Re: Duff microwave oven (2024 Update)

[Mr Pounder]

[meow2222]

The HV rectifier. It may just be the fuse though, 2A and under tend to self blow in time.

NT

[Andrew Gabriel]

A shorted HV rectifier or shorted HV capacitor would blow it.

Also, if the magnetron has somehow suffered a catastrophic internal failure, it might end up with the anode and cathode shorted, but that seems unlikely.

[ARW]

[Harry Bloomfield]

Where microwaves are concerned, replacing the fuse is the quick simple diagnostic job. It will probably be on the low voltage sde, not the HV.

Other options are replacing the transformer or the magnetron, if there is definately no heating effect.

[Harry Bloomfield]

ARW expressed precisely :

You cannot really test them properly, without the test voltage needed for the test - just put another fuse in.

[ARW]

[Harry Bloomfield]

Ouch - very unusual..

They usually only protect the input to the transformer, where the current is more sensible for fuse ratings.

[ARW]

[Andrew Gabriel]

I think the HV side is always protected, and it has to be very closely fused too because the transformer can't generate much extra in the way of a fault current.

[meow2222]

Simple, short the dead fuse & plug in. Nuke HV fuses just protect against fire risk from prolonged overrunning of the transformer. Testing it for a minute won't get it anywhere near hot enough. And millions of nukes have no such fuse too. If its ok with no fuse, fit one and its done.

NT

[Geo]

Maybe these days - but not in our old clunker - circuit diagram:-

Does the magnetic shunt not act to limit current?

[Gazz]

[ARW]

[meow2222]

Always test fuses before fitting :)