MacBook Core Duo not working properly after internals were replaced
I just finished doing some major computer repairs on a 2.0GHz MacBook Core Duo. About a week or two ago, my mother was using her MacBook while drinking coffee and ended up spilling a significant amount of it onto the top case of the open MacBook. She called me about it and I was able to obtain the MacBook that night to do some heavy duty cleaning.
I took the computer apart entirely and cleaned up all the coffee I could using 91% isopropyl alcohol. After reassembly, I tried to power it on, but it was no good. The MagSafe light would not illuminate when any power adapter was connected and the logic smelled a bit like burned plastic, so I determined it was a dead.
I purchased a used, working logic board on eBay a few days ago and transplanted that into a separate MacBook Core Duo that I obtained from my brother using the iFixIt repair guides. His logic board had died of natural causes and none of the internals had ever come into contact with fluids, so they were fully operational. The only internal component I used from the MacBook that had coffee spilled on it was the hard drive, but it was not damaged and was tested in an external enclosure, so it too was operational.
I finished reinstalling all the internal components today connected the MagSafe adapter. The light on the adapter came on this time and the battery indicator lights are blinking and rising, so the logic board is receiving power. Upon power up, the optical drive sounded, but it just kept cycling. I didn't hear the fans power up and all is silent, but the cycling optical drive. So I'm not sure what problem there may be now. Could someone provide some insight given the symptoms I've described? Let me know if you need to know more. Thank you so much, indispensable iFixIt community!
Update - 11/5/10 Repair Log
After trying all the suggestions that rdklinc provided, I compiled a log of my results in order to see if this issue could be further diagnosed. Here it is:
When powered on, the MacBook's optical drive and hard drive fire up, but the sleep light comes on immediately and stays steadily lit. No start up sound is heard and the display remains black.
The display I reinstalled is fully functional and there is no faint image on the screen. I have also connected a second fully functional display (see photo below) from another MacBook and still nothing comes up. This may rule out a bad display or inverter cable.
When resetting PMU/SMC, the sleep light would flicker, but no tone was heard after any reconfiguration.
I reset the PRAM, but nothing happened.
Initially one RAM card seemed improperly seated, but after removing both RAM cards, switching up the configuration, using different cards, and reinstalling the cards properly, nothing happened.
Reseat Internal Connections
I opened the MacBook again, disconnected all internal cables and reconnected them all, making sure they were properly and securely seated.
Disconnecting/Replacing Optical Drive Cable
I replaced the optical drive cable with another. This initially improved the optical drive's cycling issue upon start up and it operated and sounded normally. After trying to start up with the hard drive disconnected, it went back to cycling. This optical drive is known to be fully functional.
Disconnecting Hard Drive
I disconnected the hard drive cable and attempted to start up the MacBook, but the sleep light did not illuminate and the optical drive started cycling again.
I got an email back from the Beta Macs company and a phone call from the rep I was emailing with about the logic board yesterday. They said they tested the board in a different machine and that it worked fine for them. I don't know if something they're doing is different from what I did, but the rep called me to tell me that my issues may be from improperly installing the temp sensors and not using thermal paste during reassembly. I'm certain I did both properly with the aid of iFixIt guides. What do you guys think, could it, in fact, be something on my end? I mean, I've tried all the things you suggested to get it working. Beta Macs has fully refunded me the cost of the logic board and the shipping. I've been thinking about ordering the only 1.83GHz 4-wall logic board that iFixIt has in stock, despite it being $100 more than the previous board that I purchased. I feel like there is a higher degree of functional certainty from iFixIt. What would you guys suggest? Once again, thanks so much for your help! You guys have been incredible.