On off button not working

I got one of these in a Goodwill lot I bought online recently. It showed no life at all when the power button was switched on. I started to disassemble it per the motherboard replacement video, and while futzing around accidentally turned it on. And it responded normally. But only WITHOUT the top rubber button assembly on. Once I tried putting it all back together, it returned to bricked status. But simply pulling off the top rubber button assembly restored it to full function. It pairs via bluetooth fine, charges fine, the buttons themselves work fine, but only with the top cover off. My theory is that the rubber is pressing on the buttons too hard and keeping the power from working right. I should mention that mine also does not like full volume. Gradually turning up the volume causes it to reset the bluetooth connection until volume is lowered so maybe a sign of a sick motherboard or a loose connection internally. I didn't find it to be particularly bass heavy although it comes with a "special" rubber pad it is supposed to sit on for enhanced bass and it touts bass response all over the box. My DOSS Soundbox is an overall better speaker and my Monster Roam 2 is the heavy hitter. The fact that it works at all is a bonus for me even if it is crippled.