[ GoPed ESR ] Do "Flux Capacitors" typically go bad? Pics inside

[IlChengis]

Hi Everyone,
I'm trying to make a functioning ESR out of two broken scooters.

Parts I have:
- 1x charging board
- 2x "Flux Capacitors"
- 2x controller boards (see images here: https://imgur.com/a/qTMn9IW)
- 2x motors (silver body and black body - both functioning, tested with bench power supply)
- 4x brand new deep-cycle SLA AGM batteries

I assembled one ESR out of the two, but it won't turn on. If I plug it in to the AC outlet, the LEDs flash progressively as one would expect when charging... but pressing the red switch won't do anything. Tried both controller boards, both "Flux Capacitors" and both motors, same behavior. Checked DC voltage at the controller board and I am getting 25.x VDC to it, as expected.

Any idea on what to try next?

Thank you in advance!

PS= my goal was to get one ESR running in "stock state" and convert the other one to a brushless Li-Ion beast at a later time.

[ESR_RSE]

Where are you located? The power on switch is simple ground connection so the throttles should not go bad. Then showing the charge seem to show that the throttle is connected/working.