Electrolux microwave – Mbb1756S, Transformer issue?

[twicknix]

PNC 947608677

This microwave left me feeling confused, it was not powering up as dead on arrival. Found internal fuse has blown, traced to possible fault with transformer and I am confused on the connections.

One of the connector that connects from the capacitor appears to be in contact with ground. The owner says it did not trip the electrics. I carried out insulation test, it returned with high insulation reading but after I have left the address, it dawned on me that the internal fuse has blown therefore it would give false readings unless I replace the fuse.

Obviously I need to return to check again. Back to the point on the transformer, can it create earth leak from capacitor lead to transformer casing? Has it been known for this to happen?

If this diagnostic is correct, a new transformer would be required?

Thanks
Matt

[electrofix]

its a very simple circuit

disconnect high voltage wire from the transformer. put a 6.3 amp fuse in. start microwave and see if it blows. if no then transformer is probably ok

common faults are in order

shorted mag
shorted cap
shorted diode or short circuit protector

Dave

have only shown transformer secondary connections

[Author]

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