Failed door interlocks account for the majority of microwave oven
problems -
perhaps as high as 75 percent.

I was interested in the assertion that door interlock micro-switches are the
most common failure in microwaves.

I have just looked at our repair database and I have repaired about 280
microwaves over the past 18 months makes include Sharp - Panasonic -
Samsung - LG - old Toshibas & Sanyo.

I would say the most common faults are
1) Sharp CPUs
2) HV diodes
3) Magnetrons
4) HV capacitors
With microswitch trouble maybe joint fourth or maybe lower.

The situation of the Sharp CPU perhaps needs a little explanation.
Most of the ovens we repair are Sharp, with model numbers beginning with R-
The CPU is integrated to an LCD display, they are connected to each other
with a ribbon cable bonded to the glass and the PCB. After a while some /
most LCD segments fail to display. I suspect the problem is with the bonded
cable, but as there is no reliable means of repair (that I know) they all
get replaced.

It just occurred to me that here in the UK we use real electricity ie
230-240V, therefore the current is only half of a N American oven of the
same power. Typically the microwave side of a domestic oven here will be
protected by an 8 Amp fuse. Does this explain the anomaly?



Graham.


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