I have in my bench a couple of BlueSky satellites (Mk1 of their pm3 THX certified series) that constantly blow BOTH transistors :S.

I'm not really sure how to even start looking for the problem elsewhere. The unit stopped working and was blowing fuse after fuse and I noticed some discolouration around the transistors. With some testing I realised both transistors were dead but replacing them didn't solve the problem.

Any ideas?

  • Finding the errors in electronic circuits is a complex magic that has very little relations to using them. You probably should contact Blue Sky about that. Feb 7, 2011 at 9:52
  • Meta discussion on this question here.
    – BenV
    Feb 7, 2011 at 18:51
  • 1
    The issue could be cause by thermal runaway because of mismatched transistors or poor design (the latter most likely if this is really this issue). I'd suggest searching to see if other people have had this issue (to rule out poor design). If it isn't a common issue a fried component may be causing this (most likely a blown capacitor/filter). If it can't be sent back to the manufacturer for a fix/replacement, I don't suggest trying to fix it yourself. Large caps in amps can still store a lot of electricity even when the device is shut off (big ones can really hurt you).
    – Evan Plaice
    Feb 10, 2011 at 23:43

1 Answer 1


I'm going to suggest you take these units in to a proper electronics service center and have them checked out by someone who troubleshoots this sort of stuff on a day-to-day basis. Normally I'd be all for going it DIY but you're dealing with high powered electronics. There is no room for error here. If you screw this up the result could very well be death.

Blue Sky's contact page lists their global resellers. If you're not in the USA you'll probably need to get in touch with the local reseller to figure out who might be authorized, near you, to service them. You could start by emailing [email protected] though.

If you're not concerned about warranties and such on them, just about any audio-oriented repair shop should be able to troubleshoot this kind of thing. The amplifier topology should be common enough. Anyone who deals with home theater amplifier repairs or if you've got pro-audio repairs for sound support should be able to take a look at them for you.

  • +1 don't fix it yourself if you can't get the manufacturer to fix it. Take it to a repair shop.
    – Evan Plaice
    Feb 10, 2011 at 23:44

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