I suddenly find myself in the position of needing to evaluate a couple of concertinas to see what work they need. It made me wonder if anyone has produced (or could be tricked into producing) a checklist of issues as a guide to assessing the condition of a concertina. Some things of course jump out - notes that don't play, pads that don't seal, etc. Others you pick up in playing, for example on one instrument the buttons protrude too far, wobble badly in the out position, dip too far and require far too much pressure when pressed. Some need investigating to find, like end screws with only a turn or two of useable thread or action cover sides held in place only by the screws, as the glue joints have come apart.
Hmmm, if I go on like this for much longer, I won't need a checklist. But if anyone has one....
Terry