If it was just the YLOD, Id say its not bad. But seeing as it doesnt turn on, its going to be a lot to get fixed. Sadly, the ps2 compatible systems are the ones that seem to be the most prone to all the issues.
With a YLoD, the system *won't* turn on.
It *might* beep, flash a red and/or yellow light...and power-off again, immediately.
Last I checked, Sony's going rate (for shipping + "refurbishing"/'fixing' that model was...~$100.00; I *think*
I have one of those & a slim -but-
soera's absolutely right about the bigger/older models running hotter; thus = more YLoD's :'(
The *best* run I've had with a launch model is ~2 years (with a lot of use).