Berkshire TMCC Issue

Gene-

Can you post the model # of the Berkshire? The chuff control has varied over the years, ranging from a mechanical (cherry) switch to reed switches. At first glance it sounds like a possible wiring or switch issue; does the problem occur with the tender off?

-John

It is model #6-38050. If I lower the volume it sounds normal but if i raise the volume it chuffs real fast. If I start up on high volume it chuffs fast at idle.  If I swith to signal sounds the sounds off except whistle and bell.

Gene-

Thanks. From what I see in the exploded parts view (link for engine; link for tender), the chuff switch is inside the engine (see part #18 on the engine parts list). My guess is part of the drivetrain presses on this switch to send the "chuff" signal, probably one of the drivers. Since the speakers are in the tender the switch must be sending signals to the tender in order to make the "chuff" sound, so I would test the switch, the switch harness, the IR receiver/transmitter (as there is no drawbar) and the tender harnesses for any evidence of damage. Replacement parts are available, but anything more might warrant a trip to the service technician.

-John

Gene-

Just found the wiring diagram online here, which should help with troubleshooting.

-John

Your descriptions are a bit confusing, would it be possible to post a video of the problem?

Is it fast chuffing or just static? The volume knob in thetender can go bad creating excess static.

Theres no such thing as a "fast idle chuff" in o guage or on the prototype for that matter, no chuffing unless the locomotive is moving.

The chuffs on that loco are triggered by a cam on one of the locomotive axles,you get 2 chuffs per driver revolution.

The cam triggers the  cherry switch John mentioned.

Usually when the chuff/cherry switch goes bad you have no chuff at all when the locomotive is underway.

I've never heard of high speed chuffing related to volume positon especially since the loco and tender are not connected electronically.

If the cherry switch was the issue it would be causing it at any volume, It merely sends out the chuff "signal' it doesn't "know" what the volume position is.

I'd say the issue may lie in the tender, possibly the volume knob.

As a test place the tender on the layout by itself and power it up. It will startup and have idle sounds. Try adjusting the volume knob and see if it still reacts the same as when its behind the loco.

I agree with RickO, it has to be some sort of static in the volume pot. A video would help out a lot to figure this out

Alex

When it is chuffing fast are all the chuffs the same volume or is one loud and others softer? Seems to me if it was the volume knob there would be static even with Signal Sounds. I would be looking at the cherry switch. They are usually a PITA to get to but if you can see the two wires coming off the switch put an ohmmeter across those wires and move the drivers by rotating the flywheel. The reading should jump between zero or close to it and infinity or many 1000s of ohms. If it stays at either of those readings for a complete rotation of the drivers it needs to be adjusted by loosening the mounting screws.

Pete 

You can cycle the volume pot, and possibly use contact cleaner.  It should measure from 0 to 10K (center tap to one outside post) as the pot is turned.  Same for center and other outside post.  Basically one is a 0 and the other is at 10K ohms when the switch is fully turned.

This is really a weird symptom of the pot, unless it is some sort of short and both outside post are getting grounded to the center post.   G

Admittedly grasping at straws but it wouldn't hurt to reset the feature code. If your engine has a wireless tether it should Aux1 74 otherwise its Aux1 4. This is done in program mode after hitting Eng xx (ID#) Set.

Pete

Pete,

   That's the first thing to do. Next is to swap tenders  to isolate whether its engine or tender. 

Bill

I turned the volume control up and down several times and the sounds seems ok now and GGG thank you for suggesting volume control cleaner. I do have a can somewhere but it looks like I'll have to buy another and will probably find it after I buy one lol. Thank you all for your help. Gene 

Glad it was simple.  I do believe those pots have been issues with some Lionel engines.  G