No Clean Flux (Alpha OM5100) low level analog interference

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We assemble for a customer that is having an inconsistent lo... - Apr 13, 2007 by T.E.A.M. Services

This is sort of interesting. We had a clock problem with Al... - Apr 13, 2007 by

Even though this is a "no clean" flux, are you (or the custo... - Apr 13, 2007 by jmelson

T.E.A.M. Services

#49034

No Clean Flux (Alpha OM5100) low level analog interference | 13 April, 2007

We assemble for a customer that is having an inconsistent low level analog interference we believe with the no clean flux residue from Alphas OM5100 solder paste. We are considering testing Amtechs 4300 water washable no clean paste. We will test both production performance and circuit functionality during the qual process Anyone had any past issues like this? Or any good things to say of Amtechs product, wash or not?

Thanks

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flipit

#49036

No Clean Flux (Alpha OM5100) low level analog interference | 13 April, 2007

This is sort of interesting. We had a clock problem with Alpha OM-338 lead free paste. The flux residue was causing a clock problem and the clock was only a few KHz. We went back ot OM-5100 lead paste and the problem never occurred again.

Chris

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jmelson

#49037

No Clean Flux (Alpha OM5100) low level analog interference | 13 April, 2007

Even though this is a "no clean" flux, are you (or the customer) cleaning the boards? If this is truly a low signal level device, there is no way you will get away without cleaning the flux residue. I do a lot of low-level hardware, and we have to clean a number of the assemblies, sometimes even after someone has just HANDLED the boards! So, it is not just flux residue, but any hygroscopic contamination on the board. We have some gear with microvolt signal levels and 500 V DC on the same net, those are the biggest source of trouble. The tiniest contamination will cause leakage of the high voltage, resulting in noise.

Jon

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