How to perform membrane keypad repair easily?

27 Dec, 2021

By hqt

What is the membrane keypad repair?

membrane keypad repair

It is possible to repair the membrane keypad repair as explained in this article using silver ink. We will use this membrane keypad as a model, it is the brand, but this solution is made in any membrane brand.

In this post, I have put more images to be more explicit and, so that all those who want to learn, do not have any doubts when doing this. Well, we start by removing the diaphragm from the front, which we do care about, and using a blade.

Membrane panel not working

What we will do first is, remove the contact panel; we can apply a little heat with a hairdryer to remove it easily.

Lift carefully so as not to break and damage the front.

This only glue to the front mask with an adhesive that is why I explain that it is necessary to use a hair gun or heat gun, it should not get too close because it can burn or wrinkle, it is only necessary to heat so that the take-off faster and will not break.

When a membrane key does not work, the tape that connects the membrane keypad repair to the board may be bad. It happens that when the membrane has been common for a few years, it has the defect that some keys do not work. For this reason, membrane function is not activated.

The keypad of the membrane does not work keys

When they are keys like frying potatoes, cooking chicken, keeping warm, defrosting, among others, there is not much problem. It is a convenience because they save time, but on the membrane keypad, there are keys to program these actions.

Membrane keypad

The bad thing is when one of the keys that do not work is a start, clear, or clock. This defect in the membrane keypad repair has therefore that it must finish from the current to turn it off. That in case you want to finish early.

Also, when an error is made in the programming of the oven, it is necessary to disconnect because the clear is not working.

How to resort to repairing the lost functions

In older membrane ovens, like this feature 1997 LG membrane oven, it is almost impossible to get a keyboard. You must resort to repairing the lost functions in the membrane because keys do not work.

Troubleshoot or fix membrane keyboard

Below, you can see the tape that connects the membrane keypad repair with the control card. This shows the contact terminal with the carbon that covers the tracks. They are shorting or creating false pulses to the membrane control board.

two sides of the membrane keypad flexible tape

Isopropyl alcohol is common to remove dirt between the terminal contacts of the membrane keypad tape. In addition, also a napkin passes carefully so as not to remove the carbon plate from the contact.

Clean contacts on the membrane keypad tape

After cleaning so that there is no short between the conductors of the membrane keypad repair tape terminal, the conduction check. Each track on the flexible tape check for continuity.

This job will require the skill and ability of the person doing it, as the printed keypad overlay will have to lift. This is shown in the image that follows separating the two flexible sheets.

 lifting flexible PCB membrane keypad

The membrane keypad features here are very similar to PC keyboards. the contact continues between two sheets of flexible material in the form of a sandwich. This makes it difficult to repair the mic’s keypad tape tracks. These sheets separate patiently but without fear; they are glue.

membrane keypad repair 2022

Taking care not to break the sheets, they separate from each other. You can then measure the continuity between the membrane key contacts and the end of the flexible tape. When there is a continuity failure, the flexible keypad tape with a magnifying glass or magnifying glass.

Repairing Membrane Keypad with Conductive Silver Ink

The place on the membrane keypad repair tape that always breaks or opens is where its tracks meet the end of the tape that goes into the socket. That is almost impossible to repair if you don’t have silver ink to redo the bond between the carbon-plate contact and the conductive track of the tape.

The other part that suffers a lot, most of all, is close to the key contacts because they are subject to mechanical work.

The CircuitWriter, the name given to the silver conductive ink pen, reattaches the flexible tape track from the membrane keyboard. You must have a good pulse and proceed with precision. There are fine point silver ink nibs that are best for membrane keypad repair job.

Membrane keypad repair before applying clean surface

Before applying the conductive silver ink with the CircuitWriter the surface must be thoroughly clean. This is accomplished with the use of isopropyl alcohol. If you do not clean the surface well and dry, the silver ink will not stick to the flexible membrane keypad repair tape.

After applying the conductive ink, it is cover with some resin. This protects that area from future breakage problems

I finished the job on membrane keypad repair.

Once the work is completed rework with CircuitWriter and applying resin flexible tape the membrane proceeds to assemble the set. You must ensure that there are no impurities between the two flexible layers of the keypad contacts. For this reason, it is important, to avoid garbage falling in these places, not to work outdoors or with fans.

Before joining the two parts of the keyboard, make sure that all the conductors have continuity. The use of a sound continuity tester is recommended. Almost all digital multimeters have this built-in.

It is best to buy a new keypad for the membrane oven, but as I explain at the beginning, it is not always on the market. This repair of the membrane keypad repair of the membrane that I leave you applies to any other with similar characteristics.


If you don’t have the silver ink, you can tape a thin copper conductor down. You can also replace the key that does not work on the micro with a micro-switch of the kind common in other equipment.


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