January 12, 2023

Hacking the Fresh Roast SR800 home coffee roaster - power and temperature sensor

First, here is the circuit for the temperature sensor, almost certainly an RTD.

Next here is the 12 volt "raw" power supply circuit (on the power board) along with the signal delivered to the zero crossing detection circuit (the LM368).

Finally, here is the circuit on the logic board that develops the 3.3 volt supply for the PIC chip from the 12 volts from the power board.

Have any comments? Questions? Drop me a line!

Tom's coffee pages / tom@mmto.org