Frying PCMs like there’s no tomorrow

Hi there, desperately needing help. We are on our 3rd fried PCM. Right now our cirtuit is the most basic: compressor, two tanks, one two state solenoid valve and one actuator. A chip in the center of the PCM keeps getting fried.

This happens when we are activating the solenoids. compressor starts charging properly and then this happens.

Any idea what might be going on? Why would this fry this way rather than protecting itself somehow?

We fried PCM’s in the past. Does your air compressor have a check valve at the output port? If not, the compressor has to overwork. The check valve keeps the pressure from backfeeding in to the pump head. If it does backfeed the compressor has to work harder as the pressure builds. The check valve stops this from happening.

We don’t have a check valve in the output of the compressor, we can add that. Just want to make sure that what’s frying is related to the compressor and not the solenoids

Are you using 24V solenoids with the 12V PCM input or vice versa?

We were the first time, but fixed that since. Now is 24VDC solenoids with 24VDC selected. Last time we had just one solenoid connected

One of the things is that we were using an older AM-3227 compressor that can pull up to 16 amps… switched now to a newer Viair compressor, max 12A. Hopefully will be better.

The viair compressor should have the check valve installed from the factory.

@ozrien can y’all help ID the component?

OP - emailing CTRE support directly is a good step.

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Our team always powers the compressor via a “Spike” H-Bridge Relay rather than via the PCM to avoid such issue.

Example with REV Pneumatic Hub and its integrated pressure switch port: FRC2495-2023/Compressor.java at main · FRC2495/FRC2495-2023 (github.com)

Example with CTRE Pneumatic Control Module and Digital Input on Rio for pressure switch: FRC2495-2020/Compressor.java at master · FRC2495/FRC2495-2020 (github.com)

Just did that. The component is quite fried to see, but seems to be an IR MOSFET, so the guess is that this is the driver for the compressor.

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We are currently working with CTRE to diagnose the faul. It seems to be related to the control of the compressor. Will update if we can figure out the root cause and the resolution

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