View Full Version : Signal problem with my RF901-SM Mini-Z 2.4ghz module for Helios

2008.12.14, 02:18 PM

I ordered one of the first RF901-SM 2.4ghz modules for Mini-Z in the US, and I have had an intermittent problem with the signal strength or something to that effect with it. I use the module with an EX-10 Helios and I am able to bind the Tx to the car without any problem (Everything the instructions say should happen does). But I suffer from a lot of glitching within minutes of driving. Although the binding process works, I still don't completely rule out that there is some kind of binding issue though between my module and my cars.
I also own one of the first US-released KT-18 Tx's and I have absolutely no issues whatsoever when I use this Tx with my 2.4ghz Mini-Zs. The cars bind to the KT-18 perfectly and there is no glitching at all. The thing is I prefer the feel and functionality of my Helios Tx.
I would like to know if I should purchase a new RF901-SM 2.4ghz MINI-Z module for my Helios? Could there be a problem with my RF901-SM module and that is why I am having problems using it with my Helios? I put up with the glitching for a long time because I just wasn't sure if it was me, but now I am positive it is something to do with my TX or module. And seeing my Helios is working fine, I suspect the module is the culprit. I just would like to ask someone from KO if replacing the module is a good idea, or if there are other possibilities for this problem I'm having? Has there been any precedence with this kind of issue with early US-modules? Or any issues with using the EX-10 Helios with the RF901-SM Mini-Z 2.4ghz module?

I would greatly appreciate your help and input with this issue. Thank you for your time!
- Lawrence

2008.12.15, 12:00 PM
Check this thread http://mini-zracer.com/forums/showthread.php?t=30342 to make sure your settings are correct. If they are, you should send your Tx along with your module in for service with a description of your problem.

2008.12.15, 12:39 PM
KO Propo staff - I did not see the thread on "2.4ghz TX settings". Thank you for pointing it out. I just tried the settings you recommended for using the RF901-SM 2.4ghz Mini-Z module with my Helios and it seems my cars are responding as they should - No "loss of signal" issues or glitching so far!:D

If the glitching and signal problems do arise again, could you please post info on how to send my Helios & RF901-SM 2.4ghz Mini-Z module in for service and to what address I should send my equipment? I just want to be sure I send my Tx & module to the right place should it need repair.

You help is greatly appreciated. And thank you for the fast reply to my question!:D

Best Regards,
- Lawrence

2008.12.16, 12:08 PM
Lawrence- Glad that solved your problem. If you ever have problems with your Tx or module, you can send it to KO PROPO America for repair service.
Just fill out the service request form when sending in any items. This form and our address can be found on our website under Support->Repair Centers.

2008.12.16, 12:17 PM
Thank you again for the info.
Happy Holidays:)

Best Regards,
- Lawrence

2008.12.18, 08:52 AM
KO Propo Staff - Sorry to bother you again but it's back! Once again I am suffering from glitching with my 2.4ghz Mini-Zs with my Helios + RF901SM 2.4ghz module for Mini-Z.:(
I have used the settings you recommended:
"It has been brought to my attention that when using the 2.4GHz module you must have the following settings in your Tx.

1. Steering Travel Max 70
2. Steering Balance Max 70%
3. Throttle High Point Max 60
4. Throttle Brake Max 60
5. Quick ST & TH in the EX-1 UR cannot be used."

I have my Steering Travel set at 69;
I have my Steering balance at 67 for "Right", and 68 for "Left";
I have my Throttle High Point set at 59;
I have my Throttle Brake set at 59;
And I have Helios so the "Quick ST & TH in the EX-1 UR" doesn't apply.

I can get the Helios to bind to the cars. Then I turn on the Tx, and then the car. All seems to be good. Then within a few minutes the throttle response becomes glitchy and stutters, and the steering becomes twitchy and turns on its own, making the car undriveable. I have tried re-binding the cars again and again and the problem still occurs. The Tx batteries are brand new, no problem there. And when I change the module to my AD-Band module, the Helios + AD module works as it should with my AD-Mini-Zs.
Also, again when I bind my KT-18 to any of my 2.4 ASF Mini-Zs, the KT-18 and 2.4ghz Mini-Zs work flawlessly - No glitching, no twitching.
So the problem I suspect is with the EX-10 Helios or with the RF901SM-2.4GHZ MINI-Z module.
One thing I would like to know: Under where the module goes intot he back of the Helios, there is a small white switch that goes up and down. Down is "Normal" speed, and Up is labeled "H" for high speed response. DOes it matter which position this switch is in when using the 2.4ghz module with the Helios for Mini-Z? I have the switch in the "H" or up position right now. Also, how many channels should the Helios be set at for 2.4ghz Mini-Z use, 2-channels or 3-channels? I have my Helios set at 2-channels.
I am contemplating purchasing a new RF901SM 2.4ghz module for Mini-Z and seeing if that is the problem. I purchased my Helios in early 2007 (Jan I think) and I don't know if there is still a warranty on it, and even so if I ship the Helios + RF901SM-Mini-Z module to the service center in CA I will be without the Helios for a long while. And if the repairs are noi covered under warranty, between shipping costs for the Tx+module and repair costs it may be worth it to invest in a new module and possibly the EX1-UR Tx (Although I really love my Helios, it's a great Tx).
Two other questions I have: Would a model "Reset" of the Helios make any difference in this matter? Is there a Tx full reset I can perform to try? And second, is the EX1-UR better suited for use with the RF901SM-Mini-Z module than the Helios, or does it not make a difference between the two Tx's?
I am sorry for the long post, and the many questions. It's just this problem is driving me crazy! I thought I had the problem fixed, I don't know what happened. Any help you can offer I would greatly appreciate from you KO Propo staff. Thank you for your time! I hope to hear from you again.
Best Regards, -Lawrence

2008.12.19, 12:02 PM

I would suggest sending (to KO PROPO America) your Tx with the module. It might be that the module pins on the Tx may be damaged (solder joints to the PCB). The modules are still rather new and we will warranty it if you have a copy of your receipt and it was purchased in the US.

There is no master reset that you can do to the Tx (only we can do that). You can reset each model memory but you will have to reset the setting for the Mini-Z.

The Mini-Z will only use 2 channels so trying to use the third will not work (no functionality). You can set it to 3 channel in the High response mode for Super HSR. The Mini-Z should work in the Normal, Super and Advanced HSR modes.