New Mychron 5s problems

Hi everyone,

My mychron 5 is giving me trouble. It reboots several times during a session. The screen freezes at times and I have seen the LCD scrambled. Suddenly it all comes back to normal and working. I have updated the firmware (more recently I used Race Studio beta 3 and downloaded the newest firmware). Any suggestions? Should I reset it?

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Call Aim Sportsystems.

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Thx Greg. Just saw a post here regarding checking the RPM cable. If it disconnect, the unit can go off. I will check that tomorrow and if persists, will definitely call them.

I had the same problem. Its the rpm cable that needs attention.

Also read this


To be on the safe side, use the firmware from the production RS3 and not the Beta version. The Beta version has beta firmware that may not be released as an official release. I’ve asked already. Then call AiM support.


Thank you so much! Will definitely check the cable and the spakplugs!

Makes sense. Will check cable and if persists will find out how to downgrade the firmware! Thx!

I’m on the newest firmware, without any problems , after I got my rpm cable, sorted out.

new firmware fixed my EGT readout issue where it wouldn’t read above 999 on the live display.

Also before new firmware it started reading RPM values that were like half of what they should have been but not quite half because when I change the multiplier to 2x it read like 1.5 times what it should have been. This was also solved with the firmware update.

However, now the predictive lap timing works when it wants and doesn’t work most of the time. Like literally 5-6 laps into a session it may start working, and on other sessions it just never start working. Annoying there seem to be some bugs with the new software, hopefully they get it all sorted.


Okay, changed the wire (it was touching the exhaust and got burned). But then it keeps turning it off and the led to the left turn red. Cant turn it on again.

I’m having the same issue with my Mychron5S. I recently upgraded from the 5 to the 5S and would get issues with the display not updating properly after each lap, scrambled display, or it not updated at all, etc…This is all with the exact same rpm cable setup as I had with the 5 without issues. At my last race it has now failed to turn on even with a charged battery. I’m now sending it in to AIM to get repaired as it’s probably a hardware issue. I think it’s worth giving them a call and possibly sending yours in too.

How do you have the cables for the gauge routed? The RPM cable should be routed by itself and tie-wrapped to the chassis.

The rpm cable runs along the chassis tubes with 3D printed clips I made to organize everything. So it should not cause any issues and have never had issues with multiple Mychron 5 devices. When I swapped to the 5S I simply disconnect the cable from the 5 and put it on the 5S.

I really believe it’s a hardware issues especially since it now fails to turn on even we pressing ‘ON’ manually and the device is off the kart. Rafael also mentioned something similar. Luckily AIM should repair under warranty so I’m not too concerned. We’ll see.

Mine was also running through the chassis. I am really lucky: Track owner was super kind and let me use one of his units for the day: no problem at all. So it’s not the installation. It’s the unit. He will reset the unit and if still giving the problem we will replace or sent it to AIM for repair.