Testing Tantalum caps

[johndon2000]

On a previous post someone mentioned that Tantalum Caps have high failure rates and are a good point to start when faulty finding... if a board has 40+ tantalum caps is there an easier method of testing the caps other than taking them all off 1 by 1 and measuring capacitance?!

[Neilm]

The first time I had a tantalum cap fail it was obvious - the smoke, small flame and discolouration were a bit of a give away. The second time it had failed short circuit - so I just pushed lots of current through the voltage rail until I had the same give away as the first time.

[807]

Like Neilm, in my experience I've only come across faulty tantalums that have either exploded, or have gone short circuit.

Trying to find a S/C on the power rail of a piece of 70's - 80's test gear containing loads of tantalm decouplers without a ToneOhm can be quite difficult.

[KD0CAC John]

Just guessing here , but looking for shorted tal-caps .
Couldn't you just run not more than the rated current for the circuit in question and just measure excess heat ?
My idea being not to damage the device under test .

[vlf3]

From my experience the only way to be sure, is to lift one leg out of circuit, and ESR the little bugger... otherwise it's down to leaky or short. 

[vk6zgo]

Remove 'em all!

Once you've done that,there's no point testing them--just replace the lot!

Of course,that's how you would do it if you are doing it to earn a crust---man-hours cost a lot more than Tants!

A hobbyist may have other priorities!

[peter.mitchell]

Remove 'em all!

Once you've done that,there's no point testing them--just replace the lot!

Of course,that's how you would do it if you are doing it to earn a crust---man-hours cost a lot more than Tants!

A hobbyist may have other priorities!

Nah, just replace em all, stuff em'. Small Alu 'lytics are cheap as chips.

[Neilm]

Remove 'em all!

Once you've done that,there's no point testing them--just replace the lot!

Of course,that's how you would do it if you are doing it to earn a crust---man-hours cost a lot more than Tants!

A hobbyist may have other priorities!

Nah, just replace em all, stuff em'. Small Alu 'lytics are cheap as chips.

But they don't have as good a frequency response - so if doing that add some small ceramics in parallel.

Neil