How to disassemble Cheap Chinese Wrist Blood Pressure Monitor Meter Cuff

I got ERR 1 in 2 devices.
Replace Eneloop batteries still didn't work.
Replace Alkaline batteries still didn't work too.
Use AMS1117-3.3V didn't work too.
But it works when parallel 2 AAA with 2 AA batteries.
I think motor is defect and plan to replace soon.
ZT030-01 Mini Pump
ZT1-3A Valve
DC 3V