Hi

In our house we had a overvoltage due to an neutral conductor interruption. This led to high voltages and fried a part of our fridge. The only part that got fried is the surge protection, but I have a hard time finding the correct resistors because the color code got damaged.

The power supply part should still be fine. It consists of a TNY276P/G. Only the input with the current limiting resistors (I guess 4W or 5W) and the TVS diode (SMCJ400CA) got fried.



Here is a simplified schema:


As I understand, those resistors don't have any influence on the function of the power part and are simply to limit the current in a surge. With a clamping voltage of 648 and a Peak Pulse Power Dissipation of 2000W of the VDS, the current should be limited to 3A. This would result in a resistance of around 200 Ohm, or 100 Ohm per resistor. But this seam very high. Well i'm not an electrical engineer so this are only guesses. Can someone please help me with this?

Datasheets:
VDS
TinySwitch

 

Try measuring the resistance with an ohmmeter.

 

Yeah i tried that but as i mentioned the resistors are burned. There is nothing to measure.

I only need to know what a good value for the resistors might be. I don’t think it has to be a perfect match with the existing ones.