HB-25 motor controller

ProboticsAmerica

Anyone run into this and have a fix?

I buy a fair number of HB-25 motor controllers. Every once in a while we get one that whistles whenever it is on and not moving a motor. The sound is very high pitched but consistent and is more audible to young people. In the past I've just figured that it was something weird going on with my wiring and/or a slightly off neutral position plus low power PWM switching, but today I happened to push down on one of the chips on the board and the whistling stopped completely. Through trial and error I found that if I or a nonconductive tool pushed down on the second largest chip visible on the top side of the HB-25 (the one adjacent to the letter P in Parallax) the sound would stop - always. There does not seem to be any broken or incomplete solder connections though in theory there might be a hairline crack that I couldn't see given where the controller was installed.

Anyone run into this before? If so what did you do to get it to stop whistling without having someone there pushing on it?

sam_sam_sam

I also found that battery power tool also do the same thing I am not sure what it is·or where is comes from

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any··that you may have and all of your time finding them

·
·
·
·
Sam

Franklin

Try a small spot of hotmelt on the open sides. Not too much as that chip gets hot and needs to breathe. It should have thermal paste under it and that should be damping the noise but it sometimes fails to do so.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen