On Thu, 31 Mar 2011 09:24:40 -0700, John Robertson
wrote:

An infra-red camera might be of use...or wet-touch each cap after its
been running a while (without exploding).

I use a cheap IR thermometer with a bit of creative optics to narrow
the viewing angle, or a thermocouple thermometer. I need my finger
tips functional for playing piano, organ, synth, etc. What I found
odd on the GX-520 board with the backwards capacitors, was that they
did NOT become warm:
http://groups.google.com/group/sci.electronics.repair/msg/feb66e8acd3d46a4
I measured the temperature and the capacitors were the same
temperature as the surroundings. I would have expected them to get
warm, but apparently not. My guess(tm) is that the plastic insulator,
between the foil wraps and the aluminum case, is also a fair thermal
insulator. While the electrolyte is getting hot and boiling off
belching gasses, there is little heat transfer to the case.

If you haven't broken it and then fixed it, you don't understand it.

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