One of my early purchases this year from Athearn is now starting to buzz when it is put under a load and when speed is increased past half way. The transformer I use is the RailPower 1370 by MRC and when the speed is turned up past 60 my AC4400 will start to buzz.
It does not lose power or speed but will buzz and continue to do so until I throttle to a stop and then start back up. Anytime the unit is kept under 60 speed it does not buzz even when pulling several cars.
Anyone have an idea of what the problem might be and how a novice like me can fix it. Thanks in advance
You mean you have an Athearn locomotive that doesn’t have the famous Athearn “growl”? [:)]
It’s highly unlikely that the buzz comes from any problems in the power pack. If it was caused by a filter letting through a nasty pulse, it wouldn’t be limited to particular speeds and loads. Besides which, the RailPower 1370 is not exactly known for its exotic pulse generation circuitry. [:)]
Have you taken the shell off and closely observed the locomotive when it is buzzing? I’m suspecting a loose motor and/or mount.
I don’t suspect it to be the power pack because I have six locos and this one is the only one with this sympton. Even when I run the loco by itself with no rolling stock above that 60 speed it will buzz. I guess I can try to take the shell off and see if I see anything or I’ll just keep doing what I’m doing and run my trains at 60 and under.
A buzzing sound is usually a vibration. Try to run the engine under the same load without the shell on it. I suspect the shell may be vibrating at a certain frequency. Sometimes a strip of tape inside the shell will cure it (it did on one of mine). Also the shell mounts may have loosened up a bit. A small shim of tape strategicaly located on the frame might help as well.