I know little about electronics so your advice would be great.
One of my usb external drive enclosures has stopped working due to failed power supply.
Having opened up the power supply a capacitor (68uF 400v) seems to have blown (domed head) – nothing else looks pooped to my very uneducated eye.
Does this sound like the culprit? Worth changing? If so, can I replace with a bigger capacitor as Maplin don’t list a 68uF 400v radial capacitor.

so long as it’ll fit, the capacity isn’t too much bigger and the voltage rating is the same or higher it’ll be OK. By too much I mean 100uF or 147uF would be OK, but more could possibly cause issues with inrush current

Is the blown cap one of the main smoothing capacitors? It sounds a bit small in value. Are there bigger ones? Sometimes smaller value caps are put in parallel to provide high frequency smoothing.

It it’s not the main one, it may well not be the the cause of the problem.

Give it a go, caps are cheap.

I fixed an £80 DAB radio/ipod thingy with a 37p cap.

glenh: it’s the biggest one in there. Think I’ll try it anyway, nothing to lose.

I dropped 50 quid’s worth of laptop power supply one evening, it broke, flight out the next day, needed the thing, Christmas so impossible to get a replacement. I hacked it open and spent a good hour poring over it with my glasses off. Found a cracked joint – soldering iron, job done 🙂

Domed head = failed cap.

There was a spate of capacitor-related electronics failure a few years back. Google “capacitor plague”.

Domed head = failed cap.

I learnt about this just before christmas when our sky hd box started messing around. Turned out it was a failing power supply. So common you can buy a kit of capacitors to replace the originals.