For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
Fan spin for about 20 seconds. I believe I'm getting all the other vcore rails but noticed 0V @PPVCORE_S0_AXG diode there to Ground is 0V. Can I isolate and then run voltage to find the short? I noticed a ton of caps would be possible otherwise?...
AHHHH... ok. well chasing down rabbit holes. THis shows USB activity (flashing on usb drive) but can't get a pram reset out of it or chime... No image/backlight. Had the heatsink off would that cause turn off as soon as 20 seconds?
When this board really boots, VCORE drops to 0.78V aprox.
Check voltage on output pin of L7510/20.
If you get USB activity, board boots; but VCORE doesn't respect known patron in your case.
Nice! Ram card was doing something to prevent stop progress at least. Switching Ram card out (either slot) I now get USB activity. BIOS Chip was swapped already today.
no chime/display image/backlight. No external display activity detected. Smc reset registers. Cant get it to pram reset.