Just my experiences to share how I fixed my Bulldog Lite extruder.
My Bulldog Lite extruder did reasonably work well on my RAMPS1.4 set up with A4899 step sticks with the occasional ticking sounds. The issues started when I changed filament and I could not find the sweep spot on the step stick pot meter and extruder tension screws. After reading about the new DRV8825 step stick and its features (higher driver current and 32 microstepping) I decided to give it a go. Because this step stick uses 32 microstepping you need to change the steps in the firmware or change the jumpers on the ramps board. I decided to leave the config as is because 16 or 32 mircosteps is probably not going to make a difference on a direct drive extruder (on X- or Y axis it would).
Two of the three jumpers need to be removed under the step stick insert which are located next to each other and pointing to the power connector side of the ramps board. That leaves one jumper on position 1 (furthermost position away of the PCB edge). The new step stick looks different from the old one and the pot meter is located on the opposite site so caution to insert it in the correct position (don’t assume the same orientation as the old stick). The DRV8825 does not require a head sink but it is recommended.
The results so far are fabulous: no more ticking, high precision prints and the extruder tension screw can be tightened to have good grip on the filament. The pot meter on the new step stick is not critical (so no critical sweet spot). The resolution of printing has gone from 200 to 50 micron (with 0.4 mm nozzle/PLA) and I will post some pictures soon after some more printing.
Hope this tip will help.
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My latest print with the improved electronics!
