Leopold FC900R Water Damage

[hxu04]

Hello, my mom accidentally spilled water in a few weeks ago, but I couldn’t act until now because I was busy and exhausted from work. I only turned off my computer and cleaned the water, I didn’t realize I should unplug it and place it downwards. It was fine the first few days, but then some keys aren’t responsive anymore.
I would like to know if my keyboard is hotswappable and how do I troubleshoot it? How do I know if I only need replace the switches or the PCB is damaged? Thanks.

The keys without key caps are non functional keys.

[Vescovo Alessio]

First of all I suggest you try to open the switch: extract the shaft and spring and check if water has entered inside. Check if the contact has made a slight oxide. You should also open the case and dry the back well. Many electronic parts are sealed and so tolerate being wet, but then need to dry...

[Prince Valiant]

https://mechanicalkeyboards.com/shop/index.php?l=product_detail&p=5658
"Hotswap Sockets   No"

Seems unlikely that the board is damaged if the rest of the switches are working.

[HungerMechanic]

Leopold keyboards are *not* hotswappable, so I do not recommend trying to remove any switches. Nor do I recommend trying to open switches.

You can remove the keycaps and try to ventilate your keyboard as you might do with a mobile phone that has been exposed to water.

However, if those switches don't come back to life, I wonder if it is the switches or the PCB that are damaged. If it is the PCB damaged, you are in big trouble, that keyboard is basically dead.

However, if the PCB is still working, then hypothetically new switches could be soldered onto the PCB. It is a big project to desolder the switches and put in new ones, but at least you would be able to keep the keyboard that way. If the PCB is dead, the only thing salvageable from your Leopold are the keycaps and power cable.

[hxu04]

Leopold keyboards are *not* hotswappable, so I do not recommend trying to remove any switches. Nor do I recommend trying to open switches.

You can remove the keycaps and try to ventilate your keyboard as you might do with a mobile phone that has been exposed to water.

However, if those switches don't come back to life, I wonder if it is the switches or the PCB that are damaged. If it is the PCB damaged, you are in big trouble, that keyboard is basically dead.

However, if the PCB is still working, then hypothetically new switches could be soldered onto the PCB. It is a big project to desolder the switches and put in new ones, but at least you would be able to keep the keyboard that way. If the PCB is dead, the only thing salvageable from your Leopold are the keycaps and power cable.

Then how would I know if the PCB is damaged or not? It seems really hard to check the state of the keyboard, because the design of this keyboard. From what I searched around the forum, it's quite hard even try to open the case if you are inexperienced.

[HungerMechanic]

I regret that I cannot answer your question about testing the PCB on a Leopold, since it may be difficult to disassemble.

If you like, I can forward your question on to a different forum.

[Prince Valiant]

Are the other keys still functioning?

[hxu04]

I regret that I cannot answer your question about testing the PCB on a Leopold, since it may be difficult to disassemble.

If you like, I can forward your question on to a different forum.

Yeah, that will be great. I work in a avionics company, so I could get the instructions to troubleshoot, I might ask the technician that I know to help me.

[hxu04]

Are the other keys still functioning?

Yes, only the keys without key caps are responsive

[Prince Valiant]

Are the other keys still functioning?

Yes, only the keys without key caps are responsive

The PCB is presumably fine if that's the case. You can try opening the switches as suggested, take care, and if that doesn't work you can desolder the non-functioning switches and solder on working ones.

[HungerMechanic]

I have posted the problem with the FC900R in another forum. Here is the first reply:

I repaired a WASD Code not too long ago with the same problem.
I had to desolder all the switches to have access to the PCB, and found that some traces were broken because water came in a few vias and corroded the copper.
I had to reroute the traces with wires to make it work again.

The switches were all fine, but it may me different in your case.
If you want to be sure then a multimeter and an access to the bottom of the PCB will tell you.
If the switches are really not working, then it is a matter of desoldering the dead ones and solder new ones.
If the switches are making contact then it may be a PCB problem…

[HungerMechanic]

Here is another reply:

First thing to do is get a multimeter, switch it to beep-on-short testing mode, have someone ready to press a bad key, touch the two probes of the meter to the solder points of the bad switch in-situ, and have your assistant press and hold the key. It should beep if the keyswitch is working (and I expect this to be the case because water doesn’t usually get into the keyswitch enough to affect the crossbar, it usually soaks the base under the plastic bottom half).

Do this test for each keyswitch. This test saves you the trouble of desoldering perfectly good switches. If you find that any switches are bad, of course, you’ll replace them. If they all work, then it would be a matter of PCB vias being corroded and having to route around the broken vias using thin wires.

[hxu04]

Are the other keys still functioning?

Yes, only the keys without key caps are responsive

The PCB is presumably fine if that's the case. You can try opening the switches as suggested, take care, and if that doesn't work you can desolder the non-functioning switches and solder on working ones.

So if this is the case, all I need to is replace the non-functioning switches? Are those the right switches I should buy?

https://keychron.ca/collections/keychron-mechanical-keyboard-switches/products/cherry-switch-set?variant=40101542035539

[hxu04]

Here is another reply:

First thing to do is get a multimeter, switch it to beep-on-short testing mode, have someone ready to press a bad key, touch the two probes of the meter to the solder points of the bad switch in-situ, and have your assistant press and hold the key. It should beep if the keyswitch is working (and I expect this to be the case because water doesn’t usually get into the keyswitch enough to affect the crossbar, it usually soaks the base under the plastic bottom half).

Do this test for each keyswitch. This test saves you the trouble of desoldering perfectly good switches. If you find that any switches are bad, of course, you’ll replace them. If they all work, then it would be a matter of PCB vias being corroded and having to route around the broken vias using thin wires.

Thank you! Sorry for the late reply, I just moved, so I didn't have internet connection for the desktop for a while. I will ask the technician I know to help me with that. And in case of failing  switches, are these switches the right type I should buy?
https://keychron.ca/collections/keychron-mechanical-keyboard-switches/products/cherry-switch-set?variant=40101542035539

[Prince Valiant]

That looks to be correct.

[HungerMechanic]

Thank you! Sorry for the late reply, I just moved, so I didn't have internet connection for the desktop for a while. I will ask the technician I know to help me with that. And in case of failing  switches, are these switches the right type I should buy?
https://keychron.ca/collections/keychron-mechanical-keyboard-switches/products/cherry-switch-set?variant=40101542035539

Yes, if you end up replacing switches that are non-functional onto a working PCB, then those Cherry MX Blue switches should work fine.

I think you are ordering plate-mounted switches there, which is probably what you want. Let me double-check on this (it's not a big deal).

[HungerMechanic]

Ideally, you will order switches with 3-pins on the underside, as you see at Keychron.

If you end up with 5-pin switches, that's okay. You can always clip the extra pins off if you need to. Don't worry about it.

The ones from Keychron are probably legitimate Cherry switches.

Be careful! Desoldering and then resoldering is a major operation.

[hxu04]

Ideally, you will order switches with 3-pins on the underside, as you see at Keychron.

If you end up with 5-pin switches, that's okay. You can always clip the extra pins off if you need to. Don't worry about it.

The ones from Keychron are probably legitimate Cherry switches.

Be careful! Desoldering and then resoldering is a major operation.

Thanks for the confirmation. Yes, I will be careful with the soldering.