I have a wire EDM machine, Fanuc Tape Cut Model I (Matra). Quite old but was performing excellent until the last week. The machine no longer has the appropriate cutting speed at the settings where it used to work normally.
The wire is breaking and sticking. When the 2 uF capacitors are connected, it seems like the machine doesn't have enough energy to sustain it. The initial suspicion was that the capacitors were faulty, but measurement confirmed that they are functioning correctly, all were fine.

After that, the on-time and off-time switches that affect the impulse creation on the wire were checked. Their previous settings were on-time 4 and off-time 2, which the machine previously worked normally on, achieving the desired speed. Now, at the same settings, it has 30% of the desired speed. A comparison determined that the switches are functioning correctly.

By changing the on-time to 8 and off-time to 4, a visible change can be observed, the machine cuts faster, but still not as it did before. The question is what could have caused the change in cutting speed even though the parameters haven't been changed.

What to pay attention to, whether the pulse generator is providing the appropriate pulse or if something else is the problem. The wire tension, cooling, voltage, and current looks fine.

Any advice will be helpful.

Thanks in advance