Is there an easy way to check the bridge rectifiers?

With the power to the machine off, connect the red lead of the digital multi tester set to the diode test function to a terminal number 39 on the machine. Connect the black lead to the following wire terminals one at a time, #11 and #20 for the X axis rectifier, #13 and #21 are for Y, #15 and #22 for Z . The meter should read .5 to .7 between terminal 39 and each of the above wires. You have just checked the negative half of the bridge rectifiers.

To check the positive half of the rectifiers starting with X, connect the black lead to fuse FU12 then connect the red lead to #11 then #20. To check Y connect the black lead to fuse FU13 then connect the red lead to #13 then #21. To check Z connect the black lead to fuse FU14 then connect the red lead to #15 then #22. Each of the meter readings should be .5 to .7. If any of the readings show either open circuit or short circuit you will have to replace the rectifier.

To check the 24 volt or 56 volt rectifiers you will need to follow the directions below to get access to the back of the bracket that the capacitors are mounted to.
The 56 volt wire numbers to check are as follows:
Red lead to wire #39. Black lead to #34 then #35.
To check the positive half connect the black lead to wire #75. Red lead to #34 then #35.
The 24 volt wire numbers to check are as follows:
Red lead to wire #39. Black lead to #36 then #37.
To check the positive half connect the black lead to wire #38. Red lead to #34 then #35. Each of the meter readings should be .5 to .7.

How do I replace a bad rectifier?

With power to the machine off, disconnect the red and white wires number 3 and number 2 from the right hand end of the terminal strip above the regulated power supply.
Remove the four allen head screws that hold the mounting frame for the capacitors to the cabinet.
Roll the frame out with the capacitors down.
Then remove the allen head screws that hold the heat sink in place.
The X, Y, Z and 56 volt bridge rectifiers are mounted to this heat sink.
The 24 volt rectifier is mounted directly on the left end of the mounting frame.
If you are just going to replace one rectifier, you can identify it by the wire numbers on the terminals.
Be sure that you use heat sink paste on the bottom of the rectifier.