Radarange problem

[48bencix]

My 1984 Amana Radarange RR-700 stopped working, even the interior light would not work. After a little investigation on the WWW, I decided it could be the fuse. You need to remove the side of the unit, which involves the removal of tamper resistant torx screws. So I replaced the fuse and the unit lit up and seemed to work for about a minute. Then another blown fuse. More research suggests the high voltage capacitor may be the culprit. I can check that with my Heath volt/ohm meter. Any other ideas? I spoke with the salesman where the unit was purchased in 1984 (I have the bill of sale, for $328.55) he stated that it would cost a fortune to have him repair it. He said it could be the magnetron, but my research says a shorted magnetron would not blow the fuse.

Here it is with my Sunbeam Coffee Master which works but I would like a new gasket, anyone know where to get one?

Thanks,
Martin

 

[48bencix]

Interior shot

Here's the inside. Everything looks pretty good in there. Huge transformer/coil. I did take a separate photo of the schematic, for future reference.

That's a house voltage meter in the electrical wall outlet. I have had so many electrical components fail that I wondered if the voltage might be too high. It hasn't been, but I suppose a 22 year old microwave failing is not too uncommon.

 

[maytagbear]

It could be the door interlock

as well. My RR-700 had a failed fuse, and then, the interlock failed, taking the new fuse with it. The repair shop I took it to replaced the interlock and the fuse, and didn't charge for the second repair.

This was back in 1995, and it's run splendidly ever since.

Thank you for the picture of "the guts." I have always wondered what it looked like back there!

Lawrence/Maytagbear

 

[swestoyz]

Hey Martin! Lawrence is right on the money with this one - I'd check the interlocks first to see if one of them are tripping the interlock fuse board. What money you put into now is worth it the long run - keep us posted.

Ben

BTW - this was the same RR I had when growing up! Nice to see folks still using them...

 

[48bencix]

Capacitor appears to be ok

Thanks Lawerence and Ben for your advice. I pulled out the capacitor and checked it with my ohm meter, no needle movement on either terminal to ground or to both terminals, so I guess it's o.k.

I checked the interlock near the control panel, will check the other one. There doesn't appear to be a separate interlock fuse board. There is only one fuse, it goes in that fuse holder on the little red board at the lower left corner of the unit, where the power cord comes in and the white and brown wires take off. Somehow the faulty interlock can blow that fuse, a safety feature I suppose.

Martin

 

[maytagbear]

Yes!

These particular microwaves were over-engineered for safety, and I still think they are the safest microwaves ever made.

Nothing seals like a true Radarange.

Lawrence/Maytagbear

 

[48bencix]

fixed it

Thanks to Lawerence and Ben, you were correct about the interlock switch. It just needed some lubrication (WD-40 just the tiniest amount).

I need to say that if anyone is repairing a microwave oven, the high voltage capacitor can retain a charge and MUST BE DISCHARGED. Think of a T.V. where you must discharge the picture tube.

Here is a picture of the interlock switch.

 

[48bencix]

Interlock switch door open

Here's the switch with the door open, you will notice that the plunger in the lower switch rises, opening one circuit and closing another, the upper switch also opens a circuit. If any of this is not quite right, for instance, the lower switch was sticking, a circuit is completed to ground and the fuse fails.

Martin