I was just fiddling around with the wiring on the clawbot as the kids were having some very strange issues with their code, and as I disconnected the motor and motor controller, the male pins snapped. What is the best and most legal way to repair these? Can they just cut the offending male connector and solder on some clipped PWM cables instead? Or is there somewhere to get 2 wire connectors like the ones used in the 393?
I’m pretty sure it’s legal to cut off the connector and solder on an identical one (as long as you didn’t make the wire any longer in the process). Off the top of my head I don’t remember a Q+A thread that *explicitly *allows this, but under the bolded rule It should be legal.
You can get identical connectors from broken motors. If you don’t have any broken motors yourself, the easiest way to get the connectors is probably to ask another team for a connector off one of their broken motors.
Obviously take care to avoid shorting the wire if you make this repair. A short will result in a destroyed motor controller or cortex port. In some cases a motor short can affect other ports on the same cortex, which essentially makes the entire thing useless.
Allright. Thanks for the good start. We have quite a few teams around here so I’ll try that. Meanwhile I think I’ll post this to the official Q&A to see if I can get an official response that allows snipping other wires than those off of the 393s. Thanks again!
This happened to me yesterday. I lifted up the little tabs on the connector and slid the wires out with the broken crimps on the end of them. Then I soldered a bit of paper clip onto the end of the crimp and put it all back together. Took 5 minutes and cost 2 paper-clips!
I guess that was a good “bush repair”. You may want to consider replacing the pins, here is one source.
http://www.hansenhobbies.com/products/connectors/servoconnectors/pt1in_mt/
I just solder on the appropriate length cut from an extension cable to replace the bad connector end, use heat shrink tubing around each soldered point, then another piece of heat shrink tubing around the whole thing. When you solder stranded wire, it forms a stress point where the soldered solid section meets the stranded section, so you must make sure the wires are not allowed to bend near the soldered point.
Thanks for the post and thank you jpearman for the pin source. Our team has also had extreme problems with the Strain Relief (the rubber part that exits the motor) connector. You may have seen this happen to your motors. Our team calls these motors Cortex Killers as right before they break off, there is a high probability of a short. If the motor is plugged into port 1 or 10 the motor can short the port and cause smoke / fire. A small problem can destroy a $15 motor or $250 Cortex.
The team has instituted a new policy that as we remove a new motor from the packaging, we lightly fold over the wire at the strain relief placing the pill size plastic piece on the wire along the narrow side of the motor. Then we FIRMLY WRAP the motor-plastic part with tape to move the stress from the strain relief joint to the newly wrapped point. We use a light colored duct tape (not electrical tape) so that you can write on it TURBO, SPEED or TORQUE. (see image below)
We retrofit older motors as we repair them. I have not found a good source for 2 pin connectors but we use three pin connectors and remove one of the wires. When replacing the entire end, the most economical source I have found is $2.77 for 10 versus $4.99 for 4 from vex. Don’t throw away the third wire as it also repairs the single pin issue as well. (jpearsman’s link is $7.44 for 30 single pins shipped to us for comparison)
Sources
Connectors : here and here - You can remove the third wire and the housing around the male pins to make it identical.
Heat Shrink : here
Strain Reliefs : When repairing motors, we do not replace these as the tape trick seems to solve the issue but you could. I have not sourced the size but here is a good place to start the search.
These obviously also repair 2-3 wire motor controller 29’s …
These items can repair all of your broken pins
https://www.pololu.com/product/1930
https://www.pololu.com/product/1901
https://www.pololu.com/product/1928
and some wire
Wow, there are a lot of alternatives posted here! we usually just snip the end off a 2 wire extension, and put it on the broken motor! these are all very good ideas though! but in a pinch, if you ever need to fix one fast and don’t have many parts, a wire extension will do the trick! 