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Improving a PowerBook Duo keyboard

beachycove

Well-known member
I came across this while wandering the interwebs the other day, on the archived Japanese CCSCC (Color Classic hot-rodding) website. One of us ought to give it a try over a couple of cold winter nights, as a stock Duo keyboard is such crap.

http://web.archive.org/web/20030604083159/http://kanchan.hn.org/duokeyb.html

And, for convenience, here it is, copied and pasted.



Duo keytouch improvement



Duo keybord feels very wheak. And easily be less-reaction.
I show easy repairing of Duo keybord. You need 0.3mm stainless steel (or durable alminium) plate and Circuit Repairer of rear windows of car.

1. Pick out the keybord from Duo.
2. Remove all keytops.
3. Remove rubber sheet.
4. Apply Circuit Repairer glue on the terminal of the riverse side of the rubber sheet. 
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5. Put all keytop again after drying glue up well. 
6. Cut stainless plate at the same pattern of the riverse side of keybord. 
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7. Pile up this plate to original steel plate and fasten them together.

 

douglasgb

Member
Mine is much better. I did not use 'circuit repairer glue' which I assume is like CaiKot 44. I did clean them with a Q-tip and isopropyl alcohol. The real problem I found was that the two sheets of clear plastic that have the conductive areas were simply not laying flat, and making the keys far too springy.

I don't know if there are different version of the keyboard, but mine has a lower sheet with small holes for each key post, with crescents of conductive material for each key. The upper sheet has larger holes that expose the crescents from the lower sheet and also has the other part of the crescent for each key. When the key is pressed, it bridges the two areas. 

To make the two sheets lay flat, I sprayed their back (blank) sides with a very, very light coat of 3M spray adhesive (Super 77) and per the instructions let it set for a few minutes. Spraying the adhesive on the back is critical so it does not interfere with the conductive material.

I then held the right and left edges of the lower sheet and let the center droop down just above the base of the keyboard. This allowed me to position it in the proper place as I lowered it until it made contact. At this point it is still possible to reposition and make sure it is not rotated. I lowered one side completely and then used that hand to press it down, working from the center out to the edge. Then I pressed down from the center to the other edge as I lowered it into place.

I repeated this careful alignment / installation process for the second (upper) sheet. When I was done they were flat, and I could see the root of the problem: they are a tiny bit too wide! I don't know if that's because the base has shrunk a little or what. I did not feel the need to trim the edges of the plastic but that is an option.

After this operation the keys are much more responsive and have a greatly improved feel. The bottom corners of the keyboard do still dip when the ctrl/arrow keys are pushed, but that's a different problem (need to stiffen the entire assembly). With the improvement gained by the above, I decided I didn't need to do anything about that.

 

sutekh

Well-known member
Very interesting! I love my 280c, but its keyboard is terrible. Anxious to give this a try!

 
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