Don't you miss the good ol' mechanical days when it was obvious how things worked and how things broke? Now, we have complex electronic controls for nearly every facet of life, and it's not so clear how what needs to be fixed when everyday objects stop working. In this article, we are going to examine the typical electronic oven control assembly and its two main parts: the keypad and the control board.
When either of these parts fail, similar symptoms arise, and people frequently try to fix the wrong one. So let's make the distinction between control board and keypad and then look at the three common types of control interface for a home oven.
When we say control board, we are referring to the printed circuit board (PCB) that has all the electronic components like resistors, transistors, etc. Think of it as the motherboard for a computer, although those are much more sophisticated.
When we say keypad, we are referring to the buttons on the panel that you press with your finger ('Bake', 'Broil', 'Timer', etc.) To add to the confusion, the words keypad, touchpad, control panel, and membrane switch are loosely interchanged, but all mean the same thing. Think of the keypad as the keyboard for a computer. So now let's look at three main types of keypad interface to a control board...
- Membrane Keypad
The membrane keypad tends to be in a vinyl plastic coating, inserted into the hard plastic or metal panel on the front of the oven. They tend to have tactile action, meaning you can feel the "click" of each button press. Sometimes the "click" can be pretty soft and doesn't give a great sense of confidence that you are pressing a button, especially when coupled with a failing control assembly. You are actually closing an electrical switch while your finger is pressed in on the button.
- Capacitive Touch Keypad
Capacitive touch panels are inlaid in a smooth glass surface. There are still uniquely labelled buttons for the various cooking functions, but there is no distinct tactile action for pressing any of the buttons - you just have to rest your finger on the button. The technology behind these interfaces is reacting to the slight change in electrical field introduced by the presence of your finger.
- Built-in Momentary Switch Buttons
Many control boards do not employ a separate keypad and actually have buttons mounted directly on the PCB. These control modules tend to have plastic peg actuators that reach down into the electronics to press the buttons on the board. These are the most tactile of the three types. You can really feel and even hear a solid "click" when you press these buttons. Just like the membrane switch keypads, you are closing an electrical switch when you press the button.
The membrane switch and capacitive touch panels fail all the time, but that is rarely the case for built-in buttons. Below are some common symptoms of control failure and tips for knowing when your keypad has failed vs when your control board has failed.
"Control board is unresponsive / Oven not working"
We see this problem description a lot, and it can mean a lot of different things.
- Is the display blank? If so, the board has failed and needs to be repaired. But the keypad might be bad, too - keep reading.
- Do the buttons beep when you press them? Does anything happen at all when you press buttons?
- The display is blank, and none of the buttons are working. It is "dead".
This is likely control board failure, or maybe fuse failure. It's tough to conclude this as keypad failure.
- It beeps/changes display when you press the buttons, but it still won't function properly.
So we know the keypad is still working, but the control board has failed and needs to be repaired.
- No beeping/change when you press any button, but the display is still on.
This sounds like the keypad has failed and needs to be replaced. If problems remain after that, then control board probably needs to be repaired, as well.
- None of the cooking functions work, but the timing/other functions do.
This is actually indicative of control board failure and not keypad failure, but that can certainly depend on the model of equipment.
If your symptom isn't discussed above and is more specifically related to heating issues, door lock issues, etc, then you are probably suffering from control board failure and should check out some of the other articles on our blog.
As you can see, it's tricky to know when the control board has failed vs. when the keypad has failed vs when both have failed (unfortunately, it is not uncommon for both to fail at the same time). If you're not sure, the best thing is to contact us with a detailed description of your symptoms and a control expert will help you figure out the correct course of action.
If you've determined that the control board has failed, then you've already come to the right place! ApplianceBoardRepair.com specializes in repairing control boards. Search for your part/model in our database and place a repair service order, or contact us if your equipment is not listed.
If you've determined that the keypad has failed, then it needs to be replaced. The construction of keypads does not allow for them to be taken apart, fixed, and put back together in a reliable way. If you know your model number, you can search if on popular appliance parts retail sites to see if they have the keypad (aka control panel, touchpad, etc.) in stock. Or, you can at least find out the part number for your keypad and then do some general internet searching. You can often find appliance parts for sale on 3rd party sites like eBay. Always be careful when buying from 3rd party sellers - make sure you can return potentially defective parts for full money back.
Lastly, if you need a new keypad but it's no longer stocked or being sold anywhere, we can still help. Our engineers have developed new technology for this exact scenario which enables you to control the oven from a 7" Android tablet (included) over a wireless Bluetooth link - the LinkBox. Contact us for more information.
KEY THINGS TO COVER:
- How to know when your oven has a membrane keypad
- How to know when your oven has a capacitive touch keypad
- How to know when your oven has momentary switch interface buttons on the control module
- How to distinguish control board failure vs keypad failure (it's common for both to fail simultaneously)
- How to look up your keypad part number
- What to do when your keypad is NLA (LinkBox baby!)