# Capacitor Redux



## Goldie (Dec 27, 2010)

Would anyone happen to know if Gilbert's "Diesel Roar" feature normally transmits the sound produced by the coil/ vibrating reed device through the speaker? I replaced the capacitor and got this result yet a video on Youtube by a mister Brian Reilly demonstrates a difference. What gives?


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## AmFlyer (Mar 16, 2012)

The sound is reproduced by the speaker . Are you certain the the vibrator tube is good? That the control switch is correctly connected to the track?


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## AmFlyer (Mar 16, 2012)

Here are the repair instructions for the Diesel Roar unit if you do not have them.


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## Goldie (Dec 27, 2010)

Sorry, I should have been more clear. The roar feature I'm referring to is housed in a 492 Alco PA.


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## AmFlyer (Mar 16, 2012)

A 492 is a non motorized NP PA. The instructions will be the same.


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## Goldie (Dec 27, 2010)

Thanks so much for the detailed instructions AmFlyer, I really appreciate your effort. May I ask what instruction book this is from?


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## AmFlyer (Mar 16, 2012)

The book is Complete Service Manual for American Flyer Trains by K-Line (MDK, Inc.)
The page I posted is also accessible online. Go to myflyertrains.org, under Categories open Gilbert Paper, then select Factory Service Manual-Online. It is page 168 in the Locomotives section.


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## AmFlyer (Mar 16, 2012)

Goldie, you should also look at the section titled Locomotive Whistles in the Factory Service manual. It has 11 pages of applicable information that covers every possibility.


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## Goldie (Dec 27, 2010)

Tom (AmFlyer) you are too kind and I am in your debt. Thanks so much for your responses and willingness to share your knowledge.


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## AmFlyer (Mar 16, 2012)

I hope it helps you get the diesel horn working. Let us know.
Some other thoughts. A pure sine wave transformer is required, such as original Gilbert or the modern MRC Pure Sine Wave transformer, to operate engines with the horn feature. Other modern power supplies that output a modified shape waveform will cause the horn to sound continuously from the harmonics in the output. The old Gilbert postwar engines and accessories were designed for a maximum of 16V. Be careful with Lionel and some of the modern transformers, some can output as much as 24V.


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## Goldie (Dec 27, 2010)

Well whadaya know?! Tom, you're a saint! I was using a Z-4000 and the speaker was harmonizing with the "roar", which prompted my original question. As per your advice, I tested again with an 8b and the "roar" sang solo! Thanks again and again for your help!!! So glad to find this out now before layout construction as it looks like I'll need two different power sources to run both modern and vintage locomotives. Thanks again for solving this dilemma!

Goldie


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## AmFlyer (Mar 16, 2012)

It does force some tough decisions. I have chosen the ZW-L for my new layout and will live with the fact that I cannot run any original Gilbert engines that have the diesel horn or tender whistle.
It is easy to install both transformers with a DPDT switch to select one or the other. Alternatively one can have a dedicated block or loop for running those engines with the horn.


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