Zimo MX633P22 connecting Capacitor?

[dj_crisp]

Hi

 

I thought I'd try a Zimo MX633P22 decoder and can see it comes with a capacitor for stay alive...

 

 

Question is - where do i fit it?

 

I think the instructions are suggesting soldering to the pins? I was kinda expecting pads but can't see any?

 

Any help is gratefully appreciated

 

thanks

Will

[Ray H]

Looking at the leaflet and comparing it to the decoder I'd suggest that you probably can't solder to the pins or the connector won't fit. Instead you appear to need to solder the wire's to the pads alongside the (respective) pins.

 

Again, from drawing and decoder it looks as though you solder it to the third pad down on either side of the pins as shown on the drawing.

 

You'll need a fairly small bit tip on the iron.

 

Hope that helps.

[Mike Buckner]

If you are installing the decoder into a loco with a pre-existing Plux22 socket provided by the manufacturer, then hopefully, they will have connected the Stay-Alive pins to some convenient points on the circuit board to which you can solder the capacitor leads.

 

If you are installing the decoder into a loco with no pre-existing Plux22 socket, then you could obtain a "breakout board", and solder the capacitor leads, and everything else, to the breakout board. You need to find a breakout board with suitable dimensions to fit inside your model.

 

Some example boards:

 

https://www.ebay.co.uk/itm/224025839775

 

https://www.esu.eu/en/products/accessories/adapterplatinen/plux22-adapter-board-1/

 

https://www.conrad.com/p/tams-elektronik-70-01035-01-interface-adapter-assembly-kit-wo-cable-incl-connector-404211
 

[dj_crisp]

Thanks! I'm planning on installing into a Bachmann class 121 so will have a look to see if there are solder pads

 

Thanks both for your help. I always seem to struggle with DCC

 

Cheers

Will

[Michael Hodgson]

The capacitor is fairly bulky compared to the decoder, and as you might want to stow them in different places in the vehicle, it may well be preferable to connect the two devices toegther with short lentghs of insulated wire, rather than connecting directly to each other.

 

The polarity is important - connect Capacitor (+) terminal of the decoder (the left hand one on the third row) to the longer lead of the capacitor and the negative or shorter lead of the capacitor (should be adjacent to a grey stripe) to the Ground terminal (the one to the right, also third row)

[NIK]

Hi,

 

You may find the link to more info you need about the stay alive capacitor is hidden in the photo under the DCC decoder.

 

Regards

 

Nick

[dj_crisp]

Thanks all for your help

Well I soldered a capacitor in as per the photo.

 

 

So I've either soldered it in the wrong place or it doesn't have much effect.

 

Unit runs very nicely using this decoder though!

 

Cheers

Will

 

[grriff]

Have you turned off the option of running under DC (CV29)? 

[Nigelcliffe]

470uF of capacitor, will result in a run time of maybe 0.1seconds at best, probably less.  You'll do well to spot it, though its making a tiny difference, mostly keeping the decoder from restarting in the event of a pickup glitch.  

 

You need thousands of uF to have a noticeable effect. 

And there are lots of us fitting 100,000uF and above, which should give several seconds of run without power.  

 

 

There are stated limits in the Zimo manuals for capacitors connected in the way illustrated.   
The Zimo manual says : MX633 can accept .... 140,000 μF (7 x 1F gold caps in series) .   
Don't buy super-caps from ebay or electronics sources unless you understand the spec sheets - quite a few designs of super-caps are not suitable for the rapid discharge required in a stay-alive.    

 

 

The alternative connection is to the decoder positive and decoder ground; for that a capacitor also requires a charge/discharge circuit; either as separate components, or integrated into the bought-in stay-alive module.  

 

 

- Nigel

[dj_crisp]

On 01/04/2022 at 18:17, Nigelcliffe said:

470uF of capacitor, will result in a run time of maybe 0.1seconds at best, probably less.  You'll do well to spot it, though its making a tiny difference, mostly keeping the decoder from restarting in the event of a pickup glitch.  

 

You need thousands of uF to have a noticeable effect. 

And there are lots of us fitting 100,000uF and above, which should give several seconds of run without power.  

 

 

There are stated limits in the Zimo manuals for capacitors connected in the way illustrated.   
The Zimo manual says : MX633 can accept .... 140,000 μF (7 x 1F gold caps in series) .   
Don't buy super-caps from ebay or electronics sources unless you understand the spec sheets - quite a few designs of super-caps are not suitable for the rapid discharge required in a stay-alive.    

 

 

The alternative connection is to the decoder positive and decoder ground; for that a capacitor also requires a charge/discharge circuit; either as separate components, or integrated into the bought-in stay-alive module.  

 

 

- Nigel

Thanks Nigel... that makes sense.

 

I think I'll save the expense on my next decoder and not bother with the stay alive option

 

Cheers

Will 

[dj_crisp]

On 01/04/2022 at 17:28, grriff said:

Have you turned off the option of running under DC (CV29)? 

 

I haven't. Does that make a difference?

Thanks

Will

[grriff]

It does make a difference. 

From TrainBoard.com:

The motor may stop running because of the way CV29 is set. In many decoders, you must TURN OFF analog conversion mode (sometimes called "DC operation mode") for the motor to keep running off a keep-alive. The reasons for this are that if the decoder senses there is no dcc signal at the track, it will go into analog conversion mode; but there is also no DC current at the track, so the motor stops - the decoder interprets the lack of DC voltage as a "stop" command in analog conversion mode. To avoid this, you must turn analog conversion mode off. 

This is assuming your capacitor has sufficient charge

[Nigelcliffe]

1 hour ago, grriff said:

It does make a difference. 

From TrainBoard.com:

The motor may stop running because of the way CV29 is set. In many decoders, you must TURN OFF analog conversion mode

 

 

Changing CV29 when fitting stay-alive devices is not necessary in Zimo decoders.  

 

 

 

 

- Nigel

 

 

[dj_crisp]

Thanks both.

I didn't see any difference when I tried it.

 

Cheers

Will