CHNC 3 Spindle Brake

Hello,

Odd problem with CHNC 3. (1994/1995)
Spindle Brake is not releasing.
If machine is left in JOG Mode and Spindle Free button is pressed: After some time the brake will release and machine will function. (But can still stick if left idle in Auto Mode.)

Seems like some kind of relay or electric/pneumatic switch is sticking - semi working.

Machine has been running fine in the same place for 20 years.

Anyone ever seen this problem before?

Thanks!

Gummed up cylinder maybe? If an air cylinder maybe dry and needs oil?