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Damper motor runs all the time even when oven is off

The microwave portion of this microconvection oven was run for about two minutes with one of those round foil containers that some Italian restaurants give you with leftovers, including the lid which it turns out has foil on the inside of what looks like a cardboard lid. After this stupid move and discovering the meal wasn't heated, I also discovered there was the constant sound of a motor running even with the unit turned off, though it was obviously still plugged in. The microwave still appears to heat a cup of water but I did not test it for very long. I have not chanced testing the convection oven function. After disassebling the oven I found that the source of the noise is the damper motor and the dampers were found to be in the closed position. If I manually open them with the unit on, the damper motor stops running when the dampers are open and then starts to run again when I close them, which I assume is due to a microswitch, though I didn't actually see one. I took the motor out and bench tested it. The motor shaft turns, and it will reverse after it moves the arm a certain distance once power is cut to it and then restored. If I apply resistance in the form of a finger to the arm on the shaft (this arm connects it to the outlet damper) I do not feel much force and the motor shaft will continue to turn while the arm is held stationary, which is apparently what I was hearing from the oven, i.e. the motor is not moving the dampers. Is this merely that this motor needs replacing or is there something else that is possibly wrong with it? As noted above the motor appears to reverse after power is stopped and restarted if the arm is in a certain position so I wonder if it could somehow have been trying to close an already closed damper instead of opening it. GE model number is JVM1490B003. Thanks.

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  • bgoldfarb Dec 31, 2008

    I replaced the entire intake damper assembly which includes both the damper motor and damper switch in addition to the intake damper itself as this is how GE packeages this part. The switch appeared to check out okay and I had found the damper motor alone for sale on the web but it was not worth the price difference. Normal function of the damper is closed in convection mode and open in microwave mode. Now if I could just stop the handles from breaking. As stated many time elsewhere, they are a poorly designed piece of **** on an expensive oven.

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  • 8,820 Answers

Sorry for not getting to this sooner.

If you can stop the motor with just a finger, it is bad.

You can usually find helpful exploded view diagrams and order parts by entering your full model number here.

You should check the damper switch as well, especially if the motor has been "running" more than it's supposed to.

There should be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.

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 Have a sharp microwave model # R1874. On the control panel, when I press the start button, the microwave runs for 59 seconds then stops. I have to press the start button again to have it run again. It...


That would be a problem in the damper assembly, either a bad switch or motor, or the damper door is jammed or blocked. Consult the attached diagram for general reference. The damper switch is the same as the primary interlock (door) switch.

zjlimited_813.jpg

Its location varies by model, but you'll have to take the outer cover off to find it.

The best place to order Sharp parts is Tritronics or you can call them toll-free at 866-779-5835.

If you only need a switch, you can order a universal type HERE

Also, I quote other similar solution...
I had the same problem. Turned out to be the micro switch and damper motor. I replaced both myself and fixed the problem for less than $40.00. The best advice I got was replace the switch, reconnect the motor and make sure the motor runs through a damper door cycle. It didn't run, even though it showed continuity and had power, so I replaced the motor which solved the problem. The micro switch which is activated by the cam on the damper motor has to be cycled within one minute, or the unit shuts itself off. The damper motor on my model R-1870 is found in the right rear section of the assembly when facing it. You have to remove the unit, and remove the outer casing to get to it. The damper is a simple sheet metal door, activated by the motor, and the switch mounts at the top of the motor and is activated by the same cam that activates the door.


Good luck.

Mar 06, 2011 | Sharp R-1874 Convection/Microwave Oven

1 Answer

The microwave stops itself everytime at 59 secs if put on for any time over a minute


Change the damper motor and switch. Cost for both approx. $30.00. Must remove cover to gain access to motor & switch.
ZephyrKnight

Feb 17, 2011 | Sharp Microwave Oven Microwave Oven

1 Answer

Why does the microwave only run for 1 minute at a time on any setting?


This is a problem in one of the damper-related components, either the switch or motor or the damper door may be binding.

The damper is a door inside that opens or closes depending on cooking mode. If the controller senses that the door is not in the right position, it will shut down the cook cycle.

Sharp models stop after 59 seconds.

See the attached sample drawing for a typical damper assembly.

We have the applicable service manuals for these models and have uploaded them to our site here
and here
to help you.

If a switch is all you need, we offer a universal type for only $5 postpaid which you can order here.

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

b27054b.jpg

Dec 31, 2010 | Sharp R-1874 Convection/Microwave Oven

1 Answer

Sharp convection microwave R-1870 runs about one minute and shuts off. damper Motor switch?


This is a problem in one of the damper-related components, either the switch or motor or the damper door may be binding.

The damper is a door inside that opens or closes depending on cooking mode. If the controller senses that the door is not in the right position, it will shut down the cook cycle.

Sharp models stop after 59 seconds.

See the attached sample drawing for a typical damper assembly.

We have the applicable service manuals for these models and have uploaded it to our site here and here to help you.

If a switch is all you need, we offer a universal type for only $5 postpaid which you can order here.

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

Dec 17, 2010 | Sharp R-1870 Convection/Microwave Oven

1 Answer

The microwave will run for a minute and then shut off


This is a problem in one of the damper-related components, either the switch or motor or the damper door may be binding.

The damper is a door inside that opens or closes depending on cooking mode. If the controller senses that the door is not in the right position, it will shut down the cook cycle.

Sharp (and Sharp-made Dacor and Wolf) models stop after 59 seconds.

See: http://www.fixya.com/uploads/Howto/B27054B.jpg

Nov 29, 2010 | Dacor DMT2420SS Microwave Oven

1 Answer

No matter what time i put in it cuts off in 60 seconds on a sharp


This sounds like a bad damper switch or motor. Double check the shut off time....... see if it's actually 59 seconds..
When you unplug the unit from the wall for 2 minutes then plug it bad in, you should be able to faintly hear a motor run for a few seconds. This is the damper motor running. This will verify that the motor is operating.....
Also, check the thermistor.

Sep 08, 2009 | Sharp R-1870 Convection/Microwave Oven

1 Answer

Sharp Covection Oven/Microwave stops after 1min on any setting


This 59-second stop failure is due to a problem in one of the damper-related components, most likely the switch, but it may also be the motor or the damper door.

The damper is a door inside that opens or closes depending on cooking mode. If the controller thinks that the door is not in the right position, it will shut down the cook cycle.

See the attached sample photo.

If you or someone you know wants to look into this, we have *critical* safety, disassembly, and troubleshooting info at our site, and our link is at our listing here on FixYa: http://tinyurl.com/yzjozk

We even have a video on our site that shows you how to safely & easily remove the control panel assembly to send it for service.

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

db711c4.jpg

May 08, 2008 | Sharp R-963 Convection/Microwave Oven

4 Answers

Sharp R-1874 shuts off after 59 seconds


I had the same problem. Turned out to be the micro switch and damper motor. I replaced both myself and fixed the problem for less than $40.00. The best advice I got was replace the switch, reconnect the motor and make sure the motor runs through a damper door cycle. It didn't run, even though it showed continuity and had power, so I replaced the motor which solved the problem. The micro switch which is activated by the cam on the damper motor has to be cycled within one minute, or the unit shuts itself off. The damper motor on my model R-1870 is found in the right rear section of the assembly when facing it. You have to remove the unit, and remove the outer casing to get to it. The damper is a simple sheet metal door, activated by the motor, and the switch mounts at the top of the motor and is activated by the same cam that activates the door.

Oct 24, 2007 | Sharp R-1874 Convection/Microwave Oven

2 Answers

Clock will run down to 1 second of the minute and microwave will stop


The surge probably didn't cause this. This common error indicates a problem in the convection damper circuit. It may be a defective damper switch, damper motor, or a jammed damper door. I have attached a drawing of a typical damper system. If you or a friend decide to work on it, we have *critical* safety, disassembly, and troubleshooting info at our site, which is linked at our listing here on FixYa: http://tinyurl.com/yzjozk You can order parts for Sharp models from Tritronics at http://www.wehaveparts.com.

Sep 21, 2007 | Dacor PCOR30 Convection/Microwave Oven

1 Answer

Timer problems


You probably have a bad damper switch, damper motor or damper. See the attached sample drawing. You can order parts for Sharp models from Tritronics at http://www.wehaveparts.com.

Sep 16, 2007 | Sharp R-765 900 Watts Microwave Oven

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