I have a spektrum dx3s radio with sr3300t rx, the radio and temp sensor work great, but I cant get the rpm sensor to work, I installed it exactly how the directions say on my 1/10 scale e-revo, the mount I made is solid and I have it aligned perfect with the little shiny sticker on the black plastic spur gear, it just wont read anything at all on the radio like it's not even hooked up, I was wondering if anyone else was having this problem, or maybe if my sensor is just bad, idk I've never hooked this up before and their is no troubleshooting info on this anywhere so I'm asking, I spent about 4 hours making a mount out of aluminum and getting it aligned perfect, and about 2 hours trying to figure out whats wrong after, I know I did it rite, I was just wondering if anyone else had this problem and what they did about it cause I'm no where near giving up, I just dont know what else to do, thank you

Not much of a help, but after spending 2 hours hooking my RPM sensor up, I took it off after realizing that at no point in time am I going to use it.

That sensor needs to be close. Like 2mm or less.

kinda figured that, and I'm now realizing that I wont use it either, just thought it would be cool to have, thanks

Hey are tricky things to install. Not worth the hassle, really but fun to see the speed/RPM.

There are a few things you can do, well that worked for me.

Get the sensor as close as possible as it works on reflection of an IR beam.
Make sure it's working, cameras can pick up the red dot. When I installed mine I just used my phone camera.
Make sure the sensor is the right way up. Might sound stupid but the correct orientation of the PCB will help. That is just a guessing game.

Good luck.

thank you very much that helps alot, they really should include better instructions with that kind of stuff