The stepper drivers that come with the A5 are the cheap and cheerful A4988. This drivers are incredibly low-cost, and are generally quite reliable and robust. However, they do fall short in a few areas:

• They are incredibly noisy
• They can cause salmon-skinning on print surfaces
• They are only able to do 16x microstepping

Fortunately, the MKS Gen L motherboard on the A5 and A3S has socketed stepper drivers, which enables us to replace and upgrade the drivers. One option comes from a German company called Trinamic, who make a range of more advanced stepper driver chips. These chips can be swapped in to overcome ALL the shortcomings of the A4988 listed above, and to add some additional smart features too. All Trinamic drivers offer 256x microstepping, and are much quieter in operation too.

The current range of Trinamic drivers available is listed on the manufacturer's website, but only some are available in ready to go drop-in modules. The popular options for 3D printing are the TMC2100, the TMC2130, and the TMC2208.

A brief comparison summary of these drivers is listed below:

• TMC2100: A simple option that offers two operation modes, SpreadCycle or StealthChop.
• https://www.trinamic.com/products/integrated-circuits/details/tmc2130/TMC2130 Same as the TMC2130, but also offers additional operation modes, as well as additional functionality like stall detection.
• TMC2208. Similar to the TMC2100, but this chip offers a UART interface and a more sophisicated StealthChop 2 operation mode. This chip is also easier to install, and can even be used without any firmware changes at all!

For each of these driver modules, details about where to buy, and how to install are listed below.

• Gearbest
• Banggood
• Aliexpress
• Amazon USA

Installation is fairly straightforward:

• Remove old drivers
• Remove all jumper connectors underneath the old drivers
• Install the new drivers
• Add a fan to blow over the drivers
• Invert the direction of the motors in the firmware

NOTE: the orientation of the new drivers is different to the factory ones. Make sure you match up the pinout with the old drivers to ensure you insert them correctly.

There is a video guide of how to install the TMC2130, but the installation of the TMC2100 is the same.