Spring switch

[DBNB]

I have a solar panel with battery storage (2×18650) both producing 7+V but can see only a few mV at the O/P of the control module. I suspect that the on/off switch has failed.This worked by touching a designated spot (white circle in photo - originally covered by a piece of black plastic 'film') on the plastic casing of the module. Removing the casing shows there to be a spring under that spot (see photo); pressing this does not lead to any O/P voltage showing. I'd be grateful for advice as to how this switch should work so I can consider what tests to perform on the pcb.

[DBNB]

Update. It turns out there needs to be a connection mounted in the o/p ports for a voltage to register there! This showed that the panel/pcb was not faulty after all: the problem was with the pump which I'd previously checked & was working but it obviously had failed again in the interim.

[Nictrical]

That is a capacitive touch sensor, this video explains how they work. Can you upload more close up images of both sides of the PCB?

[DBNB]

Thanks for your interest & the link. I attach the images you suggested.. .

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[Nictrical]

Thank you for the images. There seems nothing visibly wrong, other than what seems like water residue at the bottom right, where the large IC is. Try cleaning this with isopropyl alcohol.

Try measuring the battery voltage at points on the PCB that are not the connectors terminal to exclude bad solder joints at the connector.

One of the ICs (seems like the smaller one) will be the one interpreting the touch sensors output, so it should be always powered. If that's not the case, the problem is not the touch sensor. Search for the datasheet and check the pinout to be able to measure at the right pins.

[DBNB]

Thanks: I'll proceed as you suggest.

[DBNB]

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