View Full Version : M8 + RF-901SM settings

2012.12.18, 02:29 PM
Need some settings
With the Airtronics AM module i can get reverse to work somewhat but with the
PN adapter/RF-901SM i cannot get reverse to work at all.
Emailed PN but they have not replied.


2012.12.18, 05:15 PM

I dont know if this will help alot but its the only thing I could find on the initial setting for the RF-901SM. Its geared more towards an EX-10 as the radio but maybe it will get you in the right direction.


2012.12.18, 08:25 PM
No matter what endpoint and trim setting i tried worked. Even with AM module it wasn't right.
I tried to reset in the service menu and messed it up worse. Unusable now.
Oh well i didn't pay much for it.

2012.12.19, 11:42 PM
I never tried the M8 with ASF but with AM you have to play with the the sub trim of the throttle.

2012.12.20, 10:46 AM
Ya even on the helios it needs to be set more forward to work right, which seems opposite of what you would think.

Dont forget that the trigger goes from throttle, to brakes, then nuetral, then reverse and if you miss the order it may need to start over.

Thats why on the helios we use the ABS function to pulse the reverse so we just hold back on the trigger and it cycles through and reverses.

Keep trying different combinations. I'm sure somebody out there has used an M8 with the RF-901SM module and knows what to tell you to try. Keep looking. Good luck.

2012.12.20, 10:52 AM
I gave up on it. Something was wrong with the controller. Bought a futaba 3pj last night

2012.12.21, 12:29 AM
If it helps, I've read multiple posts that airtronics supposedly sucks with ASF anyway.

2015.03.21, 02:55 AM
Resurrecting an ancient thread, but I recently picked up an old M8 for cheap, thinking of using it as a loaner radio.

I also initially had a lot of frustration with reverse not working, but I finally managed to get it working so I will share my settings for anyone who still has this dinosaur of a radio kicking around.

Firstly, both steering and throttle channels need to be reversed in the menu.

After that, the steering can be tuned as normal, though I found that the car physically maxes out with the steering endpoint at around 70%.

Three things need to be changed in throttle settings in order to get reverse working.
Throttle subtrim in the menu needs to be set all the way forward.
Throttle trim using the trim button also needs to be set all the way forward.
Finally, the brake endpoint can be set around 40%. At this setting, the car is almost on the edge of going into reverse. You can set the brake endpoint lower, but the braking power will be very weak when driving. At 40%, it is mostly usable but the braking is still relatively weak.

Tested and working with both the PN adapter and just straight wires, on the modules RF-901SM (ASF), RF-103A (AM), and RF-501A (AM).

2015.03.21, 07:32 AM

Can the M8's throttle trigger's neutral be manually changed? I remember on some older radios you can set the trigger's mechanical neutral to 1/3 reverse and 2/3 forward travel or 1/2 forward and reverse.

2015.03.21, 01:22 PM
KWT, that's a very good point, and I'm not sure whether it's possible. I certainly didn't find anything about it in the user manual.

I think a 50/50 forward/reverse might work, because I did notice that without making any adjustments to the trims and brake EPA, it is possible to make the car go reverse by releasing the trigger, pulling the trigger ever so slightly, then releasing the trigger. It's just not well-controllable.

I'll check the manual again, but if there's no externally-accessible way to change it, I'm not too keen to crack open the radio, because for the rest of my stuff I do prefer a 70/30 forward/reverse.

2015.03.31, 12:44 AM
I've been using M8 radios for a long time now with ASF Mini-z. There is a narrow window in settings to get everything right, but it's certainly doable and very difficult. Yes, the Sanwas being proper racing radios have much more forward travel compared to brake and reverse. I you want to alter that ratio to better adapt to the Mini-z throttle travel, there is no straight forward adjustment for it, but it's quite easy to alter slightly if you just want to open the radio lower segment and add a drop of glue on a plastic piece to make it marginally longer. You could probably also add a small trimmer in parallel to the potentiometer itself to bring the bias point a little more forward.