My speaker won't charge, the little white led kinda fades in and out?

Hi,

Have you tried a different charger or charger cable, you didn’t say?

If so, use a strong light and a magnifying glass to visually inspect the charge port to check that there is no dust or lint etc stuck in the enclosure making for a poor electrical connection. Also check that all the pins are there and that they are straight and parallel with each other and not broken or bent.

If there appears to be something there, do not use a metal pin or probe to try and clear the obstruction as you may damage the pins or cause an electrical problem in the speaker. Try using a vacuum cleaner to see if sucks out the debris. If still no good, use a sharpened wooden toothpick to gently remove any debris.

If it appears to be clear then perhaps the charge port has become loose on the systemboard.

Here’s a link to the ifixit Logitech UE MegaBoom Auxiliary Port and micro USB Port Assembly Replacement guide which should help you to gain access to the charge port to inspect it. If it is loose you’ll need SMD (surface mounted device) soldering skills and tools to resolder the connector back onto the board.