I am new to this forum and a novice to the RC hobby. I recently came across my old Tamiya Blackfoot monster truck from roughly twenty years ago. I ran it a couple of times in the driveway with no problems or strange noises from the motor. However, after upgrading to a Dynamite Tazer 15T Electronic speed controller and a Futaba 2PH radio... The motor sounds like an old time telegraph. Beep, Beep, Beeeeep, Beep, Beep, Beep when the radio is turned on. Both short and long sounds. The sound is definetely coming from the motor, as it dissappears when the motor is disconnected (OR when the radio Tx is turned off). The motor still works fine & the truck runs as it should, but that noise is very odd. I reinstalled the original mechanical speed controller and the noise went away. Could this be a radio interference sound ? The motor does have One capacitor on the outside of the motor and this is totally stock. Here is what I am running ... Tamiya Blackfoot, Parma stock 26 turn motor, Dynamite Tazer 15T Electronic speed controller, Futaba 2PH 75Mhz AM Radio. Any help with this issue would be greatly apprieciated.

Did you setup the speedo? Sounds like either:

1. You are getting interference. Whether it be due to the radio, wire routing, or other.

2. The speedo is not correctly setup. You can verify this by watching the lights on the speedo as you hold the radio at 'neutral'. If you aren't touching the trigger on the radio, but the light(s) are indicating something other than neutral on the speedo, then the motor is recieving either the forward or reverse current from the speedo.

Don't quote me on this, but don't Dynamite speedos and Duratrax use the same setup routine? I know the DT that I had required setting every time I turned the radio on.

I have, in the past, used the trim on the transmitter once a speedo is setup. Once everything is setup, turn the throttle trim on the transmitter until you know the speedo is in neutral (watch the lights). This was a common tip used on older AM radios, as they had a very small neutral point and the slightest bump or movement would put them into forward or reverse. This can also be attributed to 'drift' of the radio signal.

Thanks, SuperXRAY .... You nailed it. The throttle trim was just a little off causing a weak throttle input to the motor. I found this by following your suggestion of watching the LED on the ESC. Sure enough, it was flickering with the throttle in neutral. A simple trim adjustment and the noise is gone. I can't believe I didn't try something that simple before posting for help. Anyway, Thanks Again !!!!

No problem, glad to help.