Joyo DR J D-54 Shadow Echo - Repair

[ilcaccillo]

Hi,
I have a Joyo Shadow Echo D-54 that I need to repair.
It's a Delay with modulation.

The modulation part is not working properly and oscillating.

Does anyone have a schematic for this pedal?
Or does anyone know in what pedal might this one be based or copied from?

Thank you