I'm helping a customer sell his YC G-185, made in 1986. It seems very nice, plays well (though could use a regulation)... can anyone tell me how to recognize whether it has the expanding action bracket problem? Does it affect playing? Or is it only obvious when trying to remove the action (which I haven't done yet)?
The most common symptom is hammers blocking against the strings. If they aren't blocking, check to see if the hammer let-off dowels are turned way down to compensate. The defective brackets were gray in color. The replacement brackets are gold in color. If they are defective, and you remove the action, the brackets may break as your try to fit the action back in place. If they are expanding, you may even have trouble removing the action. If you try to remove the action, and it seems like you have to pry it out of position, don't go any further, or you'll have a completely unplayable piano until you replace the brackets. You can call Young Chang to see if the serial number falls into the defective bracket category.
You can also search Piano World for "Young Chang expanding action brackets". There have been several threads about this in the past, which will give more information than I've posted here.
Your key clue is that the action could use regulation... Measure the action spread (center pin to center pin - wip flange to hammer flange) There is a specific target number - if too large, the the brackets are expanding. I have seen some that shift very slowly over time and still come in and out of the action cavity just fine. The regulation just seems to shift a bit.
I can't remember the action spread number - maybe 113.5 mm? Someone else probably has it handy...
Pre-1991 actions have a 112.5mm spread. This is info from the Y-C manual.
Measure with a spring divider.
The following information is from the paperwork sent to me by Young Chang with my first set of replacement brackets:
"Symptoms: Blocking hammers, unstable regulation, excessive spread measurement, loose let-off dowels (over adjusted), checking problems. Brackets may not show any sign of defect, but cracks in the finish are common."
"Action spread should be set to 112.5mm"
"Pianos newer than 1992 action spread is set to 113.5mm (action let-off rail at 90 degree angle)"
Thank you all very much for sharing your experience and info. I will go back and investigate further.
Call Sam at Young Chang at 657-200-3490. Give Sam the serial # and he will tell you if the brackets are in the affected batch. He probably has records on which serial numbers have been replaced as well. Young Chang, to their credit are still sending replacement brackets at no charge. The latest brackets seem to change the location of the stack enough to change hammer alignment with the strings, so I've had to do more work aligning hammers to strings, including shimming the action in some cases. Time to regulate depends on if anyone has tried to regulate the old brackets - because doing so requires reversing everything they did once the new brackets are on. String grooves on the hammers should be removed to aid in hammer alignment.
Got it--thanks so much, Bob. I'm going out to take another look at the piano this morning but will definitely make this call also. Much appreciated.
Just FYI I spoke to Sam at Young Chang this morning, who told me the problem did not develop until 1988. I also examined my customer's piano and found it to be perfectly fine and the action spread is exactly what it should be, 112.5 mm.