Midnight Puzzler

[JIMRPT@AOL.COM]

Hey here's a relatively easy one. :-)

Piano: Sojin Grand

Problem: Keys in the treble sticking occasionally and not always the same 
key(s).

Symptoms: Key bushings were free and clear, balance holes were loose almost 
pully, whippen and hammer flanges free to very minor friction, sticking 
problem only in treble area but there was a 'slight' occasional ticking noise 
on every key throughout the scale. The problem seemed to disappear with the 
action out of the piano, and before the cheek blocks and fallboard were 
reinstalled.

Question: What it was? :-)
Jim Bryant (FL)