I've got a 16 Allen-Bradley 700-TBR24 relays that are "sticking". 24 VDC from a PLC card drives the coil, and 120VAC is on the NO contacts drives a .4A strobe light. At times when the PLC digital output is turned off, the relay indicator goes off, but the 120VAC light remains on.
Removing the 24VDC power source from the card/coil does nothing (the light remains on), and resetting the the 120VAC does noting (the light comes back on once 120VAC is restored). The only way to turn the 120VAC light off is to pull the relay from the terminal block. When replacing the relay back into the terminal block the light stays off (as it should).
This phenomena is seen all 16 relays at time to time, so it's not just one bad relay. What is going on here?
