elskardio
Well-known member
Hi Guys,
What's your procedure to stress test newly built Discrete Opamp?
Thanks
What's your procedure to stress test newly built Discrete Opamp?
Thanks
Yup weeding out infant failures. Failure curves for most electronic products follow a bathtub curve where lots of (infant) failures occur right away then level off to a low rate, until end of life when they increase again.pucho812 said:when I worked for an audio manufacturing company we would burn in every discrete opamp we made for a period before evening testing and measuring them. if there was going to be a fail in what we did, it would go from the start. From there after burn in, we had a test jig where we could run them, it had test points to measure current draw and an audio circuit to measure it with an AP machine and listen to it if we desired. Between the burn in and measuring, we were covered so any listening would be when testing a unit with those discrete pampas.
so it's a log curve?JohnRoberts said:Yup weeding out infant failures. Failure curves for most electronic products follow a bathtub curve where lots of (infant) failures occur right away then level off to a low rate, until end of life when they increase again.
Back in the 80s before I went to work at a real manufacturing company. I would run (LOFT/Phoenix Audio) rack mount products in a burn-in rack overnight before bench testing. I had the burn in racks on a timer so they would cycle on and off every few hours to experience multiple thermal cycles.
At Peavey we used burn in racks for power amps/modules, but not over night (pretty much just confirmed that thermal protection and short circuit protection worked).
JR
PS I wanted to try using infra red cameras to help check power amp modules by looking at component temperature using an IR image but this was last century and the technology was not cheap and easy enough for me to get it happening. If this worked we would not only have simple go-no go test, but troubleshooting advice about what to check (i.e. this is too hot, or this is too cold).
pucho812 said:so it's a log curve?
Yes that has been my experience as well. We ran our discretes on the power jig for several hours and we could power upwards of 100 at a time. that jig took up a nice size of wall.
Seems like a reasonable thing to do, yes.elskardio said:Did you run the DOA at their maximum supply voltage when you were testing them?
Not necessarily, that depends on the circuit topology.One thing I noted testing multiple DOA is the variation in DC offset from one to another. I guess better the input transistors are matched, smaller the DC offset?
elskardio said:Thanks guys for the response... and sorry for the late reply
Did you run the DOA at their maximum supply voltage when you were testing them?
One thing I noted testing multiple DOA is the variation in DC offset from one to another. I guess better the input transistors are matched, smaller the DC offset?
JohnRoberts said:
Back while I was at Peavey we extended our warranty from 3 years to 5 years. I researched the service repair history and it was a no brainer... most field failures happen in the short term.
JR
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