Following on from Sleepy iMac, here are some capacitors that might be a good fit.
I was provided with a second hand G5 iMac 1.8 GHz (A1058) PowerMac 8.2 (not A1144). Unfortunately, it overheats and then shuts down, or rather, goes to sleep, shortly after being powered on. This self imposed sleep happens quickly, especially if the processor is being pushed, such as by running a full screen video in VLC.
Looking for an internal 2.5″ 2TB HDD for your MacBook, or MacBook Pro? The cheapest option is to get a Seagate Backup Slim USB external disk and rip its guts out. It is the only 9.5mm 2.5″ 2TB internal disk on the market (or was in 2015), and I believe that it still is – even in late 2017, in Bangkok, an internal disk such as a Seagate BarraCuda ST2000DM006 2TB 64MB Cache SATA III 6.0Gb/s is around 3350 baht, or more recisely:
whereas the Seagate Backup Slim is normally 2620/2590 baht (depending on where you shop), or 2360 on offer (I actually ended up paying 2290 baht at a sale, with a soft case and a OTG mobile adapter thrown in).
Other disks are too fat (i.e. tall) at 12 mm to fit in the MacBook internal disk bay – other heights may be 6 mm or 15 mm.