Thanks Glen, Jay and Bob, I think that I now understand what's going on. The system that the keyboard comes from is an E series machine but all of the cards have been removed - it is quite possible that it at some time had additional booster microcode boards so that would expain the extra front panel cable. What sort of microcode board would require direct access to the keyboard? Bob - thanks for the kind offer of the 2113 chassis. I currently have a couple of full size 2113's in almost working condition (thanks for your continuing help on that one) my hope was that I could get a smaller system working as well - hence the need for the short keyboard. Glen - the document that you linked shows the problem quite well. What I need is the PCA 5060-8343 what I have is PCA 5061-1343. The metal work changes to convert a long front panel to a short one look to be fairly minimal and are probably within my capability (injury estimate: 2 bruised knuckles, a gash and some sort of deep graze) I note from the circuit diagrams that the keyboards are basically the same with the larger PCA having some addtional bi-directional buffering to drive the additional keyboard outputs. I thought that I might be able to saw down the keyboard PCA and discard the extra buffering bits but they seem fairly well integrated into the rest of the PCA. Does anyone have a spare 5060-8343 that they might be convinced to part with? or failing that a whole front panel assembly for a 2105? Thanks to all Peter Brown