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Sharp r-21 atp runs and seems to work as normal but no heat at all.

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If, when you hit Start, the fan comes on, you either have a bad relay (RY2) or a bad latch switch (the bottom, outside switch) or a failed part in the high voltage section, most likely a bad connection at the FA terminal of the magnetron, or a bad magnetron itself.

If, when you hit Start, the fan does not come on, you have a bad 1st interlock switch (the top switch).

We have the service manual for the similar model R-21AT and have uploaded it to our site here to help you.

You will need the
free Acrobat Reader to view or print it in case you don't have it already.

Please note that some parts for this model are not the same as for your variant, so please contact the distributor (below) for the proper part number.

The best place to order Sharp parts is Tritronics. You can also call them at 866-779-5835.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

Posted on Nov 27, 2008


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I've uploaded two versions of them here and here.

Hope this helps.

We're happy to help and we appreciate your thoughtful rating of our answer.

William E. Miller, AS-EET

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