Something else that just came to me. Would this tear NOT have happened if I had not taken out the 2 backing layers (the thick and the thin layers that were behind this layer as reinforcement) or at least left one one them there? I think likely. So not only was taking those layers unnecessary but it also contributed or caused this tear.

Please let's hear your opinion on why this tear happened and at least for the sake of others how to prevent it. Thanks.

 

Or a new keypad.

I can't find any new keypads, if anyone know where to get them please post the link.
Make and model: Whirlpool Double Oven RBD305PDB12
Here is a link to a new one which is no longer available:
https://www.easyapplianceparts.com/...305PDB12&ModelNum=RBD305PDB12&ModelID=7606844
Even if it was available it would be out of the budget for this repair.

Yes, keep the other layers on.

Yes that would likely be less prone to causing a breakage like happen to this membrane.

Why did you put it in the freezer?

You recommended that for "stubborn" ones that don't come apart easily you put the board in the freezer. Obviously you did not fathom that with the 2 backing layers removed a trip to the freezer can make the thin layer of plastic remaining fragile enough for it to break. Of course this is hard to foresee unless one has experienced it before.

I having had no experience in this regard thought putting it in the freezer is a safe bet. I could not foresee this eventuality. In retrospect I should have first tried to see "how stubborn" it was before trying the freezer. But as mentioned above I did not think that putting it in the freezer would have any negative consequences. I was probably wrong especially since the 2 backing layers had been removed and what was left was a very thin layer.

Even if it had not torn the repair would have been about the same. The ribbon is insulated till it goes to the membrane and there is really no access to repair the ribbon's trace. I will try to show this with pictures later. As I mentioned previously I do not think that the repair would have been much different had it not torn, in fact it might have even been more difficult depending on the amount of damage the other portions would have experienced during he layers separation.

Still the same issues would be there: ribbon's trace not being available for repair, how to repair the torn out traces and the job of re gluing what type of glue would work. These are the same issues this repair is facing with or without a tear.

Here is the way I am contemplating continuing this repair.
The ribbon has 2 ends, one end goes into the plug on the pcb and is blackened and is conductive. The other end of the ribbon goes into the membrane. In between these 2 ends the ribbon is insulated inside plastic.
The conductive trace inside this plastic insulation is so thin that it is NOT possible to expose it. So in order to connect the ribbon to the keyboard membrane traces conductive material from the blackened end of the ribbon has to be brought into the traces of the membrane as shown below.
https://drive.google.com/file/d/13Mph3Nx1lab8Rw7HO-QqAKcS-lriYdlz/view?usp=sharing

In order to the joining of the membrane traces to the conductive material brought from the plug end of the ribbon, the traces need to be exposed then conductive glue can be used. The tear did most of the exposing but there is still a portion that needs to be exposed as shown in the pictures below.
https://drive.google.com/file/d/1Teh1iLgAEvt8s3RPBEMO-NcFMjBfab3-/view?usp=sharing
https://drive.google.com/file/d/1C8DSbHq9IvIRIGsaxfqdYSrhtXS3s6Hr/view?usp=sharing

Once the repair to the traces are done and the layers are protected by the glued outside layers it should be a good repair.

Questions that need to be answered:
What kind of conductive material is suitable to bring the ribbon's blackened end into the membrane traces?
What kind of conductive glue is good to then connect these 2 traces together?
What PSA can be used for the final assembly?

Please share you thoughts. Thanks.

​

 

Another workable idea: solder a 12 pin female connector to the pcb directly bypassing the ribbon and its connector altogether. Then run the male portion of the connector with a 12 conductor flat cable to the membrane traces, glue the wires of the flat conductor to the traces using conductive glue, test everything and cover this repair with some material like epoxy glue.
https://drive.google.com/file/d/1LntimpPkQYfMtccQtl_W00iphbkqIOvY/view?usp=sharing

This won't interfere with the pads for the oven's buttons.
After testing for functionality cover with epoxy or some other material for strength.
Glue the 2 protective layers back on and put back into operation.

Please see the picture below.
https://drive.google.com/file/d/1X-GjzgFB_TSQHVtqKsgi9_l4_jY5rGVD/view?usp=sharing

Please share your thoughts. Do you approve of this idea? Any downside

 

Usually it is isolated by the same center layer. Yours is isolated by what?

The membrane electrical layer construction is as follows:

• the outer layer with the name of each button which is what the operator sees
• behind the outer layer is the vertically printed pad layer (this layer does NOT have any traces going to it directly, it simply acts as a bridge for the other printed layer acting as the on/off button)
• the insulating layer (this layer acts as the air gap allowing the vertically printed and horizontally printed layers to be separated from each other until the operator pushes on the oven's button)
• the horizontally printed pad layer (this layer has all the silver traces going to it, it is the heart of the membrane electrical layer, each horizontally printed pad has a gap which is bridged when the vertically printed pad is pushed on, this completes the circuit allowing electricity to flow)

Please see the following pictures to visually see the layers described above:
https://drive.google.com/file/d/1U-ZPQc9GvbxKyuRyi3ZLQlUszXzyoOsH/view?usp=sharing
https://drive.google.com/file/d/1RxU2wg94HWDvDd-LS27GZmKYk8K32DMA/view?usp=sharing
https://drive.google.com/file/d/1oXWBfbJbQOND3OZPJxuNlO86RPNQM6kg/view?usp=sharing

The electrical layer of the membrane has 2 electrical traces; one is silver in color, the other is brown. I have not as of now figured out the relationship between these 2 traces so please share your thoughts. Thanks.

I think it was you that posted a link in a previous post where you could get one. There is many places that will gladly get one to you.

I did post a link to a place that USED to carry them, but they are no longer available.

What is your budget this repair exactly?

There is no fixed budget, but the lower the better.

Yours seams fairly easy to separate, given you use the right tools.

I bought a brand new Excel K1 knife

And your use of a feeler gauge. What thickness are you using?

I did NOT use the feeler gauge for this electrical layer.
I took the membrane out of the freezer, then used the brand new knife to go over the extreme edges making sure the knife does not touch any traces. Then I used hands to gently pry the two layers apart. As I was praying the 2 layers apart I noticed that a lot of traces were being broken and coming off either on the side being pryed or being left on the other side.
In retrospect I should have stopped at this point and possibly abandon the idea of separating the electrical layer altogether, if I had, perhaps the idea of soldering directly to the board and bypassing the ribbon could have been accomplished somewhat easier. But I did not have the knowledge that I have now about the construction of this membrane so probably could not come up with that idea.

As I continued to pry the 2 layers apart being very careful not to put too much force and just enough to separate them, suddenly the layers gave way. Like a vacuum was hit. I found the membrane torn as was described earlier. Had the membrane not torn at this stage only more damage would have been inflicted on the other side of the membrane as the praying was taking place, so in a way it was a lucky break.

I did not know it at the time because I did not know how this membrane was constructed, but a big chunk of the insulating layer was coming off with the layer that is at the back of the electrical sandwich layer (before the 2 thicker protective layers which I had already removed using the feeler gauge method).

The insulating layer is totally fused to the other layers.
It is not possible to separate it from the other layers. Trying to separate it from the other layers only make it be shaved off but not separate. Perhaps this it the ultrasonically fused type you mentioned, if it is, then the entire layer is fused not just a few cross hatched areas of it.

The insulating layer and the backing layer where they came off together were completely fused as shown below.
https://drive.google.com/file/d/1BmpFQ0B2RMD4iguBg4KXNBonAT_mSswY/view?usp=sharing

In other words a fifteen minutes easy repair transforms into a three hours nightmare.

At this point I would consider this a successful repair with adequate result if this membrane is fixed. When tackling anything especially for the first time the likelihood of running into issues is high.

 

So how much different types of "glues" will this repair need?

If I have to try the idea of soldering directly to the board bypassing the ribbon, the type of glues needed would be:

• Conductive glue to connect the wires coming from the board to the traces of the membrane. Also use this glue to fix the broken traces on the membrane.
• A stronger glue that goes over the conductive glue to makes sure the conductive glue stays where it is put and to act as an insulation
• Pressure Sensitive Adhesive PSA to glue back the torn portion and the backing layers

 

At this point your best bet would be to use a Cir-Kit frame.

I checked Cir-Kit frame. Prices on the websites I checked were over $200. Unfortunately that is beyond the budget for this job.

Regular PSA.

Are you saying that the layer I have called the insulating layer is Pressure Sensitive Adhesive (PSA)? If so it is used to insulate the brown traces from the silver traces. It also clearly feels like plastic with no adhesive quality on my fingers. So I still think this is the insulating material and not adhesive.

Silver=backside, brown=frontside, you probably also have black contacts.

Silver trace is the main trace of the membrane. It connects the pads together and also to the ribbon.
The brown traces are jumpers where 2 silver traces needed to be connected but a third silver trace would short out if the other 2 were connected directly.
So the brown trace which is insulated from the silver trace except at the dots, is used to accomplish this jumping.
At the dots the brown trace connects the two intended silver traces together.
See the picture below to see this visually on the membrane.
https://drive.google.com/file/d/1CNtJXBOuwXDxXVjUdI8Cr4HvH_cRUc5q/view?usp=sharing

https://www.fixyourboard.com/ledgestone.html

This website only lists the board. I entered the numbers for this make model etc and it stated the board is not available.

You are escalating cost, a new keypad would probably be more cost effective.

As stated previously I tried to find the board but except used ones it is not available. Used ones costing around $200 are beyond the budget for this job.

Useless, a copy of a regular X-Acto.

I thought since this was made in USA it would be better than the X-Acto. If it is not then maybe I should ask for a refund.

The cold didn't help there.

I agree.

That is the PSA.

As stated previously I still don't think that layer is PSA as it has not adhesive feel to it and is used to insulate the brown trace and to create the pads air gap.

I intend to do this repair as follows:

• Use a 12 port pcb plug and connector and a 12 conductor flat ribbon cable to bypass the existing ribbon. This 12 port plug will be soldered to the control board pcb in place of the existing connector for the existing ribbon. The other side of this 12 conductor ribbon will go into the keyboard membrane to be glued to the membrane traces with conductive glue.
• The broken silver traces will be drawn on the keyboard membrane with conductive adhesive/ink to repair them.
• The broken brown traces will be repaired using thin gauge Enameled Copper Magnet Wire which has insulation on it. They would be glued to the silver traces where needed using conductive glue.
• Any thinned out or broken pads will be retraced with conductive adhesive.
• Glue the broken piece of the electrical layer of the keyboard membrane.
• Then I will try to test the board and keyboard membrane for functionality (this would be challenging, I can try to reinstall the half done membrane and the control board back into the oven and then carefully push every button of the membrane to check for sound and operation if everything works as designed then do the final assembly of the membrane).
• Glue the other 2 layers of the membrane and then glue the membrane back into its frame.
• Screw the control board into the keyboard membrane and reinstall on the oven and check everything again.
• If all is good then finish by reinstalling the rest of the oven.

Of course I left out the tinting of the keyboard membrane from the above list. I have not looked into the tinting of the membrane yet. Hopefully that can also be done satisfactory too.

If anyone sees anything missing or not right from the list above please chime in.
Also if someone can suggest a good 12 port pcb plug and connector and 12 conductor flat ribbon for this job please give links and part numbers.
Links for conductive glue that you have used and are happy with would be appreciated.
Also links to other needed materials listed above.

One of the most challenging aspects of these types of repair is finding reasonably priced parts so any help in this department would be much appreciated.
Thanks.

 

As reference the wiring diagram of the membrane and the repair is shown in the following picture:
https://drive.google.com/file/d/1G75-Hk0Xo-5vK9zlIRDkukc9LiMrdqWs/view?usp=sharing

 

I checked Cir-Kit frame. Prices on the websites I checked were over $200
200$? What website is this expensive?

https://paceworldwide.com/cir-kit-basic-version-non-thermobond
Can you link to a site with lower prices?

What is your budget?

As was mentioned previously, there is no fixed budget but let's say $100.

Usually silver and brown are the same viewed from opposite sides.

This is definitely not the case here. I have explained in detailed in previous posts what each trace is and their purpose. In brief the silver trace is the main trace going from pad to pad and to the ribbon, the brown trace is jumpers for the silver trace. When 2 silver traces needed to be connected and this was not possible because another silver trace would be shorted then the brown trace which is electrically insulated from the silver trace was used to jump between the two intended silver traces. The brown trace was connected to the silver traces at the big dots.

What are you calling board?

By board I meant the keyboard membrane and the control board together. Of course if they only sold the keyboard membrane at a reasonable price that would also work.

Why did you ask for recommendations if you don't follow them?

I was at this store and they had this knife with this brand. Looked good so I bought it.
Recommendation is recommendation, not obligation. Thanks.

You are trying to repair/replace a 1000$ OEM part with 2$ budget?

I upped the budget a bit.

Useless, they only need the dimensions, matrix, and faceprints to reproduce.

This is good to know as I contacted an eBayer to check on the possibility of having this membrane reprinted. Thanks.
What is meant by matrix?
By faceprint you mean the oven's black interface for the user (the side that has the function of each button printed on it)?

https://paceworldwide.com/straight-run-track-pad-frame Far from 200$!

Please disregard the earlier quote/question in this regard, since you answered it here. This link is reasonable, thanks. I will have to check how to use these. Perhaps you can describe how they are used. Thanks.

You can also find it cheaper elsewhere than the manufacturer.

Great. I will search for it.

 

Blades wont fit on the wrong knife but you know best.

I got a refund for the knife.

 

I received a quote on having the membrane printed out but the quote is way too high.
Maybe if there were a few others wanting this or if I was enterprising enough to want to sell it to others on eBay it would work. Nevertheless I inquired further to see how much 10 of them would cost and would a second run cost lower or not. If I get a reply I will share it here.
Here is the quote.

Hi there,​

​

Thanks for all the information.​

​

size:424mm x 81mm​

tail length: 100mm​

22 keys, no emboss, no metal dome​

colors:4​

​

price for 1pc is $400​

shipping is $30​

 

That's a fair price given the original was probably more than double that.

Would you be able to design a pcb to fit the space with a window for the led display to show through.
JLCPCB are a Chinese board manufacturer that produce boards at very reasonable prices. for a 9" x 9" board they would charge $20.90 + $12 shipping and that would be for 5 boards. Plus some extra for the cutout, or you could do that yourself with a Dremel if you have one. the cost of small surface mount switches is $1.16 for 10 plus
https://www.pchub.com/uph-component-switch-push-button-48x48x08mm-short-leg-p95331
This may not be the correct switch to use, it is just an example of how small you can go, and slim you can go.
I think it would be suitable as it probably connects the two pins on the one side to the two pins on the other, but you would need to find a data sheet to be sure.

Then a plug and socket for disconnecting from your main board.
So for around $50 you could make a purpose built board with more dependable switches and connector.
Use your existing front cover to cover it and fix it on with silicone or something similar that can be easily removed.
Use KiCad for designing your PCB, and it can be a two sided board with a middle layer if needed in that price.
When designed submit the Gerber files to JLCPCB for a cost and if acceptable register and purchase.
If it all works sell the remainder as a repair kit for your oven mode on Ebay using the original spare part number in the title so people can find it.
The switch needs to be a momentary switch, that will connect just when pressed.
Do you realize that the existing membrane switches connect the front membrane to the back membrane and also connect the
the lighter membrane on the switch pad together. The switch is dual functional because the switch pad on the brown lighter side is constructed of fingers that when pressed connect both sides of the switch pad (which has an inlet and outlet) to the back pad so is in effect making two connections simultaneously.
I hope this gives you food for thought and a reliable cost effective solution.

 

If this is actually a viable approach, it could be a hell of a business opportunity. I think a lot of ovens hit the landfill for lack of a switch pad repair option.

 

If this is actually a viable approach, it could be a hell of a business opportunity. I think a lot of ovens hit the landfill for lack of a switch pad repair option.

My oven that I am using now was scrapped because AEG said they no longer had the power board for it.I researched it and the equivalent power board an OVC1000 was used in 14 other brands of ovens. So I got an £800 pound Stainless steel double oven for £60 and fully working with a new power board for £100.
I have just been sussing out tact switches and they go down to 4mm in size and only a few mm thick 1 or 2
If I was given an existing switch I am sure I could come up with a design to utilize the original switch face with a pcb behind to do the work.
You could use a thin acrylic sheet to take up the switch thickness on the board so that the button press depth was spot on and the button press depths are only 0.25 mm and 0.8 mm the thickness of the switch body.
Lots of design possibilities smd and through hole mounts, short legs on the smd and even no legs making them even smaller.

 

What about the thickness? It will stand out a lot. Tact switches are far less reliable than membrane keys, more so in extreme conditions faced in a kitchen.

Think about the heat required to solder them to a board, far hotter than any kitchen I ever worked in!!!

 

Tact switches are far less reliable than membrane keys, more so in extreme conditions faced in a kitchen.

Why? If it's because of moisture ingress, then a membrane over the tact switches should solve that.

 

That's why there is soldering time and humidity limits in the datasheets. Some manufacturers have used tact switches in the past and reliability was close to none.

It was just an idea, obviously you would avoid plastic switches, and check up the data sheets to see what they could theoretically withstand. as for thickness, you could get away with 2.4 mm, or thinner if you wanted to use a thinner PCB.

 

Heat, humidity and number of cycles are all inferior. Even sealed membranes eventually fail, hence this thread.

I would use the original membrane face off the existing switch panel to cover it so that would keep any moisture out, seal it down with auto grade silicone oil sealant, even get it in black to match the cover.

 

Regular silicone sealants and electronics don't mix well. Unless you are talking about silicone dieletric grease, even there most switches are not ok.

I would just seal around the perimeter of the board, it should keep out any fluids from cleaning and steam. Obviously not lathering and covering the switches in it.

 

Regular RTV silicone will destroy your circuit in short order. You need specially formulated silicone for electronics (read expensive) that won't erode your traces with it's acid.

I hope BJ is reading all of this and getting some ideas.

 

I just read all the newly posted replies. Thanks for the ideas.

I was still trying to find the right snap plug for pcb to solder to the control board as replacement for the original ribbon holder and a matching connector to snap into the plug. The new ribbon will then be soldered to this connector and the other side of the new ribbon will be glued to the membrane traces. The rest of the broken membrane traces will then have to be drawn on the membrane and the membrane glued back together.
Here is the plug, connector and ribbon and other materials I was contemplating to use from DigiKey:
Plug to be soldered to pcb
Connector to be soldered to new ribbon and snapped into the pcb plug above
New ribbon cable cut from this, then soldered on one side to connector above and on the other side glued to membrane traces
Conductive glue for connecting the new ribbon to the membrane traces and to recreate the broken traces
In addition the following items are likely necessary to do the repair as described above:
Conductive Pen
Clear Overcoat Pen

The problem with doing the repair as described above is that there are 2 traces on the membrane, one on top of the other with a very thin layer of insulation. These 2 traces have now been torn from each other due to the tearing that took place when attempts at separating the sandwiched layers of the electrical portion of the membrane was being attempted.

In addition it may NOT be possible, or very difficult, to access both traces. This is because trying to scrape the insulation to gain access to the traces hidden behind the very thin layer of insulation will almost certainly cause the traces to come off too. The aforementioned point is why I don't think this repair will be successful.

Let me explain the last point in the above paragraph a little further because it may not be readily understood. If there was only one broken trace, with pieces still on one side of the membrane then a conductive pen could be used to re-trace them and join the 2 broken traces together. But this is not the case here. The two traces go above and below each other, not only does this make the job of recreating the traces many folds more difficult but in addition there are pieces of trace on the torn portion under a layer of insulation and on the main portion also under insulation. This means portions of trace have to be connected from the torn portion to the main portion both of which are under insulation. This makes this repair extremely difficult and the chances of failure goes up exponentially. One has to also remember that this membrane buttons work based on a very small air gap created by the extremely thin insulating layer so if while doing this repair this gap is inadvertently increased it may cause the gap to be too wide and the buttons not work at all, or if the buttons still work with the wider air gap, they may need excessive push to make them work, making the repair a poor repair job.

So here is my dilemma with this repair: it is a challenging repair with low chance of full success, by the time the repair has been attempted the cost would have increased considerably and the control circuit would have been modified which then has to be put back into its previous state if a replacement membrane is what finally has to be bought.

I have not giving up fully on the above solution but it is now at the back burner while other solutions are contemplated.

As to the other ideas presented here I will read them more fully and respond with questions to clarify the concepts. Perhaps they are practical and can be attempted.