There’s a few controller boards that have soldered-on stepper drivers which makes them cheaper than boards like RAMPS that need stand-alone drivers, but if you burn-up a driver, you’re up a creek.
What about a board with soldered-on drivers that also has holes through the stepper lines on the board so if you burn one up, you can solder in some headers and bypass the built-in driver with a replacement?
(I know you could just replace the soldered-on driver, but I’m not sure my SMD-soldering-fu is up to the task…)
Another plus for soldered on chips is that you will probably not fry them anyway. Most chips fail due to inverted insertion, or power reversal, and safe design practices on the board can prevent both, even if you reverse the input power.
That said, SMD repairs are tricky and best left to the pro’s and the desperate. If we can manage to start making these boards in larger quantities, the unit cost would be low enough to warrant whole board replacements - without breaking the bank.
Smoothie also has the driver chips soldered directly onto the board so the heat dispersion for the chip is significantly improved. Or so the blurb on the website says.
I’ve thought about this before, but breaking-out the step/dir/enable pins is probably a better compromise. It allows you use a beefier stepper driver, lets you use multiple drivers on the same signal, and allows you to bypass a fried driver, though the common pololu-compatible boards will need a breakout board to plug into (like the stripboard ones we used to make to use pololu boards in the Gen3 electronics days, before boards like RAMPS and Sanguinololu).
There are 3 extra drivers worth of pins broke out to dedicated headers. The built in drivers have test points you could solder onto if you find a way to burn one and need 8 total.
