I have a Macbook Pro 5,1 (late 2008) running El Capitan (10.11), which is the latest officially supported OS for that machine. When I turn it off I cannot turn it back on without resetting the SMC multiple times (sometimes up to 20 times, sometimes just once is enough). The problem only occurs when the machine is turned off for at least a few hours, otherwise it turns on perfectly. This makes me think, that there could be some kind of small battery on the logic board which drains too fast due to the age of the Macbook? It doesn't matter how much the main battery is charged.
What I've tried so far:
- quick Apple Hardware Test without any results
- used different RAM
- used different internal HDD
- resetted NRAM/PRAM
- installed a new copy of the OS and then imported everything (Data and Settings) with the migration assistent
Any other Ideas? Thanks in advance!