Amiga 2000 keyboard repair

cyberfox_it · 24 January 2016, 09:42

Hello,

I've a problem with my amiga 2000 keyboard, inside there's a mitsumi board.

The problem is the left amiga key, that as you can see in the photo doesn't look as the other keys.

Anyone as had a problem like mine ? How can I repair it ?

Thank you very much

Turran · 24 January 2016, 10:52

Seems to have worn off the graphite. You can repair it with something like this

http://www.ebay.com/itm/REMOTE-CONTR...3D231806205918

Its quite easy to overdo it though and put too much on. Practice on something else first so it does not flow out too much or build too high. Takes a while for it to harden though so you have time to clean it up if you make a mistake.

Clean pads, apply a little liquid graphite on it. Let it dry, done!

cyberfox_it · 24 January 2016, 14:56

Quote:

Originally Posted by Turran

Seems to have worn off the graphite. You can repair it with something like this

http://www.ebay.com/itm/REMOTE-CONTR...3D231806205918

Its quite easy to overdo it though and put too much on. Practice on something else first so it does not flow out too much or build too high. Takes a while for it to harden though so you have time to clean it up if you make a mistake.

Clean pads, apply a little liquid graphite on it. Let it dry, done!

Thank you very much for your advice, have you already tried ?

idrougge · 24 January 2016, 16:28

You can try a short-term fix by overwriting the worn pads with a pencil first.

Turran · 25 January 2016, 17:01

Quote:

Originally Posted by cyberfox_it

Thank you very much for your advice, have you already tried ?

Yeah, I've used it on A4000 keyboards. Works a treat =)

jbenam · 25 January 2016, 17:24

Quote:

Originally Posted by Turran

Yeah, I've used it on A4000 keyboards. Works a treat =)

Thanks for the link! I think my A4000's KB will need a bit of it as well, one of the two SHIFT keys isn't working anymore

amigasith · 25 January 2016, 21:18

I tried to repair my German A4000 keyboard with graphite the other day. I used this stuff here, but it didn't work for me at all.

In my case, the membrane wasn't the culprit, but a few of the key stamps had extremely high resistance values when measured with a multimeter. Can't remember off the top of my head, but somewhere in the few kOhm range. The working ones were something like 300-400 Ohms.

I tried many variations, and it didn't matter how much or how little graphite I applied to the key stamps, the conductivity didn't improve. Therefore, I really wonder why this method supposedly worked for so many other people. I ended up buying a few replacement key stamps and now my keyboard is working great again.

Maybe graphite works better for the membrane, but at least for the key stamps, it is not a perfect solution in my experience.

zipper · 25 January 2016, 22:43

Depends of the graphite source, how pure it is.

Jope · 26 January 2016, 09:11

Use the paper trick on the rubber conductors under the key stems instead graphite.

idrougge · 26 January 2016, 16:00

Paper trick?

Jope · 26 January 2016, 18:56

Take some ordinary copier paper and wipe any shiny rubber contacts with the paper until they are dull again.

Clean any dust with q-tips and iso alcohol and reassemble.

Mess free, restores them to as new condition.

Doesn't help it when some friend has taken sandpaper to the PCB as in the picture above, but there you can try the liquid graphite trick.

cyberfox_it · 06 February 2016, 21:10

I've not used any sandpaper, the contacts on the pcb was white instead of black, I removed the most with my finger, but there's some remains as you see in the picture.

I'll try to clean it with alchool, and to apply the graphite...

Quote:

Originally Posted by Jope

Take some ordinary copier paper and wipe any shiny rubber contacts with the paper until they are dull again.

Clean any dust with q-tips and iso alcohol and reassemble.

Mess free, restores them to as new condition.

Doesn't help it when some friend has taken sandpaper to the PCB as in the picture above, but there you can try the liquid graphite trick.

24 January 2016, 09:42	#1
cyberfox_it Registered User Join Date: Jun 2009 Location: Verona/Italy Age: 51 Posts: 38	Amiga 2000 keyboard repair Hello, I've a problem with my amiga 2000 keyboard, inside there's a mitsumi board. The problem is the left amiga key, that as you can see in the photo doesn't look as the other keys. Anyone as had a problem like mine ? How can I repair it ? Thank you very much Attached Thumbnails

24 January 2016, 10:52	#2
Turran Moderator Join Date: May 2012 Location: Stockholm / Sweden Age: 49 Posts: 1,572	Seems to have worn off the graphite. You can repair it with something like this http://www.ebay.com/itm/REMOTE-CONTR...3D231806205918 Its quite easy to overdo it though and put too much on. Practice on something else first so it does not flow out too much or build too high. Takes a while for it to harden though so you have time to clean it up if you make a mistake. Clean pads, apply a little liquid graphite on it. Let it dry, done! Last edited by Turran; 24 January 2016 at 11:07.

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24 January 2016, 16:28	#4
idrougge Registered User Join Date: Sep 2007 Location: Stockholm Posts: 4,332	You can try a short-term fix by overwriting the worn pads with a pencil first.

25 January 2016, 21:18	#7
amigasith Registered User Join Date: Jan 2013 Location: Wild South / Germany Age: 48 Posts: 271	I tried to repair my German A4000 keyboard with graphite the other day. I used this stuff here, but it didn't work for me at all. In my case, the membrane wasn't the culprit, but a few of the key stamps had extremely high resistance values when measured with a multimeter. Can't remember off the top of my head, but somewhere in the few kOhm range. The working ones were something like 300-400 Ohms. I tried many variations, and it didn't matter how much or how little graphite I applied to the key stamps, the conductivity didn't improve. Therefore, I really wonder why this method supposedly worked for so many other people. I ended up buying a few replacement key stamps and now my keyboard is working great again. Maybe graphite works better for the membrane, but at least for the key stamps, it is not a perfect solution in my experience.

25 January 2016, 22:43	#8
zipper Registered User Join Date: Mar 2004 Location: finland Posts: 1,838	Depends of the graphite source, how pure it is.

26 January 2016, 09:11	#9
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Use the paper trick on the rubber conductors under the key stems instead graphite.

26 January 2016, 16:00	#10
idrougge Registered User Join Date: Sep 2007 Location: Stockholm Posts: 4,332	Paper trick?

26 January 2016, 18:56	#11
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Take some ordinary copier paper and wipe any shiny rubber contacts with the paper until they are dull again. Clean any dust with q-tips and iso alcohol and reassemble. Mess free, restores them to as new condition. Doesn't help it when some friend has taken sandpaper to the PCB as in the picture above, but there you can try the liquid graphite trick.

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