Stay Alive capacitor

[7013]

Hi

I have just purchased a sound chip (Zimo) for my Coronation. It comes with a stay alive capacitor which is fairly straightforward to wire in. However I have noticed some diagrams of stay alive capacitors wired in with Diodes attached. Would I be right in assuming that they are not necessary if the correct capacitor is supplied with the sound chip in the first place? I would be grateful for some guidance.

[Nigelcliffe]

Different decoders have different requirements.    Some Zimo models have charge/discharge circuits for capacitors built in, and connection points added.   Some don't, so you need your own charge/discharge components (typically a diode and a resistor), and also need to know where to make connections.  

 

That the decoder comes with stuff packaged, and I hope instructions, is all you need for that particular model of decoder.   

 

 

If seeking the general case, then a lot of reading of makers manuals, possibly followed by some web searches, will be needed.  

 

 

- Nigel  (long time installer of stay-alives, including into stupidly small locos ). 

[7013]

Thanks Nigel, given that the decoder has two wires attached that are specifically for the stay alive I am assuming that it has the requisite circuitry built in. Thanks for the info though.

[pauliebanger]

Thanks Nigel, given that the decoder has two wires attached that are specifically for the stay alive I am assuming that it has the requisite circuitry built in. Thanks for the info though.

 

You are both correct.

 

From your description, this is a ZIMO MX645®. The decoder includes the required charging circuit to which Nigel alluded and also a regulated 16V supply. Grey wire to negative lead on the capacitor and blue wire to the cap positive.

 

Please bear in mind of what these caps are capable.

 

The supplied caps are sufficient to prevent loss of sound during short power break or during brown-outs but will not transform your model into an off roader like this (also using an MX645R, but with supercaps totalling 16.2v and 166,666uF capacitance): from about 2min 45secs

 

 

Kind regards,

 

Paul