First, there is no fluid-filled electrolytic capacitor on earth that has eternal life. Next, I have experienced bad caps on my IIgs ADB keyboard attached to my SE/30. My SE/30 would hang suddenly for no apparent reason, and then I traced the problem to the electrolytic cap. After changing the cap, I never had that problem again. So yes, they do go bad, just like any other cap of that sort. Replace with tantalum and then you never need to worry about it again.
The reason I am asking is because I've just finished a new video (not yet public) about the recapping of the 128K-512K motherboard and keyboard. The procedure is similar for the Mac Plus, so I want to add those caps too, in the text description below my video on YouTube. I know the motherboard caps, and I know the Japanese variant of the extended keyboard's caps. I just don't know about the axial caps on the other extended keyboard variants.
So any kind help you can offer in that regard would be appreciated. Specifically...
1. Capacitance Spec (printed on capacitor)
2. Voltage Spec (printed on capacitor)
3. Type: Axial or Radial
4. Quantity (please check under the black metal frame so you don't miss any electrolytic caps)
5. How much clearance, or how fat (diameter) can the replacement cap be, to fit into the stock location? This is important because it seems some axial fit underneath that metal frame, so I want to know the maximum diameter it can be to fit there.
THANK YOU!