I have encountered this problem a few times too many in the last month.
Item> A 40 year old Acrosonic that works great and sounds ok EXCEPT for one or two notes that don't always function correctly. Every so often the Note ( near C40) will just try to freeze and become rather hard to get through escapement. There is a pronounced let-off and aftertouch. The rest of the time it is fine. Now one thing, when you engage the left pedal, that particular key and others that are doing the same thing during escapement, ,dip when the left pedal is pushed. Am I looking at some kind of spoon problem??? Tom.....

Was it not maybe a previous tuners adjustment made to overcome tight pinning who had no protek with him?

If there is no pocket on the buckskin of the hammer butt nor an aberration on the tip of the jack, the problem may be the result of tight bridle strap. Bend the bridle strap wire forward a bit to see if it alleviates the problem.

Eric

The acrosonics from the 70's(and perhaps even the 80's) DID have bridle wire adjustment problems. However, this may also apply to this one though the age is given at around 40 years.

Mark Mandell www.pianosource.com

It is getting pretty old for a spinet. Most spinets including the acrosonic are very difficult to work on. The actions are too compact and take too long to remove and replace in the piano, which frequently must be done several times when adjusting. Think about getting a new piano. Be careful of the Baldwin warranties and get everything in writing from the dealer. Make sure the local dealer guarantees it [Baldwin] personally. Try to buy a console or bigger.

EUREKA!!!! I have found it!! (With a little help from my friends).. It WAS the bridal tape & wire. The wire did NOT have a complete loop in it on that year Acrosonics. It only had a bend, so the tape sometimes slipped down (Just a little bit) and changed the touch, BIG TIME. Thanx for all the clues you gyuys sent me.