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U12 AO0 & AO1 problem

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#1 El San

El San
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Posted 06 August 2012 - 09:58 AM

Hello, My U12 analogue outputs (0 and 1) have a problem. They work fine for outputs form 0 to 2 volts but will not go above 2.2V for output 0 and about 2.1V for output 1 if I keep increasing the output voltage. I have read in the user's manual that applying a voltage to an output might damage it and produces a symptom similar to the one I just described. In fact, I think this is what happened because the op amp which my output 2 is connected to burnt and shorted its input to the positive rail resulting in +15V being applied to the U12 output. The strange thing is that both outputs got affected and following the procedure indicated in the manual to confirm that the outputs were damaged by the applied voltage I got that R63 and R62 had resistances bellow 50Ohm (18Ohm for R63 and 22Ohm for R62). Is there anything else I can check to try to repair my U12? Regards

#2 LabJack Support

LabJack Support
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  • 8677 posts

Posted 06 August 2012 - 01:41 PM

A single-chip dual op-amp is the buffer for both analog outputs, so even if you only hit one with a bad voltage it can affect both. If you want to try repair yourself we can provide more detail, but we will issue an RMA and attempt repair for free here if you want. Either way, send an email to [email protected]

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