Z axis Amplifier Fault on Fadal 4020

[Fudd]

While machining a part today the machine, Fadal 4020 1990 vintage, e-stopped with a Z axis amplifier fault. Several attemps were made to reset with no go. There is a fuse on the Amp card which was blown. Replaced fuse which blew again upon power-up. Is there anything else I need to check before ordering a new Amp card? The card appears to be a Glentex DC servo amp card.

Thanks,

Scott

[Al_The_Man]

Prime suspect, power Transistor.
You may want to inspect the motor, brushes etc, blow out carbon dust and inspect commutator through the brush holder.
if you want to confirm the test just hook the main armature wires up to low voltage DC (auto battery) and to test for excess current.
Al.

[Fudd]

Took the brushes out and everything look great. Call KMAC and talked to Keith. He had me unhook the brown and white wires on the board that go to the motor and check resistance. No resistance, so powered-up the machine and did not get a fault. X and Y move. The board blew the fuse again so we determined it was the board. They did not have one in stock. Call FadalCNC and go a remenufactured one comming.

Thanks,

Scott