Topic: Trouble shooting slim turning off after a few seconds

Hey everyone so I've been trying to bring my slim back to life, so far unsuccessful.
Issue: it will shut down after a few seconds and give a few beeps before turning off.

What I've tried so far: Ive dusted it out, tried a different power cable. Cleaned the thermal paste and reapply. And last I've bought a new power supply and swapped it out with no luck.

Now funny thing after reapply thermal paste and reassembling it booted back up just fine and ran for and hour or 2 then I shut it off. Wouldn't turn back on when I tried again.

Any ideas?
It's a 2101a

could be a few reasons that its forcing itself into a shutdown protection mode. Based on your 'experience', It may well be a dry joint - potentially on the APU itself. The solder that holds the pins to the APU sometimes melts from around the Pin and loses proper contact to the board. That then forces the shutdown as a safety measure.

Its often what caused the RROD & YLOD (in fact, that's where I'm at with my PS3 Phat - YLOD after replacing all the Thermal paste - booted but shut down quickly after) - not just the Thermal Paste drying and becoming less and less affected, but the heat causing other issues. At the point you are at, I'd personally be taking it to a professional to look at. After ensuring you have done everything you can to replace all the thermal contacts - including on RAM chips etc too, if that hasn't helped, I wouldn't want to mess with the soldering and certainly wouldn't want to give out any advice that contravenes this 'site' rules or techniques that 'could' work to fix it but also could cause irreparable damage if you don't do it exactly right.

The most 'likely' in my opinion is a 'dry' joint somewhere that's causing the system to Shut down so the only advice I'll give is to seek out a professional repair.