A Warning: Be Careful When Installing A BL Touch

I received a Creality BLTouch for my Ender 5 Pro and went to install it. When I powered it up using only USB power everything was fine. When I hooked up the 24V power from the printer’s power supply, I started to see a little smoke from the control board. I VERY quickly killed the power. Jump to YouTube. I found a video from Rick’s Basement wherein he made reference to having to re-order the wires in the 3-wire Dupont connector from the BLTouch. It was for a different board, but I latched onto the idea: check the wiring; make sure it’s correct. I found I had to swap the red & blue wires in the 3-wire connector. After that, no more issues when I powered up.

Fair warning: before powering up a new BLTouch installation, be very sure the wiring is 100% correct. I know, it’s mind boggling to think a simple wiring mistake of an ABL could actually fry a control board, but it apparently can. It seems pretty easy to believe this is a design flaw of the control board. Surely, there should be some kind of protection of that part of the circuit, but nope, there isn’t. Be careful.

You would think the cables would come wired correctly. The 3 wire connector in the RC world is called a Futaba plug, no clue where Dupont connector came from. They are always wired with the Red (power) wire in the center, this eliminates the magic smoke when plugged in backwards.

At least your board didn’t go up in smoke and is still working. Scary stuff!!!

I believe the original design for this plug was made by Dupont Corp: [U]https://www.amazon.com/Glarks-Crimper-Connector-Crimping-AWG28-18/dp/B07VQ6YNSC/ref=sr_1_5?crid=62LP41Y1XE1K&dchild=1&keywords=dupont+connector&qid=1607643425&sprefix=dupont+conn%2Caps%2C193&sr=8-5[/U]

And, yes, I’m glad the board still works. Mind you, it’s less than $50 to replace it.

Yep, sorry you went through this, but tons of people have had this issue and it’s one of the big reasons why you see people have problems with the install. The Creality kit was made for the older 8-bit boards and comes with the extra board and other parts not needed on the 32-bit boards, and it’s also wired differently. Basically it’s their fault it was designed this way. BLtouch units from the Antclabs don’t generally have this problem, but it always pays to triple check.

Especially since it can blow up the control board. It’s completely reasonable to figure that, if the wiring is incorrect, the BLTouch simply wouldn’t work. It’s not reasonsable to think it could blow up the controller. After all, it’s just a sensor; how much harm could it do? For it to damage the board is just poor design IMHO.

FYI here’s the pinout for Bltouch connector, 32bit 4.2.2 board from a Ender 3 v2

Yep. I have the same connector on the new 4.2.7 board I just got. The DuPont connector wasn’t making the kind of contact I wanted, so I cut the connector off and replaced it with a JST that fits the connector properly. You better believe I triple checked the wiring before powering on. Thank goodness, no issues.

Yeah, better crip proper connectors on, than end up with failed prints or a broken printer, because of an end stop did not get triggered. Especially when using max end stops, too.

If you don´t want to change the connectors or want to stay compatible to future hardware changes, You can always do something like this:


That’s interesting, did you make it or is it available somewhere?

If I had a Dupont connector kit I likely would have done something like this as well. I mean, it does involve double connection, but it should still be secure enough. The main thing is the contacts have enough grip.

The connections inside this adapter are soldered. I soldered the black pins into the metal cable clamp of the female white connector and pressed the construct as one piece into the white housing. It will not come loose for sure.

I made them for my GeitPrinter to be flexible with the connectors. I currently use an SDK Board but, when later some other board is required I can use the same wires with or without the adapters.