I just found a 2008 Macbook Pro 15" (trapdoor) that won't turn on. Battery charges fine.
I've unhooked the keyboard ribbon cable, and tried shorting the two power button pads for 10 seconds, but it still won't turn on.
If, when you open the “trapdoor“ (round here, we just call these the “aluminium MacBook Pro”) and look at the RAM bridge (which typically has a factory label with the logic board serial number and a bar code), if you do
not see a green-dot sticker which was added to the RAM bridge manually, then you have a unit with the non-revised version of the Nvidia 8600M GT GPU which had a design flaw, invoking failure. These units will have “G84-602-A2” inscribed on the GPU chip itself.
Nvidia corrected their mistake mid-stream during the production cycle of when the early 2008 MacBook Pros were still on sale (and late units have the updated GPU direct from original manufacture), whereas affected units were eligible by Apple to have the revised GPU swapped in. These factory/manufacturer/Apple-authorized units were affixed with the aforementioned “green dot”. On the revised version, the Nvidia GPU chip itself will have “G84-603-A2” on it. Here’s an example:
I don’t think you have a ribbon cable issue. What you have is the bad GPU. My 17-inch early 2008 had the issue when I got it in 2019. The MagSafe charger charges as one would expect (this is mostly because the power board is a separate piece from the logic board on these models), but the system won’t do anything when you try to power it on.
Is there anything else I can try?
Unfortunately, Apple halted honouring the GPU replacement a long while ago, as Apple do.
Fortunately, there are a few ways to get one with a working GPU:
1) MR forums member (and hacking wizard)
@dosdude1 offers a service whereby, if you’re in the U.S.,
he will replace the faulty GPU with the revised version. He comes highly regarded by past customers and the Mac hacking community. Unless his pricing has changed, he will do the swap for $150 (which may also include 48-state shipping, if my memory serves…
do check in with him, though).
2) Search various sources for a revised “G84-
603-A2” GPU to buy online from the usual places (like ebay, Aliexpress, and so on). [As recently as 2021, I was finding places selling these for less than USD$35.] Find someone locally who services Apple logic boards and components and who would be willing to provide a service similar to what dosdude1 does with the previous. (This is probably the more affordable route if you’re situated outside the U.S., as many of us are.)
3) Look around online for tested and working, early 2008/A1260 logic boards which indicate the GPU on the logic board is the revised, “G84-
603-A2” version (you might even be able to see this in closeup board pics). Typically, from item description photos, you should also easily see the green dot on the RAM bridge indicating the GPU repair was completed. (If in doubt, ask what GPU part number the board being sold is actually using.) Once it arrives, swap out the board. [Bonus: if your wasn’t the top-of-the-line 2.6GHz board, you might be able to find one to bump up your system from 2.5 to 2.6GHz this way. This was, ultimately, the route I followed. For where I was located, the price I paid was comparable or slightly better than option #1 (which he may do for outside-of-U.S. customers, but it’s up to the person sending in the board to handle all the customs paperwork and duty where they live)]. And, bonus, my old 2.5GHz MacBook Pro is now a 2.6 GHz MacBook Pro.
