Re: VMC 760/22 toolchanger problem
The relays on the TLAUF or LCTLAUF are solid state and typically leak or short. They are the row of black devices maybe 1/4 inch by 1 inch by 2 inch.
I have seen the arm back short and thus the arm could not come out. And it does overcome the brake. I have seen the brake wear out and then the arm drops after the power shuts off losing the arm back proximity switch. Also check the arm shock absorbers. They are small mechanical devices. You can refill them but if the seals are gone, the oil leaks out.
Take the board out, turn it upside down and measure the resistance of the two output pins. Check them all. Usually they will measure over 3 mega ohms. You may find one with a lot lower resistance. Replace that one.
You will need a solder sucker to get it out. These relays are available in a 3 and 5 amp variety. Of course get the 5 amp.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)