Polar Express lighting puzzle

Dallas JosephOGR Forum Member SUPPORTING MEMBER

Two years ago I installed an incandescent light in the PE engine cab . It worked OK .

I recently had a good time installing LEDs in everything on the layout and everything that runs on the rails . I installed an LED in the headlight socket and snipped off the incandescent bulb in the cab and used the ends of its wires to solder the LED to.

Everything works fine on my 6' Realtrax test track . On a totally wired 6' Fast track that came with the PE everything works fine......except the LED in the cab doesn't light . I repeated the track change several times with the same result.

I am using the PE remote on both tracks . My test track is powered by a Z1000 and the MTH controller. The PE stock transformer is used on Fast track section.

Can't figure this one out. Social distancing seems to give me time to find all kinds of interesting oddities in the train room.

4/28/204:22 PM

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GregMOGR Forum Member DIGITAL SUBSCRIBER

Just a guess but this may be because the Z1000 output is AC whereas the PE wall wart output is DC. The LED doesn’t see the correct polarity with the PE transformer while the LED sees the correct polarity for one half of the AC cycle with the Z1000. If possible connect the Z1000 to the Fastrack to confirm this is the problem.

4/28/207:00 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Greg has your answer, it's designed to be an AC bulb and they didn't use a bridge rectifier, but just a diode.

4/28/207:18 PM

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Dallas JosephOGR Forum Member SUPPORTING MEMBER

Well guys ,

The headlight still works with the same type of LED . ( I'll have to find the post that I showed a photo of one of these plug in LEDs when I had one apart and show it on this thread . )

I think you have given me the answer though . 🤤

Ill have to take the PE apart and solder the wires on the cab light in reverse.

I didn't think about the AC / DC because I never needed to care about polarity on the DCS . I do remember using your rectifiers for the passenger cars John, and I had to make sure I soldered the the wires correctly for polarity.

I probably soldered the wires correctly by accident for the working headlight LED and not for the cab LED.

I can't wait to get the PE opened up again . Still learning.🤔

Thanks Greg and John.

4/28/2010:02 PM

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Dallas JosephOGR Forum Member SUPPORTING MEMBER

The LEDs in question.