Keyboard keys suddenly stopped working

[KasefTamjid]

I have this keyboard,a marvo km400. I was playing games today and suddenly noticed the M key, N key and th Fn key is not working. So thinking it was dust, I opened the keyboard and basically did nothing more than taking photos and blowing some dust of (ps. There was almost no dust on the membrane of the keyboard). So I put it back together and tried to turn it on but this time a lot of keys are not working?!! I resetted and reinstalled the HID keyboard drivers but to no avail. This keyboard is very dear to me. So BUYING ANOTHER IS NOT AN OPTION. I have attached photos of the circuit and membrane. I have basic soldering and electrical knowledge (hobbyist) so keep that in mind.


TL;DR.. Keys suddenly stopped working, more keys not working after disassembly-reassembly, How do I fix it?

Please dont tell me to buy a new one, it isnt a option right now and as I stated before, this thing is very near to me for specefic reason.

UPDATE:- I opened the keyboard again and thoroughly checked for problems, it seems like the graphite connectors were not connected properly hence more keys were not working. But I did discover that Keys (chain) connected to C16 were not working (M,N,Backspace,right arrow etc.) so I tried cleaning and better and tighter fit, I also tried to sketch it using a pencil for better connection. Still, these specefic keys are not working. Pics :-...

https://drive.google.com/folderview?id=1-bMCayz_kNs-ReTMJEOFYjMQRvb-ADls

 

[learninmypc]

Is this it, or similiar https://sg.carousell.com/p/marvo-km400-scorpion-gaming-keyboard-used-182214805/ if so, I know this sounds bizarre but weather proof the usb if it has one & put it in the shower for several minutes, let it COMPLETELY dry & see if it works. I have this kb https://www.extremetech.com/computing/58888-saitek-eclipse-ii-keyboard-review & had similiar problems, washed it & as you can see by my typing, it works. MAY NOT work for ALL KB's .

 

[KasefTamjid]

Is this it, or similiar https://sg.carousell.com/p/marvo-km400-scorpion-gaming-keyboard-used-182214805/ if so, I know this sounds bizarre but weather proof the usb if it has one & put it in the shower for several minutes, let it COMPLETELY dry & see if it works. I have this kb https://www.extremetech.com/computing/58888-saitek-eclipse-ii-keyboard-review & had similiar problems, washed it & as you can see by my typing, it works. MAY NOT work for ALL KB's .

... Actually this doesnt seem like a bad idea. But im confused how that might help. Im pretty sure the membrane contacts below the keys are okay. And if I am to try this ( desperate measures...) do I need to water proof the whole circuit, or just the usb port which I guess is to protect from rust?

 

[KasefTamjid]

And yes, the link you provided does seem very much like my one

 

[learninmypc]

... Actually this doesnt seem like a bad idea. But im confused how that might help. Im pretty sure the membrane contacts below the keys are okay. And if I am to try this ( desperate measures...) do I need to water proof the whole circuit, or just the usb port which I guess is to protect from rust?

In my case, I simply TIGHTLY wrapped duct tape around the USB plug to about an inch above it, set it on my shower floor & turned the shower on allowing the water to penetrate ALL areas. That lasted a few minutes, turned water off & stood there a few minutes for it to drip dry. Let it sit in my room for a few days hoping it would dry, plugged it into my desktop & I am using it right now. I had spilled coffee & probably crumbs of some sort on it. My kb as you saw in my link has 3 different back lit colors for my keys, those still work as does the kb. IF you don't feel comfortable doing same, don't. I won't be held responsible. Google to see if you can do such, good luck. Alternately you can use a dishwasher but DO NOT DRY it in there or use soap.