How to check brakes op motors are ok

With the robot in standby (arm power off) try to move each axis by hand, you should not be able to move them.
Operate the brake release (row of rubber covered buttons) if fitted to release each axis, NOTE be very careful when operating axis 2 and 3 as could cause injury!.

This is not all stories.

We have 2 difference brake line for each axis separately.
Brake PB (is shown by RED line in the attached picture): It means when the robot is stopped you can release the axis brake by push button separately.

Brake Release (is shown by BLUE line in the attached picture): command of brake from computer and contactor unit in normal operation condition. Like Robot Jogging in manual mode or program execution in auto mode.

So there is a little difference to check s the motor brake, sometimes break PB is working well. But in normal operation we get trouble with motor break, better way to check brake axis is this :we put our ear on the motor and we drive the robot via teach pendent in case of brake healthy we hear click voice from the motor or check brake circuit diagram according your robot drawing.