4-6-0 Tweetsie New Chassis - Now No Tender Sounds

[rfarmer]

I have a Tweetsie 4-6-0 Big Hauler that I just installed a new chassis on. Everything works fine with the exception of the tender sounds. With the old chassis they work fine. With the new chassis I only get the "chuff" when I push the switch on the back of the locomotive down. Push switch down – chuff. Switch up – quiet. Down – chuff. I placed the old chassis on the track and reconnected the tender to make certain nothing had happened to the tender and it works as expected. Since I get the "chuff" when moving the button but not when the engine is in operation on the new chassis - Just wondering – could the polarity coming from the chassis to the tender possibly be reversed? There can't be much wrong. The chassis is brand new. The tender works great with the old chassis. I'm just looking for some input and hoping perhaps you guys have seen this before. Thanks in advance!!

[Loco Bill Canelos]

HO Farmer,

There is no power from the loco to the tender, so I don't think it is a polarity problem.  All the power comes from the 9Volt battery in the tender itself.  The red button on the back of the loco must be down and stay down.  The wires from the loco to the tender are simply the chuff  Be sure the plug between the loco and tender Has "sound" printed on it usually in red.  Be sure the correct plug is used.  Also I am wondering if the chassis you bought is the Annie chassis or the Big Hauler chassis?? 

You probably did all of the above, so check out this link:

https://www.bachmanntrains.com/home-usa/board/index.php/topic,30394.msg224039.html#msg224039

Scroll down to the middle of the page and find the sound trouble shooting guide.  Since the sound works fine with the old chassis the problem is most likely the chuff sensor or a problem with the red switch.  Expose the chuff sensor, be sure the two copper arms are in contact with the drum.  If they are and you have a voltmeter, set it to the continuity  mark which is the Omega symbol on the dial.  If the copper arms are not touching one of the silver bars on the sensor drum, you will get a zero reading.  If the copper arms are touching one of the silver bars on the drum, then the reading should be one.  This would indicate all is good with the chuff sensor.  If still no sound the only other thing I can think of is the red switch is not making good contact in the down(on position)

Hope some of this will help, if not get back to us, and we will keep trying.

Loco Bill

[Joe Zullo]

HO Farmer,
Since the sound works fine with the old chassis the problem is most likely the chuff sensor or a problem with the red switch.  Expose the chuff sensor, be sure the two copper arms are in contact with the drum.  If they are and you have a voltmeter, set it to the continuity  mark which is the Omega symbol on the dial.  If the copper arms are not touching one of the silver bars on the sensor drum, you will get a zero reading.  If the copper arms are touching one of the silver bars on the drum, then the reading should be one.  This would indicate all is good with the chuff sensor.  If still no sound the only other thing I can think of is the red switch is not making good contact in the down(on position)

Loco Bill

You have the meter reading backwards, sort of.
If both chuff reeds are not touching a bar on the drum your ohm meter will read infinity (open circuit) not zero. If they are both touching a bar then your meter should read close to zero ohms (your meter leads will be in the resistance measurement).

[Loco Bill Canelos]

Thanks Joe,

Appreciate the correction!

Bill