Looking for advice fixing a defective Apple AEK M0115

[Rami]

My Apple M0115 got messed up over night after using it for a year at my main PC. I can't see anything wrong with the PCB here, all the joints look good and all the traces are intact. After turning on the PC today for some work the entire bottom two rows appeared to have stopped working except for the B and full-stop, comma and slash. If I push a bunch of random buttons on these bottom rows they will register key presses elsewhere in the home row. In the case that the controller is fried, is there anywhere I could source a replacement? I don't think this one is reparable unfortunately but I would appreciate any advice as I would love to keep using this keyboard.

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[Willy4876]

I'd look for corrosion between traces or for leaked electrolyte from capacitors. Either of these can connect parts of the circuit that shouldn't be connected and could cause this kind of failure.

The fact that you have some functionality sounds to me like it can probably be salvaged.

If you can't find and fix the problem this guy has some for sale. I haven't dealt with him, and I know a bunch of people on here don't like him, but it's worth a shot.

https://keebmeup.com/index.php?id_produ ... er=product

Good luck with troubleshooting.

[Rami]

I'd look for corrosion between traces or for leaked electrolyte from capacitors. Either of these can connect parts of the circuit that shouldn't be connected and could cause this kind of failure.

The fact that you have some functionality sounds to me like it can probably be salvaged.

If you can't find and fix the problem this guy has some for sale. I haven't dealt with him, and I know a bunch of people on here don't like him, but it's worth a shot.

https://keebmeup.com/index.php?id_produ ... er=product

Good luck with troubleshooting.

Thank you for the advice! I believe I've tracked down the problem, it looks like a capacitor or some type of diode between the mounting plate and PCB blew up in my keyboard recently as I can see these black marks here going outward from these two leads right where the defective row of keys begins. They appear to be on the other side of the board as I can't seem to wipe them off. I will likely need to desolder all the switches and take off the mounting plate to confirm and to do the repair..

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[Willy4876]

I'd look for corrosion between traces or for leaked electrolyte from capacitors. Either of these can connect parts of the circuit that shouldn't be connected and could cause this kind of failure.

The fact that you have some functionality sounds to me like it can probably be salvaged.

If you can't find and fix the problem this guy has some for sale. I haven't dealt with him, and I know a bunch of people on here don't like him, but it's worth a shot.

https://keebmeup.com/index.php?id_produ ... er=product

Good luck with troubleshooting.

Thank you for the advice! I believe I've tracked down the problem, it looks like a capacitor or some type of diode between the mounting plate and PCB blew up in my keyboard recently as I can see these black marks here going outward from these two leads right where the defective row of keys begins. They appear to be on the other side of the board as I can't seem to wipe them off. I will likely need to desolder all the switches and take off the mounting plate to confirm and to do the repair..
20211114_010505.jpg

I don't believe that the AEK has any diodes in the matrix, so that component is probably just a jumper wire. Wires don't normally break without a decent amount of force. Its solder joints look good, so it's probably fine. The black spot on the trace in your photo looks like it could be corrosion or maybe some other damage (I circled the one I'm referring to in red in the attached photo). If the trace is broken at that spot then you can fix it by soldering a wire across the damaged section. The green line in the photo is where I think it would be would easiest to run a jumper wire, but I will leave that up to your judgement.

If you have a multimeter you can measure the resistance between the two sides of the trace to check for damage. The resistance between any solder joint on one side of the black spot to a solder joint on the other side should be very low.

Spoiler:

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[Rami]

I got the keyboard fixed and the issue was caused by a lifted pad on this solder joint. Using a multimeter I was able to tell that this circuit was not fully connected and managed to repair it with a wire. This is not the first time I had to repair a lifted pad on an old keyboard. Pardon my horrendous soldering work.

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[Muirium]

If it works, it works. Congrats on figuring it out.