Apple Keyboard M0116 recap

IBM Heretic

New Tinkerer
Nov 27, 2024
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Hello all,

I apologize if this has been covered, I did search but was unable to find any information here, other forums, or YouTube videos (some even claiming "full restoration").

I am beginning the process of a restoration on the Apple Keyboard m0116, and I've identified two capacitors to be replaced. My issue is that the markings on them don't add up. They're relatively small, aluminum electrolytic, with a 3mm lead spacing, approximately 1cm tall and a half centimeter wide. These tiny caps are labeled as having a 1mF capacitance and rated for 50v.

I don't believe that's possible in a package of this size and I can't find anything with these specs in this or close package on Mouser or Digikey.

Has anyone performed a recap of this keyboard, or perhaps point me in the right direction? It seems like they should be 1uF and are simply mislabeled, and they both clearly show 1mF. I ran a capacitance test in-circuit and they both report approximately 3uF.

Thank you so much
 

wottle

Active Tinkerer
Oct 30, 2021
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Pretty sure that is just how some manufacturers printed microfarad when they couldn't produce the µ character on their caps. It certainly is not megaFarads
 
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JDW

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Sep 2, 2021
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I deyellowed that Apple M0116 keyboard back in 2019 and also swapped the two capacitors out for tantalums at that time. My writeup is found here:

I'm upset with myself for not having written what the C1 & C3 values were.

Capacitors.jpg

But after much Googling I found them here:

Both 1uF, as in MICRO FARAD. If memory serves, I probably used 35V dipped tantalums as replacements, because that is what I had on hand at the time.

Engineers of old really irk me. They often write mF but mean µF. But you can figure it out based on Physical Size. A 50v 1 millifarad cap would probably be 18mm wide and 35mm tall — pretty massive, and clearly not able to find on a keyboard.

Anyway, in my search for the cap values, I came across a guy who recreated the keyboard. Pretty interesting...

 

IBM Heretic

New Tinkerer
Nov 27, 2024
2
2
3
I deyellowed that Apple M0116 keyboard back in 2019 and also swapped the two capacitors out for tantalums at that time. My writeup is found here:

I'm upset with myself for not having written what the C1 & C3 values were.

View attachment 18760

But after much Googling I found them here:

Both 1uF, as in MICRO FARAD. If memory serves, I probably used 35V dipped tantalums as replacements, because that is what I had on hand at the time.

Engineers of old really irk me. They often write mF but mean µF. But you can figure it out based on Physical Size. A 50v 1 millifarad cap would probably be 18mm wide and 35mm tall — pretty massive, and clearly not able to find on a keyboard.

Anyway, in my search for the cap values, I came across a guy who recreated the keyboard. Pretty interesting...


Thank you to everyone. I'm going to replace these with tantalums.

Cheers