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View Full Version : Athearn AC4400 very noisy on DCC



jeffrey-wimberly
03-03-2007, 08:29 AM
Last night I decided that it was time to put a decoder in the new AC4400. It runs so quiet on DC that it should just whisper on DCC right? WRONG!! I installed the decoder, placed it on the track and gave it power. I've heard electric can openers that are quieter. I worked on it for a couple of hours to see if I could get it to run quiet, but to no avail. At about 10:00 pm I removed the decoder and rewired the unit for regular DC. I was thinking that maybe it's the decoder that's causing the noise, so I installed it in my Proto 2000 PA1. Expecting to hear a high speed can opener I applied the power and to my surprise the PA eased forward and trundled down the main line with nary a sound. Seems to me that the quiet motors of the RTR Athearn units aren't all they're cracked up to be. I know I won't be buying another one real soon. It's funny. I put a decoder in a cheap BB and it runs without a sound. I put one in an expensive RTR and the neighbors can hear it. Go figure.

radar
03-03-2007, 08:59 AM
:D I had the same problem with a athearn gp-38 this guy has a solution to the problem I now have about 2 dz motor mounts that I don't need:eek: http://www.wave.co.nz/~lakewood/F3-F7Project/AthearnChassis.htm

jbaakko
03-03-2007, 09:13 AM
Jeffery, I found that the noisy part of my Dash & F59PHI's was the tips of the ball at the truck ends of the axles, brushing the chassis, it got louder when turning cause it would brush harder. Try checking there.

CSX_road_slug
03-03-2007, 10:02 AM
Jeffery, I found that the noisy part of my Dash & F59PHI's was the tips of the ball at the truck ends of the axles, brushing the chassis, it got louder when turning cause it would brush harder. Try checking there.

Maybe if it's a shell vibration issue similar to what Josh said; it could be that the decoder itself may have been [physically] conducting vibrations from the motor to the shell on the AC4400, whereas it would be quiet if there's a gap between the shell and motor assembly (like when there's not a decoder installed)...just a guess

jeffrey-wimberly
03-03-2007, 11:37 AM
Maybe if it's a shell vibration issue similar to what Josh said; it could be that the decoder itself may have been [physically] conducting vibrations from the motor to the shell on the AC4400, whereas it would be quiet if there's a gap between the shell and motor assembly (like when there's not a decoder installed)...just a guess
I thought of that and ran it without the shell. Same noise, only louder. I've tried two decoders in it and it was noisey with both of them. Both of these decoders have since been installed in two other units where they perform without a sound. This is definately looking like a fault caused by the motor. I've bought two expensive Athearn's and both have had issues that quality units should not have. I won't be buying a third. I'll stick with the Athearn BB's. I put a decoder in one of them and it runs great and with no noise.

radar
03-03-2007, 12:58 PM
check the drive line it has to be as straight as possiable that why i sent the link the gentelman ther shows how to drop the motor down so to straighten the drive line once you remove the motor I could'nt get it back in line till i followed his recomandation

radar
03-03-2007, 12:59 PM
has something to do with the hex drive shaft

B_Kosanda
03-03-2007, 04:30 PM
Sorry, Athearn is junk. All mine have hit the trash can out of frustration with the noisy drive systems. Even the Genesis units have suspect drive systems and are noisier than any other manufacturer. What decoder are you installing? Is it a new model with high frequency drive to eliminate the buzzing? Like a Digitrax DH164?

Bill

jeffrey-wimberly
03-03-2007, 06:05 PM
It's a NCE Silent Running decoder. After I heard the awful racket the 4400 made I pulled the decoder and installed it in a Proto 2000 PA1 where it performed and still performs wonderfully. No noise at all.

One things for sure. I'm not buying any more of Athearn's expensive stuff. I've bought two expensive locos from them and neither one has performed properly. One is a Genesis 4-6-2 Light Pacific that has drive issues and the other is this AC4400 RTR. It wasn't lubed at all, so I had to do that and it smoked it's light board during break-in, on regular DC, so it had to be hard-wired just so it would run. I'm not taking it back either. I'm keeping it as a reminder that I don't want any more of their expensive trash. I have a bunch of BB's that run better than this thing does.

B_Kosanda
03-04-2007, 10:40 AM
You're right on with the comment. At least with the blue box stuff, you knew what you were going to get when you bought it (Price = Quality). Although I must say that the Genesis freight cars are very, very nice.

Bill

speent
03-05-2007, 11:36 PM
Jeffry, I have 2 identical Athearn RTR P-42's. One of them is fine in both directions, and the other is quiet in one direction and really noisy in the other. It sounds like a can opener like you said. Its definitely coming from the motor. My solution- buy a Kato or Atlas next time- LOL