Sharp Microwave Oven R-1874 Circa 2004 removal

MrTransistor · 02-17-2010, 04:32 PM

Sharp Microwave Oven R-1874 Circa 2004 removal.

If you ever have a problem with your Sharp Microwave Oven R-1874 Circa 2004 and others, wherein it shuts off after 59 seconds, here’s the fix. The problem is caused by either a defective Damper Door Motor or the Micro Switch that is associated with it. Here is how to replace the motor. The Damper Motor used on the R1874 is P.N. RMOTDA256WRZZ. The switch is P.N. QSWMA085WRE0. The Turntable Motor is P.N. RMOTDA252WRZZ. And the Turntable Support is P.N. FROLPB027MRK0. It has three arms and three wheels. Parts ordered from www.searspartsdirect.com

I just posted pictures with instructions. Here is an example picture, the sequence is 18 pictures if you need them and the irv2 posting gets the order wrong but they are numbered for the right order.

DriVer · 02-20-2010, 07:53 AM

Quote:

Originally Posted by MrTransistor

Sharp Microwave Oven R-1874 Circa 2004 removal. I just posted pictures with instructions. Here is an example picture, the sequence is 18 pictures if you need them and the iRV2 posting gets the order wrong but they are numbered for the right order.

Thanks for the article MrTransistor. Perhaps I'm missing something but would you have a link to the other pictures in this collection? Thanks!

MrTransistor · 02-20-2010, 02:31 PM

Sorry Driver,

Should have made it a little clearer that the postings were on this web site in the photo section under MrTransistor. Here is a direct link, hope this helps someone.

MrTransistor Gallery - iRV2.com RV Photo Gallery

wagonmaster2 · 02-21-2010, 11:31 PM

Mark-

I have the Sharp R1870 in my 2004 Itasca Meridian and am going to have to replace the damper motor and switch to eliminate the 59 second shut-off. Will probably replace the turntable motor at the same time.

All your pictures were very impressive and informative. Can you tell me the best order for removing the holding bolts/screws? On mine there are several screws along the upper rear part of the oven, two bolts straight down from the top just under the shelf board on top of the oven, the two long angled bolts on each side accessible through the filter openings, and then several screws along the underneath side at the back of the oven. I haven't been able to tell which ones to start with first and which ones to be left till the very last when it will start dropping.

Thanks for being there with all your help for us novices. Nothing works like previous experience.

Wagonmaster2
2004 Meridian 36G

MrTransistor · 02-22-2010, 03:18 PM

Hello Wagonmaster2,

Similar mounting scheme for a different coach. I just reviewed the parts breakdown for your coach and my recommendation is to start with the two or three screws that hold the unit at the bottom rear. Next, unscrew the two long anchor bolts located under the filters. Then, after supporting the microwave, remove the screws at the top of the front bracket allowing the microwave to tip forward and down hinging on the rear bottom lip. No need to unscrew the small L bracket that is attached to the underside of the cabinet. See http://www.winnebagoind.com/service/...04/4ikp36g.pdf page 14 item 2 (PDF page numbers).

The pictures in the photo section are titled in correct order but displayed out of order. When I posted them, they were in order but when it was all done, they got scrambled i.e. the site software placed pictures 17 & 18 in front of 15 & 16 and 2 & 3 ahead of 4 & 1. Roll your curser over each image and the name with number will be displayed. Perhaps the web-master can look into this.

The first four images show the Turn Table motor, and image 18 is just the schematic. If you view the other images, there will be a description of what’s going on under the image. Download all the images and let your explorer sort them into proper order. Then look through them in order and it may make more sense. The descriptions should help a lot.

Let me know if there are any other specifics I can help with. Are you going to order through www.searspartsdirect.com ? I found them to be quite reasonable on price, easy to use, and fairly expeditious on delivery. I know the switch is cheap but you could save a little money by just cleaning the contacts. It comes apart way too easily. In fact it may fall apart as you remove it if you are not careful. The contacts pop out and can be rubbed against a paper towel laid on the edge of a table. Makes more sense when you see it.

The parts list shows a Sharp R-1875 installed in your coach. I think all of these units are essentially the same: the R-1870, R-1874, and the R-1875. I may look into the differences.

wagonmaster2 · 02-23-2010, 08:01 PM

Hi Mark -

Appreciate the removal explanation, it's always great to have the experience of someone who has done a project and knowing the best sequence of events.

I ordered the damper motor from Encompass last fall and never pulled the oven while we were using it and now decided to go ahead and get the turntable motor to have it replaced at the same time. The back yard where the MH is parked has been so messy with all the rain and snow I'm waiting for things to clear up before having the Tech come out to get the oven (and help me remove it as I have to much back trouble to try it by myself).

Before I ordered the TT motor I was reading about problems people were having with Encompass since they ship from Baldwin Electronics in Florida, which don't appear to be very customer oriented. I had received the TT motor from AMI Resources before you suggested Sears, and its amazing how many different parts numbers there are for this motor. AMI shipped a motor no. RMOTDA211WREO, which is the same number Sears listed when I put in my oven Model No. (and cheaper than AMI - I'll know better next time), but when I put in a part no. search for 252WRZZ at Sears I got a substitute No. 264WRZZ. Partstore.com also listed 264WRZZ for my oven. I called the lady at AMI who took my original order and asked how or why there were several numbers for the same part for the same oven. She kind of laughed and said she was doing a little research on this very matter and had discovered 14 different part numbers for this same motor depending on who manufactured it, where it was actually used and which make/model it was used in. I know the Sharp Model 1870, 1874, etc are all the same oven, just either black or chrome finish but they must list different part numbers for the same part.
I sure hope when mine is removed it will be the same as the one I received.

Thanks again for all the great help, I don't know if the Tech has removed any of these ovens before but he says he works on lots of different types of microwaves. He's worked on my TVs for years and is very trustworthy and knowledgable so I trust whatever he says.

Wagonmaster2

jimmccreary · 03-02-2010, 02:37 PM

Mr. Transistor,
Beautiful detail on microwave removal. I wish I had seen your photos before I removed my microwave and replaced the damper motor.
jim & Debbie and 2 cocker spaniels
04 Journey C7 34H + Suzuki SX4 AWD toad

JBroadaway · 03-25-2010, 01:26 PM

2005 Itasca Meridian. I'm having a problem with the microwave. Everything works fine except when I try to heat something using microwave. The lights are on, the fans work, the convection oven works, but the microwave doesn't. Here's the bigger problem; I have had it removed twice, taken to a Sharp Service Center in Phoenix, and it works just fine sitting on their bench! Re-install it in the motor home and it doesn't work!! I've checked the plug and it is fine. This has been going on for a month; we haven't moved from our original site so travel isn't the problem. I went to the shop yesterday, put a cup of water in it, and it worked just fine. They re-installed it in the motor home this morning and it doesn't work!!! Going nuts; can anybody help?????

TN Bill · 03-25-2010, 01:58 PM

You might try these people. all Microwave Display Repair Sharp Dacor GE General Electric

They fixed my microwave control panel and I did not have to remove the unit from the RV. Got instructions for removing the control panel only.

JBroadaway · 03-25-2010, 04:12 PM

TN Bill, Thanks for the info; good website. Problem is both appliance repairmen have said they checked the control panel and found no problems. You would think they know what they are doing but the darn thing still doesn't work.

MrTransistor · 03-26-2010, 04:03 AM

Hi Broadaway,

Intriguing. Best guess would be that the outlet for the microwave is wired wrong, i.e. the neutral is connected to the hot blade and vice versa. That’s the best I can think of for working at the shop and not in the RV. Using a meter, measure the voltage between the large blade (neutral) of the outlet and the round ground pin. If you read less than 1 Volt, it should be wired correctly. But if you read 120 Volts, it is definitely wired wrong. This should be easy to correct.

Now the other issue would be an open ground. This is usually seen as a voltage higher than 1 Volt between neutral and ground. If you suspect a problem, you’ll need to ohm out the ground wire. Using longer meter leads if required, ohm between the ground of the microwave outlet and the ground of an outlet on the opposite wall. Real world readings will probably be around 1 or 2 ohms. If it’s open or has a high reading then it must be corrected. Good luck!

JBroadaway · 03-26-2010, 11:45 AM

I have actually plugged the microwave into a different plug with the same results. Also, everything works except the microwave portion; convection, fans, lights, clock, etc. The microwave has worked fine for almost two years since I bought the rv and has just started giving me problems the past few months.

MrTransistor · 03-26-2010, 12:51 PM

The ghost of Christmas past? What voltage do you read ‘at the plug’ when you: turn on the microwave, use the convection oven, and in standby. If you had an O-Scope, I would be curious as to what happens to the sine wave under these conditions also. Something has changed, probably not intentional, that is affecting your RV’s outlets or possibly the whole park or house or wherever you are parked. To see if it’s internal to your RV, try running a heavy extension cord to the pedestal to connect directly bypassing the coaches wiring. Let us know what you find.

wagonmaster2 · 03-26-2010, 01:46 PM

Quote:

Originally Posted by JBroadaway

I have actually plugged the microwave into a different plug with the same results. Also, everything works except the microwave portion; convection, fans, lights, clock, etc. The microwave has worked fine for almost two years since I bought the rv and has just started giving me problems the past few months.

Undoubtedly these Sharp microwave ovens must really be dogs. I've read about so many problems with them on the Forums, along with my problem of it only running 58 seconds before shutting off. Guess that's better than not working at all though.

Wagonmaster2

MrTransistor · 03-27-2010, 06:45 AM

Hi Wagonmaster.

The damper motor should cure your 58 second problem, it cured mine. I have read that Sharp designs and builds these microwave ovens to make it to the end of warranty and no further. I guess they figure that the savings on manufacturing costs more than covers the occasional warranty repair cost. Plus, they get to sell you a new one every two or three years. As they say, ‘They don’t build em like they used to’.

wagonmaster2 · 03-27-2010, 11:55 AM

Mr Transistor-

Ain't that the truth though. I guess that's what they call built in obsolescence. I've had the parts to fix my Sharp since last summer but hate the thought of trying to get that heavy thing down and out of the coach, then back in again. Have an independent repairman who'll come out to the house and help me get it out and replace the parts but between using the coach last fall and the weather being so bad with a soggy yard I've kept putting off having someone running in/out of the coach. Being able to still use the oven by keep hitting the Start button hasn't helped my procrastination any either. Needing new tires, got the new Bell Crank to have installed, got a valve adjustment coming up very soon, and trying to get a new roof installed on the stick house before the insurance time runs out. Things can sure pile up all at once.

Wagonmaster2

JBroadaway · 03-27-2010, 12:12 PM

The mystery continues..............I tried a few things this morning and here are the results.

Ran a heavy duty extension cord to the shore power 110 outlet direct to the microwave. Microwave didn't work.

Disconnected shore power, started generator.

1st time. Pulled 15 amps and microwave worked; water very hot.
2nd time, Pulled 7 amps; didn't work;water cold
3rd time, Pulled 6 amps; didn't work;water cold

Put motor home back on shore power.

1st time. Pulled 4 volts and microwave worked; water very hot.
2nd time. Pulled 1 volt; didn't work;water cold
3rd time. Pulled 0 volts; didn't work;water cold

Waited 10 minutes, still on shore power, tried again
1st time. Pulled 1 volt; didn't work; water cold
2nd time. Pulled 1 volt; didn't work;water cold

Disconnected shore power; started generator.
1st time. Pulled 6 amps, 1volt; didn't work; water cold

Back on shore power.

1st time. Pulled 1 volt; didn't work;water cold

Used 2 minute intervals each try.

I am now convinced that there is something wrong internally with the microwave and that coach wiring is fine. Any suggestions???

MrTransistor · 03-27-2010, 07:42 PM

Sounds like it’s time to replace the Magnetron. Seems like a big deal but the cost isn’t too bad. As the filaments age, they can no longer emit sufficient electrons for the tube to oscillate. Depending on how high the line voltage is and whether the filaments were hot to start with will determine if it can start oscillations. Once it starts, the current emitted by the filament will supply extra heat and keep it going.

http://www.searspartsdirect.com/

http://www.searspartsdirect.com/part...ken=partSearch

Magnetron
Number: RV-MZA331WRZZ
Component: Oven/Cabinet Parts
Size: 8.20L x 6.50W x 5.80H
Price: $62.99

bjsheldon · 06-05-2010, 09:46 AM

Mr Transister:
I also have the 59 sec problem and am trying to remove the microwave to check out the damper motor and switch.
Problem is I can't get the microwave out. I have removed the series of screws along the top and on mine there are 3 screws on the bottom that hold the rear in place. I can wiggle the unit, but it will not come out. Acts like there are additional screws somewhere in the back.
ANY SUGGESTIONS? I sure would appreciate any help.
John

wagonmaster2 · 06-05-2010, 09:37 PM

Quote:

Originally Posted by bjsheldon

Mr Transister:
I also have the 59 sec problem and am trying to remove the microwave to check out the damper motor and switch.
Problem is I can't get the microwave out. I have removed the series of screws along the top and on mine there are 3 screws on the bottom that hold the rear in place. I can wiggle the unit, but it will not come out. Acts like there are additional screws somewhere in the back.
ANY SUGGESTIONS? I sure would appreciate any help.
John

John - I've had the same problem with my Sharp 1870 microwave/convection for about a year now and have the motor/switch in hand but haven't got anyone to help me lift that heavy thing out yet. An independent repairman has agreed to do all the work but he also runs a lake side supply store in the summer so am having a hard time arranging my schedule with his. I also decided to order the turntable motor to replace it while its in the shop. Removing it once will certainly be enough.

Sounds like you have most of the attachment screws removed except (if yours attaches like mine) the two long bolts that are accessible through the two filter openings. Those are the ones that have me concerned since one of them isn't visible where it screws into. How hard is it going to be to get it replaced after the oven repair job?

Wagonmaster2
2004 Meridian 36G