@chipixero If you have an Eleks machine and laser the answer is yes, in fact it supports TTL/PWM which is the ideal setup. The older lasers with 2-wires are non-TTL but they may still support PWM depending on the laser driver. All controllers support PWM because it's a built in function of the Nano microcontroller.
@Josh-Gates If it's missing commands (due to buffer overrun) you will get spurious movement and what appears to be missed steps. I'm not familiar with the method you are using, so perhaps you have some other issues.
Yes I'm quiet sure it is a failing diode too, I bought a Z axis that I received yesterday so I tried it. Impossible to cut 5mm plywood after 12 passes and when I break the wood on a line to see how it burned it is totally irregular : some parts are burnt on 4mm and just next to these parts it can be burnt on 2mm. I'm trying to see with banggood but i'm not waiting a lot from them as they are not even reading the explanations in my email... Anyway thanks a lot for your answers.
The XY motors need around 1A, so you have 4A remaining. The 555 motor needs ~2A for full speed without load, but could exceed 8A at full load (although it would get hot fast and eventually burn out).
I believe the Eleks board (PCB traces) and MOSFET would fail at full load before the motor, if your power supply could even provide enough current without shutting down.
If you care about speed control, you'll need a dedicated motor controller with TTL input. If not you could use a relay. T2Laser supports spindle delay to allow for it to start up before any load is applied, this really helps due to momentum.