[CAUT] Young Chang action troubles (?)

[Cramer, Mark]

I worked on a 15-year-old Young-Chang grand for a new client today, and the action has REAL problems.

Some of the issues I've either seen before, or read discussions about here on our list, i.e.: "bad knuckles & seized action centers."

However, one thing has me perplexed, and as I don't see very many of these instruments, would appreciate the experience of you those of you who have.

The big question is why "ALL" hammers were blocking at the strings? (no let-off)

I gave all the buttons a quick 1/2 turn down and went ahead with tuning and assessment. What set me off though, is this is the same intial intoduction I had to one other Young Chang grand, four years ago, and I've yet to solve it!

With that instrument, I followed the initial visit several weeks later with a re-tuning and a one-day regulation. That particular piano appeared much like brand new, and I was quite pleased (read "smug") with the results.

When I returned six months later however, let-off had dropped below the point of drop contact! (?) 

I spent a 1/2 hour poking around for clues... loose let-off rail, change in humidity, loose action brackets, severed key-bed, loose plate fit, etc., but came up "empty."

So, I restored let-off, tuned, and left it at that. 

A year later the client had moved, and I returned for tuning. The hammers were blocking once again! Yipes!

Now, seeing this symptom on another YC has me wondering what's at work here? Can anyone shed some light?

BTW, I've read in past about YC action brackets "growing". 

I've seen that about twenty years ago on a mid-century "Zimmerman" (East Europe/mid-quality). In that case, I had a machinist mill new brackets from aluminum. Nice work, but the orignals were so messed that determining original dimensions was a real chore!

Neither bracket-sets on either of these actions though have the cracks and "bloated" appearance those Zimmerman brackets had.  

Any clues?

much thanks!

Mark Cramer,
Brandon University