Soniq flea market speaker repair

[griell]

Gday forum, I've recently found myself with a pair of soniq speakers. They sound great but have this annoying issue where the sound cuts out after 20 minutes (almost exactly). Power remains on for the system (as i can see an led still on when the sound cuts out) and the usb port still has power.

What ive already done:
tried a different power jack in the house
ran the speaker with the back panel off (thought overheating could be the culprit)
tried using different devices to play sound
tried using the bluetooth function instead of rca connection
checked the boards for dry joints, blown caps

Details on the speaker:
Soniq Flea Market bluetooth bookshelf speaker
model no. fmbtbss2bk
the right unit is a passive speaker with a separate amp + bluetooth + power circuit board, the left unit is just a passive speaker that can be connected to the right speaker with two wires.
I primarily use the speaker with an rca to 3.5mm aux splitter but it shows the same symptoms over bluetooth.


I'll attach photos of the circuit boards but I'd really appreciate if someone could point me in the right direction for diagnosis. I have some experience with electronic repair but am very new to sound system electronics.

[griell]

another board, this is what i suspect is the amp circuit

[griell]

And this is the final board which i assume is responsible for handling controls + bluetooth

[themadhippy]

but have this annoying issue where the sound cuts out after 20 minutes

do they have a sleep timer option?