Aporte original por: Philip Le Riche ,
I'd be inclined to doubt whether it's the flash tube itself unless you can see a visible crack in the glass (most likely around one of the electrodes) - there are probably more ways that the driving electronics could fail. If you can disassemble the flash head so as to remove the xenon flash tube you can get its precise dimensions and then you may be able to find a replacement on one of the Far Eastern online market places - it's almost certainly a generic part. But probably much easier to replace the complete flash head. There's one on ebay.co.uk currently for £42.50. Or you could put a watch on ebay for a SX40HS for spares or repair with a different fault, which could be cheaper. But a word of warning - the capacitor (the cylindrical part) may hold a considerable charge for a long time after you switch the camera off, sufficient to give you a nasty shock. Take great care around the flash head until you've had a chance to short out the capacitor terminals with a screwdriver with an insulated handle.