For anyone who might find it helpful, I’ve just successfully repaired the board in my Velvetiser after it became unresponsive. I thought the last hot chocolate it made wasn’t as hot as usual, but it was only the next time I tried to use it I realised it was dead!
In my case, the SR2100 (Schottky diode) had failed short. It’s the one right on the edge of the board, nestled between the yellow transformer and the white connector for the temperature sensor. I replaced it with an SR5100 which is rated for 5A instead of 2A. The only downside is that the leads on the 5100 are too thick to go through the holes, but I successfully soldered it in place with one leg attached to the positive leg of the adjacent capacitor and the other side soldered to the surface of the pad with a bit of a blob.
I also replaced the smaller of the two IC chips (the SMD one), which is a ULN2001 MOSFET package. I’m not 100% sure, but I suspect I destroyed this myself during testing. It is used for switching of the 12V motor and the heater relay. The larger of the two ICs is the microcontroller.
If you have a bench power supply, 12V can be injected across the large green capacitor which is in the same area as the other components in question. This is much safer than reconnecting the board to the mains for testing and also means the heater will not receive power, just the relay. If everything is working correctly after repair and the button is pressed while injecting 12V, the LED should light up, the motor should turn, and the heater relay should click, but the heater should not get hot until the unit is connected back up to the mains.
I hope someone finds this useful and it can help prevent some e-waste! It’s also worth noting that the user manual for the Velvetiser states that the unit should not be left permanently connected to the mains, I suspect this is why!