Thought of sharing what I found. Recently managed to fix my spoilt unit due to the broken motor driver. Went to Simlim tower and bought the replacement part, in solder existing one and replaced it.
1. To open the unit, flip and unscrew the 2 screws at the bottom side.
2. The circuit inside is quite simple.
The heart of the unit is the Microchip PIC 16F877A microcontroller that controls the display, buttons and timers.
It uses transistor array IC ULN2003a to drive the motor. There are 2X of this. Therefore it should be able to actually drive up to 14 motors. We can see 2 female sockets on the board for extending the pump units.
It uses a button cell battery to keep the settings and clocks running when out of power supply.
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