to see if anyone would buy it for parts even though I REALLY don't want to give it up, and that's when I noticed that I could get a replacement motherboard for this exact model for about $60-70.

What also caught my eye is that none of them had a CPU, instead there is a socket. I had no idea my laptop's CPU was socketed, those are extremely uncommon.

Now though it makes me wonder what component could have fried. If it was something on the motherboard, or possibly the CPU itself since IIRC they started putting the memory controllers on the CPUs long before this laptop was made.

Is there any way I can really find out if I don't have a donor board I can test the CPU in? Would it even be a good idea to test the CPU that may or may not be fried in another board or could I risk frying that board too if it's the CPU?

That's also what got me wondering, since the CPU is socket, this means I might be able to upgrade it too and avoid that problem alltogether. I checked the list of CPUs within that generation here:

And one issue that I noticed is that my CPU, the i7-3632QM, is a low-power variant with a TDP of 35W. The others have a TDP of 45W or 55W.

Now, I am not going to plonk down $150+ for some extreme edition Core i7-3940XM, but would I risk my laptop's cooling system not being enough for even the 45TDP ones over the 35TDP CPU I have? I was thinking something like an Core i7-3720QM or Core i7-3740QM as those are around the $50-ish range on eBay. The original CPU it came with also seems to go for around $20 on eBay.

And even if the cooling is enough, is there a chance the laptop's motherboard won't accept any CPU other than the one it came with? Or were all these standard enough that if the Laptop's motherboard is socketed, then it should accept the CPUs in that generation with that socket?


As I understand the sequence of events described in your post I would not expect the laptop to be worth any salvage attempts.

I am all for trying to fix, repair, reuse, recycle etc. but at some point the ROI (Return on Investment) is simply not there to justify the effort and cost.

"Burning smell" indicates that something surely is fried.

Unfortunately other components may not have been fried but are damaged in some manner that, while possibly working, could subsequently fail for any number of reasons.

You fix A (i.e. replace the CPU) - laptop works for awhile and the B fails. Fix B. then C goes. Etc. etc..

Or the replacement CPU goes right at the beginning....

If anything set a "replacement budget" and repair within that budget. Consider the money (50-ish) a bet and that if that bet is lost then do not "gamble" more.

Nothing in the laptop can be trusted and even if parts are salvaged they remain suspect and should only be knowingly used where a sudden failure will do minimal harm. Properly recycle everything else.

Just my thoughts on the matter.
Reactions: Phillip Corcoran