How to test Electrolytic Polarity?

[funkylowtones]

A buddy gave me a EA Tremolo build kit from Mammoth Electronics that he build up but he can't get it to work.
Upon asking him about the build and after quick inspection, he admitted that he may or may not have paid attention to the polarity of the electrolytic capacitors, of which there are four, on this build. And, since they have been soldered and lead have been cut ...

How does one test the polarity of a electrolytic capacitor?

Thanks

[slacker]

Radial caps, the ones with both leads at one end normally have a stripe or some other sort of marking on the case, this is the negative side.
Axial caps, ones with a lead at either end, often have arrows on the case pointing towards the negative end.

[R.G.]

As noted, they're all marked. If you mean "how does one test if the cap is put in the proper way round", one can either
(a) look at the build documentation if it's available, and compare to the markings on the caps
or
(b) get out the voltmeter, set to DC volts, and measure the DC voltage on the cap pins. If the measured voltage is more positive on the (+) pin than the (-) pin, it's correct. If it's more positive on the (-) pin than the (+) pin, it's backwards.

Note that it is not acceptable to have the DC voltage across a polarized electro cap be zero in a properly designed circuit. There are bipolar (BP) and non-polar (NP) marked electro caps which can be used either way.