Buzzing (ground loop) with TMCC operation!?!?!

[MCF]

Set up my first set last week - Lionel Black Diamond Freight. Last night I set up TMCC - Cab-1, TMCC Lock On, Command Base and Transformer that came with the train set. I have checked everything twice and am having a buzzing coming from out of the engine speakers. It did not occur while operating in conventional mode.

The buzzing is present all the time and it is coming out of the speakers...when the volume is up, you can't hear it but when your turn the volume down using the CAB-1 it is there and it is pretty loud....loud enough to where you wouldn't want it sitting in the same room with you. The only way to get the buzzing to go away is to turn down the manual volume knob on the engine, which is not an acceptable solution because you lose all your sound. This problem didn't exist with conventional control...only since I hooked up TMCC.....any thoughts!??!! I have actually unplugged everything else in the room to see if something was causing a ground loop or something with the engine. All lights on the TMCC Lockon, transformer and command base are green. Everything else with the TMCC seems to be working fine. Per a local authorized Lionel dealer, the engine should be completely silent after going thru it's shutdown sequence....

 

[jim currie]

is your lighting in the room florescent ?

 

[MCF]

Nope.....

No fluroscent lighting....I have an aquarium in the room and my entertainment system...I had the engine sitting there buzzing and unplugged everything and no difference. I also had everything plugged into a surge protector strip and tried different combinations of using the surge protector and directly to a grounded outlet and no difference......

 

[jim currie]

is the breaker for that room separate for that room only or is there other areas of house on same cicurit if so you might be getting feed back, that is assuming you are getting a 60 hz buzz. you might also try a filter on the power to your unit.

 

[ezdays]

You are in all likelyhood picking up what we used to call "60 cycle hum" (a long time ago). As Jim was trying to get at, this frequently comes from florescent lights, but as you suspect, a poor grounding problem can cause that as well. The hum is "noise" and at a constant level from your control unit since you can drown it out by increasing the control volume (it doesn't go away, just gets overpowered by the audio signal) or by turning down the volume at the engine which turns down the volume for the signal as well. A surge protector isn't going to make any difference since its only job is to squelch spikes on the AC input. You could have a bad earth ground going to your power pack or to some other piece of equipment. You may also have a ground where there shouldn't be one, like maybe one rail is grounded and shouldn't be. If that isn't the case, maybe grounding one rail will do the trick. As Jim suggested, sometimes a filter capacitor in the right place will do the job.

The point is, it isn't going to be easy to isolate the cause, just playing around a bit until you find it. Just be careful about what you're doing or you could cause some damage to something or yourself... Most things are protected by fuses or breakers, but unless you know for sure, don't do something you're in doubt about.

Good luck, and keep us posted on how you're doing.

 

[MCF]

Where can I get....

a filter that goes straight into an outlet? It def. sounds like a ground loop buzz, but I know the electrical supply is good as I have gone thru this exercise with a home entertainment system in the same room and tried filters, etc., etc., etc. and it was determined that it was a bad piece of equipment. I am pretty confident that the outlet power and home ground is good. The home is new and my audio/video equipment on the same breaker have no signs of a 'ground loop' - no buzz and no 'wave' on plasma tv. Using the CW-80, is it possible to take the Lockon out of the loop? It is either the engine, the CW-80 or the Lock-on. Don't know if it is worth mentioning, but the CW-80, Lockon and Command Base are all located inside my loop of track all very close to each other...could this cause some problems?

 

[ezdays]

I cannot answer your specific questions regarding the CW-80 since I'm not familiar with it. What I do know though is that something like this requires a lot of "playing around" before you find the culprit. I had a system we installed in a Navy brig that included door controls and an intercom system. Once installed there was this buzz in the speaker when selected. It turned out that I put a connection between the door control and intercom grounds. I removed the jumper and the buzz went away. I also had a similar problem at home with some remote TV speakers. I finally grounded one of the speaker wires and the buz went away. The point is that you're going to have to keep plugging along, move things around, change your grounding system or whatever to see what affect it has.

And no, I'm not suggesting you put filters on the AC input, rather sometimes a filter on the output works. Like if you're running AC on your tracks, a .01 mfd capacitor from each rail to earth ground might work. In this case, larger is not better. If you're running DC to the tracks, a non-polorized capacitor between the rails could be effective at reducing the noise.

 

[kadidle]

If it is 60hz hum, call around for a Tripp Lite Isobar. This is an AC filter that will help with the hum (it's actually a harmonic hum created by flourescent lights, inverters, inappropriate premise grounding, and even microwave ovens/equipment). We had a problem with this when we installed our microwave internet, finally found out that the transmitter was feeding back through the wall wart. The isobars not only cleaned that noise up but also eliminated some issues with our tv picking up noise, which was caused by having 3 grounding rods (a no-no apparently).

 

[MCF]

Before I waste any time or money....

chasing a ground loop (which I have done before in the exact same room and finally discovered the piece of video equipment was damaged), I am going to take the engine and transformer to a local shop and let them run it on their conventional and TMCC setups. I have already talked to Lionel and they said they have had this problem before (not necessarily with the Black Diamond though) and they are sending me a RA number. If the buzz exists at the shop, I am sending the engine in....

Thanks for the input...I may need it if I get the engine back from Lionel and experience the same buzz...