Not charging, testing and troubleshooting

Howdy y’all, I am attempting to diagnose why my Shark stopped taking a charge. No green led when plugged in and battery is getting lower and lower.

I checked the wall adapter and it still outputs 24V. I took the whole thing apart and tested voltage all the way around. When plugged in no charging voltage reaches the battery. At this point the battery is depleted, so I took it out and manually charged it on a bench power supply and the battery is now fully charged and is also not the culprit.

I traced charging voltage back to the input to the circuit card attached to the on/off switch. Noticing 2 years of dust buildup I carefully clean it to get some pictures of the components. I hear a high pitched oscillation from the IC chip, but no output voltage to the battery.

I am asking if anyone knows how to order one of these circuit cards, as I’d much rather replace that than take it out and desolder these tiny smd components on my lunch break.

Oh yea, I should have mentioned I’m an electrical engineer, so I have the capabilities to reverse engineer and replace one tiny component on this board but is it really worth all the effort for a $60 vacuum??

I hope I can locate one of these cards and just swap it out and go.

Thanks!