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One of the items on my to-do list was to convert my train-show acquired Dispatch station from batteries to delightfully cheap Chinese electronics, especially since my grandson requested it … a few times! And the batteries had corroded into a horrible mess years ago. Here's a quick video to give you an idea of what was involved. 

I wanted to design a circuit such that the Dispatch station no longer relied on battery power, but rather got its juice from the transformer. It works, but my electronics design skills are somewhat lacking, so I suspect with an improved interface, I could get even better sound. If anybody can offer up a schematic that interfaces a telephone-style carbon mic to a standard high impedance amp input, please pass it on!

I also wanted better lighting than the incredibly anemic single bulb - and if you turn up the juice, you definitely risk a station roof meltdown

IMG_1121Top view

The speaker is original, pretty much everything else is new

 

IMG_1123

I love that the original paper scene in the front window was intact - the LEDs do it justice, I think.

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Last edited by GeoPeg
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Hate to post on such an old thread, but I saw this and could not resist doing the same thing. Thank you for including the video link.

I used an LM2596HV based 'AC/DC to DC Step Down Buck Converter AC 5-30V DC 5-48V' ($9 for 2 on Amazon) to run the LED strip and amp from 14 VAC accessory power - this converter looks different from yours and works fine. The amp is a TDA2030A Audio Amplifier Module Power Amplifier Board AMP 6-12V 15W Mono ($8 for 2 on Amazon) which looks exactly like yours. I got the 12v LED strip ($13 for 16') with angle connectors (2Pin 8mm LED Connector Kit $14 on Amazon) to run across the lid. Unfortunately, the original carbon microphone was useless. I purchased a Cobra 4-pin CB microphone jack ($6 on Amazon) and a Cobra HG M75 CB Microphone ($15.99 on amazon) which is powered by a 9v battery and has a 'volume' adjustment knob (perhaps gain is a better word here). I wired pins 1 and 2 from the CB microphone into the amplifier.

All of the items were purchased via ebay or amazon - both sites sell all necessary components. For the modules, search for the model number of the chip, though most of the buck converters using the chip are DC input only, so include 'AC/DC' in your search terms.

As listed above, it adds up to $66 in parts via Amazon. However you can find the electronics in single units cheaper on ebay (shipped from China) which was what I did. I already had the LED strip and suitable connectors from previous projects. My total was $34 for the conversion - $22 of that for the mic and socket. I'd say the LED strip connectors are not necessary and even a bit of a pain to use and should have soldered jumper wires to the pads to go around the corners - pay close attention to the polarity or lights will appear not to work.

It looks and works great!

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