MacBook Pro not turning on, no MagSafe LED

Hi everyone!

A friend of mine gave me an A1261 MacBook Pro without a battery or charger.

The Mac won’t turn on. I tried with a known good and fully charged battery from another 17”, no signs of life. The MagSafe LED (I’m using a 60W charger that works perfectly with my other 17” A1212 MacBook Pro) won’t turn on, it just flickers very dim and won’t charge the battery. Sometimes it will go blinking green or orange and I hear a slight ticking sound from the left side of the computer.

What could be the issue? I obviously already tried the SMC reset as well as the power pads on the logic board itself.

Thank you!

More infos:

here’s how the MagSafe light behaves (most of the times it comes on very dim and ticks every 0.5 seconds).

The ticking comes from the area in the picture below, and you can clearly hear it both in the video and in the audio note.

I measured the voltage on the 18.5V pins of the left I/O power connector on the main logic board and I get at best 16.7V, but I can’t figure out where the problem is.

I also tried the left I/O board from an older 17” (just the power connector, the other one is different between the two Macs) and it behaves exactly the same.

Plus, heating up that section of the board makes the green light come on solid for a few tries and I get 3.3V on the “power on” pads, but still the machine won’t power on.

Audio: https://www.dropbox.com/s/dk62w3jctscg5d...