Tender with TMCC--Railsounds acting up

[skregal]

Hi guys,

I pulled out the Christmas set and placed it under the tree but the sounds are really acting up. It is a Lionel Southern Pacific (forgot model number, but not a cheapy) about 5 years old.  It is hooked up with TMCC, CAB and Command Base.  (yeah, overkill for a Christmas train).    Anyway the Railsounds worked fine for a few days this year and then they started going off by themselves without any commands from the CAB.  And they are BLARING LOUD and sometimes the tower will talk, or the brake will screech, or the bell will ring, but they will overlap each other and do it randomly.   The battery in the tender is new.   I tried to adjust the volume on the tender but it had no effect.   The funny thing is the Railsounds on/off switch on the bottom of the tender doesn't have any effect either, like it doesn't work, or is disconnected.   The sounds are so annoying that I wanted to turn them off but they won't.   I also tried running the engine with just the transformer and the bell and whistle will still act up, so I thought it must be the tender.   Sometimes it will work OK for a minute, but most of the time the Railsounds have a mind of their own.    Any ideas of what to look for?    I opened up the tender but it all LOOKS fine on the inside????   It is running on Fastrac BTW.

[dougdagrump]

Don't know if it will help any but open the tender and make sure all of the boards are are properly seated in the motherboard and try turning the dashpot, volume control, fully up and down several times. Sometimes the dashpot will get some dirt or corrosion that will cause sound problems.

[ben10ben]

Does it have a wired tether? If it does, the tether may have gone bad, and isn't allowing the sounds to work.

If this is the problem, it should be a relatively straightforward replacement, although you may need to pay a few bucks for a new one from Lionel. 

I've also had really strange problems such as erratic sounds, like you've described, happen with a bad speaker. I'm not sure why it would have caused it, but after replacing everything else(this was a K-line engine, and had the tech stumped as well), a new speaker fixed it just fine.

Those would be my two guesses. 

[lionelsoni]

Whatever you do, don't turn the dashpot!  Turn the potentiometer instead...;-)

http://en.wikipedia.org/wiki/Dashpot

http://en.wikipedia.org/wiki/Potentiometer

[chuck]

If it doesn't have a tether, it may have the IR transmitter/receiver pair between loco and tender.  If these are mis aligned, the unit might be getting interference from random light sources.  Dirty track/wheels/pickups can also generate elcetrical noise that can confuse TMCC and may even even trigger the conventional horn/whistle detectors.   You may need go inside and check the boards in the tender to make sure they are seated properly.

[skregal]

It has a tether which appears in good shape but who knows.   I have turned the potentiometer back and forth a few times but it had no affect.   I will clean the wheels and contacts, the track has already been cleaned when I set it up.   I took apart the tender but I was afraid to take the circuit boards apart because the whole cluster seemed quite fragile to me.