I've been asked to work on a Fadal VMC 5020A year of MFG 1997. I know very little about the machine and have not been able to find the manual for it. It is experiencing and amplifier fault.
Upon investigating, I noticed that there were 3 devices in the electrical cabinet that appear to be servo amplifiers with a part number of SMA-8520-3. Two of them had green lights illuminated and one had no lights illuminated. I quickly realized that there was a 20A incoming fuse in line with the B+ terminal of the amplifier and that it was blown. I replaced the fuse with a new one which resulted in another blown fuse. With this fuse now removed, I measured the resistance between terminals B+ and B- and found it to be less than 2 ohms. Upon removing the fuses from the other 2 amplifiers, I performed the same resistance measurement between B+ and B- on the other two amplifiers and found each to give a reading in around 5k ohms if I remember correctly. All measurements taken with the power off.
In addition, I've noticed 2 other devices which have "Advanced Motion Controls" written on them. These two devices are also labeled as servo amplifiers. Upon powering on the machine, I see that one has an illuminated red light while the other does not. The fusing here seems okay but its unclear to me what these actually do since there are only 2 of them.
I suspect that the SMA-8520-3 that keeps blowing a fuse is to blame here for the servo amplifier fault but am unsure since there are two sets of hardware that seem to be called "Servo amplifiers". Ill attach photos of each set of amplifiers mentioned.
Any insight on the issue would be appreciated.