Neo 550 broken encoder wire

Two wires broke off the encoder connector on one of our Neo 550s. I found another thread on this that had several links for parts; however the lead time for the them vary from 11 - 34 weeks.

Anyone have any other suggestions? We are replacing the motor for now, but doing this long term is not sustainable as we don’t have the a budget the size of the Federal government.

Also, how do you work on these connectors - they are so small.

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This will require a little bit of wiring skill. Contact REV or search the documentation for the part number of this molex housing or maybe summoning Greg will help.

@Greg_Needel, are you able to provide the part number of the crimped connectors for this molex housing?

Then you will need to order the appropriate metal connector and recrimp them to the broken wires. From there you remove the old metal connectors that are still in the molex and reinsert the new crimped connections. The crimp job is pretty critical on this, as the metal connector has a tab that helps it stay in place in the plastic housing. I’d recommend watching a few tutorials on doing a proper job, as the length of stripped wire is important. This isn’t a quick fix, but probably better than the 11 week lead time.

While not easy it is possible to remove the terminal from the connector, carefully open up the barrel of the terminal and recrimp onto the wire. I’ve had to do that in automotive applications before. Not easy at all with the very small terminals in this case.

Another option would be to snip the entire connector and strip and solder the wires to this board (paying close attention to wire order, of course):

Then you can connect it to a SPARK MAX with a separate cable:

I’d test thoroughly and heat shrink it all before putting it on a competition robot, but as a spare or to keep an older robot running it’s a good look.

How’s this solution:

We purchase the extension cables, cut the end off of the the Neo and wire to wire solder to the extension cable

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That is probably the best long term solution. Stagger your splices so that it doesn’t get so bulky in any one spot. In other words spread your splices out so that no two splices in adjacent wires overlap.

Tape a reference line on both cables. Then cut the first wire at +1 -1 from the reference point, the next at 0, the third at -1 +1, 4th at +1 -1, the 5th at 0 and 6 at 1- +1.

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Probably valid, though I find wire-to-wire soldering to be way more trouble than it’s worth (especially when the REV breakout boards can be had for less than a bottle of soda at a gas station). We use a lot of solder-seal wire connectors and lever nuts at work instead when we can’t or won’t go to a board. If you do have to solder, heat-shrink it thoroughly to ensure it’s well-supported mechanically.

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One should really reterminate all the wires. The broken wires are guaranteed to be shorter after stripping them to crimp on new contacts (or recycled contacts). Thus they will be under tension first when the bundle is pulled, leading to them breaking again.

Due to the design of the connector and the small size of the wires, it is best to add some strain reliefs at both ends of these cables near the connector. At each end, the wire bundle should be secured to whatever the connector is plugged into (SPARKMAX or NEO).

Unfortunately, the connector chosen for this application was designed to be as compact as possible so it doesn’t have anything to pull on to disconnect it, leading one to have to pull on the wires, generally a No-No in electronic equipment. I recall seeing some post here on CD about someone advocating using a small screwdriver to pry the connector body out of the socket when disconnecting the cable. This would allow one to avoid pulling directly on the wires to disconnect the cable.


One of the kids had a great idea to put hot glue on the working Neo connectors to make them more robust.

We received the extender cables and immediately noticed the way the wires are terminated into the connector is made way more robust than the way the Neo wires are - looked like a ribbon cable termination. Why can’t they do that with the Neo wires?

I hope someone from Rev is reading this.


IIRC, because REV is using stock components with industry-standard connectors. FRC is not exactly industry-standard application; usually you don’t want to disconnect/reconnect nearly so often.

I hope this is improved in later iterations, but for now hot glue is good idea.

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Thank you to the community for providing some solid recommendations in this thread!

Great question! The only difference between the extension cable and the NEO 550 is the wire gauge (smaller for the motor), and the wire bonding (bonded for the extension cable). The termination on both are JST PH housings and crimps.

On both the NEO and NEO 550, the sensor wires snake up through the stator, to the hall sensor circuit board. We were able to increase the wire gauge on the NEO after its first manufacturing runs, but that wasn’t possible with the smaller NEO 550 geometry.

There are two main standards for sensored brushless motors in the hobby market, the JST PH and the even smaller JST ZH. When we were designing the SPARK MAX and NEO, the ZH was more prevalent, but we chose to go with the larger PH.


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