Sam Goldwasser wrote in
:

That's what I thought. But in any case, I don't believe his problem
is a matter of destroying the triacs with excessive current since the
thing works after the problme occurs when taken back to the lab or
whatever. Possibly something in the driver circuit that's not turning
completely off.

Maybe a marginal design where the sign is in direct sunlight and the extra
heating in the triac increases the leakage so it won't turn off?

If so, bringing it back to the lab removes the sunlight and it now works.

One way to reduce the inrush current is to add a NTC resistor in series
with the AC line. This is used in ordinary PC power supplies, where the
inrush current charging the caps could be 50 times the normal operating
current.

Here's an article that discusses different methods of limiting inrush
current. It is slanted towards selling their new product, so some of the
numbers are skewed. But otherwise not a bad overview.

http://www.st.com/stonline/products/...re/ta/9115.pdf

Regards,

Mike Monett