Priest of the Order of the Butterfly
Posts: 876 from 2012/11/10
From: Manchester, UK/GB
The PowerBook keyboard has a multi-layered contact membrane that is folded back onto itself, as in its a double width membrane, but with contacts that extend past/through/onto the folded section and under/over the 2nd layer, if I remember correctly
It is an almost impossible task to repair the membrane contacts as they are silver coated lines that are laid onto the clear keyboard membranes like painted lines. The membranes are extremely thin, and look like 1 layer, but if you are extremely careful you can peel them apart, but the danger is of the 'silvering' being damaged, possibly irrepairably as you separate the layers. Sometimes warming the membranes can allow the adhesive holding the layers together to come apart more easily, and without being too destructive to the surface layers. Additionally, over time, and liquid spills onto/between the metal layers the silver paint gets contaminated, burnt-out, deteriorates or flakes off, stopping the keypress making its contact.
You can use windscreen re-silvering paint (usually for heated rear windscreens repair) to 'paint' in the gaps/lines/on and between the keypress contacts and get some keyboards working again, which I have done a few times successfully. However, it's a time consuming and unreliable task, but if you've no other means of repair, or want to try that first then give it a go.
MacMini 1.5GHz,10,2,64MB VRAM,1GB,Airport, Bluetooth,A1016 Keyboard,T-RB22 Mouse,DVD-RW-DL+CD-RW,Iomega MiniMax,Belkin 6 port 3 x Firewire/3 x, USB2, MorphOS 3.12, Mac OSX 10.4/10.5, A1138+A1139 PwrBk MOS v3.12,Model 5,8/5,9, & PowerMac G5 2.3GHz(DP)