Need repair part for microwave

We have an over-the-oven microwave that recently broke. It still cooks but recently started buzzing when the door is closed. After looking into it, it seems that the controller board might be broken or possibly the switch because that buzzing is the magnetron kicking on. I confirmed this by placing a bowl of cold water in it and closing the door. It gets hot after about a minute. Does this assessment sound correct? For now we just plug in when when we need to use it and keep it unplugged. Now I need to find a part to fix it because it is out of warranty but I don't know where to look, nor do I know what the correct part would be. Any advice would be appreciated.

 

If the magnetron starts operation when closing the door then you probably have a burned (stuck closed) relay on the control board.

A make and model would be required for further assistance.

 

I looked up the model and everything to include it in my message but I was doing too many things at once and overlooked that crucial detail. It is a Samsung SMH1713S. Thanks.

 

I found the service manual but I am still uncertain what part is the issue.

 

You found the service manual or the owners manual ?
The owners manual will not give you any usable help in this repair.

I haven't serviced this model of microwave but I was reading on a repair site that the door micro switches are the problem. I disagree. If you open the door and the microwave stops.... the switches are working. I still believe it's a control board problem.

Some microwaves use a separate control module for the microwave operation but I don't see one listed for yours.

In the link below... the pictorial part you are looking at is #3. The board is pretty inexpensive and if you get it from a place link in the link.... you can return it if it isn't the problem.

Parts for Samsung SMH1713S/XAA-0001/Control Parts - Appliance Parts Pros

They may require the FULL model number for the order.

 

It's the service manual. I wanted a layout of the PCB and wiring diagram. I also saw I couple forums about the issue with other models and the main consensus was that the control board was bad/maybe the switch. I have pretty good experience repairing electronics in general, stereos, TVs, motherboard, etc. Just never a microwave. It didn't sound to me like a switch issue either but I wanted a more experienced opinion. Thanks for the link. I was looking for that part but, again, I don't have enough experience with certain appliances to know where to look or know common nomenclature.

One last question that I'm pretty sure I know the answer to but thought I'd ask anyway. If possible, I typically replace the broken components rather that the whole board because sometimes components break because the component itself is faulty and other times it's some other fault in the board causing a component to break and since I can get the component for a few cents or dollars I will usually try that first and if it breaks again, replace the board. My wife now informs me that she also thinks the microwave is only working on high. To me this sounds more like the entire board may be bad rather than just one component. Does that sound accurate or would /could a broken relay cause both issues? And would it be worth it to try and replace just the component?

 

There is no actual temperature adjustment on a microwave. It's duty cycle.
High would be magnetron on 100% of the time.
Medium could be magnetron on 50% of the time.

So... if the relay that controls the microwave section is the defective one.... she's right since the relay can't open.

If you want to troubleshoot the board..... let's go.

I need a picture of the front and back of the board as well as a copy of the schematic. They need to be big and clean. You can send them to me and I'll host them as they are no use posted here on the board due to compression. I sent a PM to you with my email address for the pictures.