mdodds
Posts: 1
Joined: Wed Feb 24, 2021 9:13 pm

Easy replacement keyboard for Pi 400

Wed Feb 24, 2021 10:21 pm

Thought this might come in handy in case you are a klutz like me :D
I spilled an entire cup of hot coffee right on top of my Pi 400. I immediately unplugged it and turned it over to drain, waited a while then tried it......no luck. Split it open and removed the keyboard and connected a usb keyboard and was relieved to discover that the Pi itself was fine. I rinsed the now disconnected keyboard in clear water and let it air dry for 24 hours. It mostly worked after that, but there were still a few non-functional keys.
What to do?
Well, I looked at some teardown articles for the official Raspberry PI keyboard and it looks just like the one on the 400. I ordered a black one and lo and behold it drops right in to the 400! The only difference I can see is the power LED is marked with a down arrow instead of the power symbol, and the F10 key isn't marked for power. Fn+F10 still works just fine as a power button, and the LED still functions as a power light.
So I now have a red bottom, black top fully functional (again) Franken-Pi 400!

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mahjongg
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Re: Easy replacement keyboard for Pi 400

Thu Feb 25, 2021 2:14 pm

To get a keyboard (or any other electronic device) working again after you spiled coffee on it.

If the device was off when you spilled coffee on it, then you were lucky, spilling coffee on a working machine is bad, as the coffee creates many short circuits, and if you are unlucky the shorts can cause latch-up damage (burn out transistors).

The best way to handle a keyboard you have spilled coffee on, is to turn the RPI 400 off *immediately*!

Then open the case up and rinse the coffee off under a tap with cold water, shake the water out multiple times, so as to remove all the coffee, for at least ten minutes.
let it dry toilet paper for at least a day.
Buy a litre of distilled water, and repeatedly rinse the keyboard again with distilled water, shaking the water out after each rinse.

Let it dry again on toilet paper.

lastly repeat again, but now with spiritus, or Rubbing alcohol (isopropanol). let is drench for 10 minutes, then shake the alcohol out and let it dry (let the alcohol evaporite) then let it dry on toilet paper again.

The reason for this procedure is to replace all the sticky coffee with clean water, coffee is conductive. Tap water however is also conductive, so we should remove it too, with distilled water, and isopropanol alcohol (which also contains small amounts of water, so you use at least 70% purer ethanoll, so no traces of (tap) water should remain,

after this you can carefully try the keyboard again. If there are still keys than don't work, that means the keyboard isn't completely free of water, or sugar particles, you can try the whole procedure again.

drgeoff
Posts: 12244
Joined: Wed Jan 25, 2012 6:39 pm

Re: Easy replacement keyboard for Pi 400

Thu Feb 25, 2021 4:34 pm

The RPi keyboard and the one on the RPi400 are membrane keyboards. If liquid gets between the two membranes it is exceedingly difficult to get it all out without separating them. Some designs have the backing plate attached by screws. Those can be unscrewed to reach the membranes and separate them. Unfortunately the RPi keyboards use heat stakes, not screws. Heat stakes are not readily remade by the average person.
Quis custodiet ipsos custodes?

ejolson
Posts: 8289
Joined: Tue Mar 18, 2014 11:47 am

Re: Easy replacement keyboard for Pi 400

Thu Feb 25, 2021 5:21 pm

mahjongg wrote:
Thu Feb 25, 2021 2:14 pm
To get a keyboard (or any other electronic device) working again after you spiled coffee on it.

If the device was off when you spilled coffee on it, then you were lucky, spilling coffee on a working machine is bad, as the coffee creates many short circuits, and if you are unlucky the shorts can cause latch-up damage (burn out transistors).

The best way to handle a keyboard you have spilled coffee on, is to turn the RPI 400 off *immediately*!

Then open the case up and rinse the coffee off under a tap with cold water, shake the water out multiple times, so as to remove all the coffee, for at least ten minutes.
let it dry toilet paper for at least a day.
Buy a litre of distilled water, and repeatedly rinse the keyboard again with distilled water, shaking the water out after each rinse.

Let it dry again on toilet paper.

lastly repeat again, but now with spiritus, or Rubbing alcohol (isopropanol). let is drench for 10 minutes, then shake the alcohol out and let it dry (let the alcohol evaporite) then let it draw on toilet paper again.

The reason for this procedure is to replace all the sticky coffee with clean water, coffee is conductive. Tap water however is also conductive, so we should remove it too, with distilled water, and isopropanol alcohol (which also contains small amounts of water, so you use at least 70% purer ethanoll, so no traces of (tap) water should remain,

after this you can carefully try the keyboard again. If there are still keys than don't work, that means the keyboard isn't completely free of water, or sugar particles, you can try the whole procedure again.
For the next wash I'd place the broken keyboard in the dishwasher no soap no heat cycle. After all the coffee is out it will likely fit on the black base of the new keyboard and you will have a spare.

Some people place uncooked rice in a sealed container to dry out the last bit moisture. Such tricks are not needed if you live in the desert.

petrsmrz
Posts: 1
Joined: Sat Jun 05, 2021 6:42 pm

Re: Easy replacement keyboard for Pi 400

Sat Jun 05, 2021 6:48 pm

I have keyboards for PI 400 (US) available as spare parts

0d0a
Posts: 13
Joined: Sun Feb 15, 2015 1:55 pm

Re: Easy replacement keyboard for Pi 400

Wed Sep 15, 2021 10:35 am

Can you send one to the Netherlands? Costs?

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Jeffry84
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Location: Trieste, Italy

Re: Easy replacement keyboard for Pi 400

Sat Oct 02, 2021 10:20 pm

It wouldn't be a bad idea to have replacements sold somewhere, so that it's not needed to get by with different pieces.

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HermannSW
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Re: Easy replacement keyboard for Pi 400

Sun Oct 03, 2021 6:52 pm

You can buy an official Raspberry keyboard for 17.99$ and use that as replacement keyboard for the Pi400:
https://www.raspberrypi.org/products/ra ... d-and-hub/

Opening a Pi400 is not difficult with just a screw driver, I did that very often when inserting an RTC into the Pi400:
Image
https://github.com/Hermann-SW/memrun
https://stamm-wilbrandt.de/2wheel_balancing_robot
https://stamm-wilbrandt.de/en#raspcatbot
https://github.com/Hermann-SW/Raspberry_v1_camera_global_external_shutter
https://stamm-wilbrandt.de/en/Raspberry_camera.html

andrum99
Posts: 1521
Joined: Fri Jul 20, 2012 2:41 pm

Re: Easy replacement keyboard for Pi 400

Sat Oct 09, 2021 12:27 am

I think it would be worth Raspberry Pi making replacement keyboards available as an FRU - just the keyboard itself, no PCB or bottom shell. This would reduce waste, particularly as the acrylic used to make the case is not recyclable. The latest keyboards are also better than the original version, so this would also give folk the option to upgrade at a lower cost.

It's slightly unfortunate the standalone keyboard product is not identical to the keyboard on the Pi 400 otherwise you could have the same FRU for both. (Yes, I'm aware there's several different regional variants). What if both keyboards were modified so that the one difference - power/ScrLk - could be switched in software on Raspberry Pi OS? It's fairly common for PC keyboards to have some sort of power key - obviously when connected to a Pi the OS would shutdown but not power off the board. That way each country variant of the keyboard would be identical for both Pi 400 and standalone keyboard, allowing them to share a replacement keyboard FRU. And more adventurous users could apply the replacement as a CRU. You would need to modify the product name slightly to distinguish it from the non-identical version - not sure the best of doing that - maybe something like 'Raspberry Pi Keyboard v2' and have them all be the new improved version of the keyboard? And 'Pi 400 v2'.

I think there's going to be more demand for replacement parts as keyboards break, as all mechanic devices eventually do.

andrum99
Posts: 1521
Joined: Fri Jul 20, 2012 2:41 pm

Re: Easy replacement keyboard for Pi 400

Sat Oct 09, 2021 12:31 am

I had to replace the keyboard on my old laptop after spilling apple juice on it, even after running it under the tap. It was a Toshiba which claimed to be resistant to up to 100ml of water spillage.

The rice thing is a waste of time - just air drying it in the open air is just as effective.

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