[Amps] Alpha 77D amp question

[Louis Parascondola]

Anybody have a a 77d dx or sx?  Got one here I am repairing.  Looks like I may have taken care of the electronic problem and now I have found what seems to be a mechanical problem..  The turns counter on the front panel has a metal circular pad with a male cut out for the plastic interface to the vacuum cap.  Then comes the double female plastic interface between the turns counter and the vacuum variable.  There is quite a large space, at least an 1/8" between the interface and the counter.  As a result there is no connection to the vacuum cap and it won't turn.  I am not sure if something is missing or what but the only way I can get it to work is to press hard against the front panel so the it pushes the counter closer so it fits in the groove.  I don't see an adjustment where somehow the space can be taken up.  Maybe the plastic interface is worn?  Maybe something is missing?  I see no way to pick up the difference and can't see how it ever worked.  Any help?  Lou