Adding Caps/Keep Alive to Zimo MX621 Decoder?

[tehachapifan]

Has anyone done this? If so, where did you attach to the decoder?

[peteski]

Looking at the drawing in Zimo small decoder manual there are ground and positive (blue) voltage pads on the decoder.  The cap can be wired up to those.  That manual also has some examples of keep-alive circuits where depending on the capacitance value you should add components which will limit the charging current.  Circuit specifically for MX621 is on page 60.  ZIMO decoder manuals are IMO more detailed and informative than ESU manuals when it comes to hardware.

[Steveruger45]

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Here you go

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[tehachapifan]

Thanks, guys!

I had gone to the online Zimo manual and got to a different page that wasn't as clear.

[peteski]

You're welcome.
What manual were you looking at? There should only be one small decoder manual.  Looks like the one Steve and I referred to appears to be slightly older revision.

The latest English Small Decoder Manual is at http://www.zimo.at/web2010/documents/MX-small-decoders_EN.pdf .  I just downloaded it and the same info is now on page 61.

[tehachapifan]

You're welcome.
What manual were you looking at? There should only be one small decoder manual.  Looks like the one Steve and I referred to appears to be slightly older revision.

The latest English Small Decoder Manual is at http://www.zimo.at/web2010/documents/MX-small-decoders_EN.pdf .  I just downloaded it and the same info is now on page 61.

I think I found the same one but didn't dig deep enough, I guess. Early on in the manual, where it has diagrams of a bunch of decoders, it shows how to hook one up to a different model decoder but not on the MX621. Figured that was probably all there was on the subject.