MacbookPro A1297 820-2914-A not turning on

Hi
This old machine is not turning on. I did check the voltages which i found normal except PM_SLP_S4_L. when i tried it in SMC bypass mode. It start booting but didn't properly. I had apple logo screen with boot bar and it kept rebooting in SMC bypass mode. PM_SLP_S4_L is coming from U1800. Could you please shed some light on it? what and where i have to work on?

Thanks
 

2informaticos

Administrator
Staff member
There is no problem with power on sequence, if machine boots in SMC bypass mode.
Some SMC sensor may prevent to boot in normal mode.
First be sure to use original 85W charger.

But looks like you have problems with GPU too, as machine never gets logged into macOS.
 
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