Well from your description, if it’s all accurate, it sounds like there could be 2 faults.
- an autofill fault, could be leaking to steam boiler during shots (wet steam, trickle from brew group), causing an overfilled boiler
- possibly a motor start/run capacitor fault if it’s a quiet hum and you don’t think the motor is turning. This could even be intermittent and might show as a struggle to reach pressure, especially when coffee is in the group.
In your machine (to save me looking back through lots of posts)…is the pump above the motor, or below the motor
P.S as long as the values for capacitance are correct and the voltage the same or higher, a much cheaper cap can be got from ebay it can’t be an electrolytic capacitor though. https://tinyurl.com/26l2exod