I suspect that what you are looking for is a Capacitor. MKP 50 makes me suspicious that it is a 50 micro Farad but I am not sure. Can you attach a photo of the component with the numbers showing. There should also be a number followed bu WVDC or WVAC. This is the voltage limit of the capacitor and it is important that the new capacitor have this same value or a greater value. Send the picture if you can and I will try to find a replacement. Are parts still available from the manufacturer? That may be an option too.
This appears to be a 50 microFarad 420 VAC Capacitor. You should be able to find an equivalent at a company like Grainger in the US or most electric motor repair shops stock capacitors of this size.
