Schrieber / Servis / hygena / Diplomat – F/F help needed.

Schrieber Integrated F/F
APM6855 (038103003)

Firstly I visited the machine to find the motor fan open circuit, this was replaced. The machine was defrosted in the process.

Two months later the customer phones again complaining of the same problem (fridge not cooling – freezer is fine). This time the fridge is running the fan (constantly), but the cooling radiator was blocked with ice.

I pressume that I missed this side of the fault on my first visit, it seems the constant running of the fan caused it to ‘burn out’.

I have gained access to the terminal board, This is where i need help…

I have Ohms readings for the two sensors at room temperature (one white sensor, one brown sensor), the two thermo-fuses (little black rectangles) and the defrost heaters, they are as follows:

Brown sensor – 4.03k Ohms
White sensor – 4.24k Ohms
Both of the thermo fuses have virtually no resistance- 0.01 Ohms
Defrost heaters – 0.316k Ohms

Please can someone advise me as to whether these measurments are acceptable or faulty. My instict tells me it is the PCB not turning the defrost heaters on.

Customers is getting irrate!!!

Sorry for the walll of txt – many thanks for reading – Daniel