Well I am now typing this on my previously 3 beep macbook air

In answer to my own questions above, I did remove the heatsink and baked the logic board.

I did it for 8 minutes at 180 deg C

Also reapplied plenty of new thermal paste.

It’s working beautifully so far.

Interestingly having applied the paste it is super quiet. Made me realise that before it had been really hot and noisy, so maybe it was the thermal paste causing the issue…

Hi Oztrail (and any others)

I had the three beeps and tried the various simple methods to fix it - PRAM, SMC, Diagnostics, Vacuuming the inside - with no luck.

So I’ve now removed my logic board argh. Plan is to oven it.

I was just wondering before I put it in the oven if it could’ve been the thermal past that was the issue?

When I removed the heatsink it came away instantly without any resistance. The thermal paste was dried and chalky and I can’t imagine did a thing.

Is this normal? Or should I try a simple step of applying new paste before baking my board?

Any thoughts would be great!

Oh and I assume you baked without the heatsink in place, and reattached it after baking with some new thermal paste?

Thanks for any thoughts - I’ll post back my experience