[pianotech] Stuck solenoid

[Ron Nossaman]

On 7/25/2012 9:02 AM, Dean May wrote:
> I’ve also found another cause: the rubber tip binding against the bottom
> of the key. This problem crops up when the bottom of the key is at an
> angle, or the plunger is not 90 degrees to the bottom of key. As the
> plunger comes up, the angle becomes more acute, the rubber tip locks in
> place and won’t slide back to rest position. I’ve applied thin CA glue
> to bottom of key, sand with 400 grit paper to make bottom of key glossy
> smooth, then apply judicious amount of lube.

I've found something similar in Disklaviers a couple of times. Not 
because of anything being at an angle, but because of that nice clean 
soft grippy silicone rubber tip on the solenoids. They stuck on release 
of shift, with notes down. Dust accumulation would have probably 
eventually "fixed" it, but a light dusting of Teflon to the tips took 
care of it immediately.

Ron N