Lionel's Thomas "Diesel"...Service/Horn Operation Questions

dkdkrdOGR Forum Member

Have a NIB 6-28883 version of Thomas's "Diesel". The horn does not work. (Yes, the switch is 'on')

Trying to get the chassis free from the shell to see if the problem is obvious. No info to help in the owner's manual. Removed 6 screws so far. Not budging.

Any suggestions/help/clues/re-direct?

Thanks for consideration.

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UPDATE!!! Second part to the question...

So, at the wife's suggestion I tried checking the horn operation with a different power supply...and the horn responded!!! ( blush )

I have been using an older MRC Dual Power O27 (80VA) supply at the workbench...with which the horn did not respond...a first among all engines I've been servicing, all brands!

I then tried 'Diesel' on the layout...which is powered with an MRC Pure Power Dual (270VA)...and the horn worked just fine!

How come??

11/15/229:14 AM

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Chuck SartorOGR Forum Member

You didn't say which transformer you were using on your layout. The newer electronic horns don't like postwar style transformers. Using an electronic transformer is the answer to get consistent operation.

11/15/2211:34 AM

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Vernon BarryOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

@dkdkrd posted:
Have a NIB 6-28883 version of Thomas's "Diesel". The horn does not work. (Yes, the switch is 'on') UPDATE!!! Second part to the question...
I have been using an older MRC Dual Power O27 (80VA) supply at the workbench...with which the horn did not respond...a first among all engines I've been servicing, all brands!
I then tried 'Diesel' on the layout...which is powered with an MRC Pure Power Dual (270VA)...and the horn worked just fine!
How come??

Easy enough answer, I've seen where the MRC Dual Power 027 has the typical hot of the 2 channels wired common. As such people might wire them backwards to the track, resulting in reverse DC offset polarity-

In layman's terms-

bell button = whistle DC offset

and

Whistle/Horn button = Bell DC offset.

Meaning, ensure you try BOTH buttons because the engine only responds to one, and you may have reversed wiring to the track and thus that reverses the bell and whistle button functions.

11/15/2212:24 PM

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dkdkrdOGR Forum Member

Aw geez, Vernon, Chuck... I'm an idiot! rolleyes Re the polarity thing for electronic whistle/horn...been there, experienced that.

But, the MRC DualPower O27 on the bench has only a whistle button...no bell button. (The other button is for direction change).

Thanks for the gentle reminder. blush

11/15/2212:56 PM

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Vernon BarryOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

@dkdkrd posted:
Aw geez, Vernon, Chuck... I'm an idiot! Re the polarity thing for electronic whistle/horn...been there, experienced that.
But, the MRC DualPower O27 on the bench has only a whistle button...no bell button. (The other button is for direction change).
Thanks for the gentle reminder.
KD

Are we talking about an AH101?

MRC Dual Power 027 with walkaround throttles | O Gauge Railroading On Line Forum

https://www.modelrectifier.com...rces/dc-ac/AH101.pdf

Again, the catch22, some might call this reversed common because again technically the "hot" leads are common for the outputs. This means on a track, where we typically use outside rail as common, and then center rail hot, suddenly we have a problem. So people reverse the wiring (not unlike an early CW80) and that in turn, reverses the bell and whistle button functions compared to the actual DC offset polarity to the track.