Jeff,

We're in the lighting controls game and subject a percentage of all our
products to a "burn in" or, to use a better term, "stress screening" test.

For us it is our primary source of reliability information.  It's function
in terms of catching systemtic problems in manufacture is secondary (99% of
those should be picked up at MDA and functional testing)

We do not test 100% - we start at 20% and reduce it as historical data
indicates is reasonable (for some products (for which we have a lot of
data), we are only screening 3%).  As for temperature, we aim to get as
close as possible to (but not exceed) maximum operating temperature of the
product.  Our test duration is typically 48 hours.

So, yep, I think it certainly has a place, but regular assessment to ensure
it is still providing useful information is not such a bad thing either.

I guess it depends on the product and Class, but "burning in" or "screening"
100% sounds excessive to someone producing Class 2 - you could probably
reduce the percentage greatly without a huge drop in data quality.

Richard van Beveren
NEWTRONICS PTY LTD




-----Original Message-----
From: Landes, Jeff [mailto:[log in to unmask]]
Sent: Tuesday, 9 April 2002 06:46
To: [log in to unmask]
Subject: [TN] Powered up burn- in test


Hi all,

Historically we've subjected our units to a "power on" 11hr "burn-in" at
125F (prior to final testing).   This burn-in costs very little to perform,
since a hot room is already set up.

There has been talk of discontinuing this practice -- In fact the subject
comes up at least once a year.

Question....  Is it not just good practice to have a unit powered up for a
period of time before shipping it to an end user?   Otherwise it has only a
minute, or so, of history (during test) under power.  Is it not "better than
nothing"?

Any feedback would be appreciated.  What are others doing out there?

Jeff

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