3-1 Error Code. Cart won’t move.

[yurtle]

Buy transistor, open controller, unsolder bad one, solder good one.?

Note orientation of the "bad" transistor.

[biphase]

You will need a thin blade like an Xacto knife to open the controller. Not a pointed blade but #18 chisel blade. The cover "snaps" onto the baseplate along both sides. Set the controller on its side and insert the blade between the plastic cover and the baseplate and pry the cover upward until the snap releases. Repeat on the other side and remove cover.

[Jonathan08]

Attachment 171624. Am I pointing to the correct part? Also attached a pic of the entire controller.

[Jonathan08]

Does this look normal? It’s a close up from underneath J3. You can see it in the full picture I posted of the controller above as well.

[biphase]

Yes, that is normal. You are seeing solder flux around those pins that connect the logic board to the base unit. Looks a little messy but not a problem.

[Jonathan08]

Ok that’s good to know. Am I pointing to the correct part that needs replaced in the other pic?

[biphase]

You are pointing to the transistor that needs to be replaced. When you orient the transistor so that the three leads are pointing toward you, the leftmost lead is the "gate", the center lead is the "drain" and the lead on the right is the "source". Set your meter on the diode scale and place the black lead on the center lead (drain) and the red lead on the right lead (source). You should read about 0.5 volts on a good transistor. What reading do you get?

[Jonathan08]

Here is what I get on the reading. Nothing.

[biphase]

That would indicate a bad transistor. Try the same test on a new one and you will see the difference. If you plan to replace the transistor, it can be done from the top side of the board. No need to separate the logic board from the base unit but care must be taken not to damage the copper traces that the transistor is soldered to. I would use a pair of "nippers" to cut the three leads individually and remove them one at a time. If you are not experienced with electronic component soldering and desoldering, you may want to get some help in removing and replacing the transistor.

[Jonathan08]

I am not familiar and will be seeking out help. Thanks for the tips. Anything else you can think of that would be useful I will take as well. 😂