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Adding capacitors to a DCC decoder (non sound)

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  • Member since
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  • From: Ontario Canada
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Posted by Mark R. on Friday, May 10, 2013 12:11 AM

You won't get any "stay alive" capacity from any single capacitor that will physically fit that little guy.

For a single capacitor, you need at least a 16 volt rating and at least 100,000 microfarads to get a second or two stay alive ability - plus a resistor and diode .... which won't even come close to fitting. The TCS modules have one farad of capacitance (one million microfarads) but use multiple 2.5 volt capacitors in series to get the size down.

Instead of the drive you used, you could have used one of NWSL / Stanton drives and had both hoods and the cab wide open which would have given you plenty of room for a decoder and stay alive module ....

http://www.nwsl.com/uploads/cat_chap2_for_web_3-01-13.pdf

Mark.

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

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  • From: Bradford, Ontario
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Posted by hon30critter on Thursday, May 9, 2013 6:44 PM

I have looked at all the TCS offerings, both for the add-on circuit and for the decoders that have the Keep Alive built in. They are all too large to install in the switcher itself.

I do have a TCS Z2 decoder on order which is supposed to be pretty small. It is intended for another project but when I get it I will see if using one in the 15 tonner will give me any more space. The TCS Z2 does not have the Keep Alive function. I am using a Digitrax DN135 right now.

I have the option of removing some of the weights to make space but that seems to be totally counter productive. Even then, there is only 7/16" from the front to the back of the cab. All of the TCS circuits are larger than that. Even if I put them on their sides they still won't fit.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by wjstix on Thursday, May 9, 2013 4:51 PM

TCS offers decoders with the "keep alive" built in. They're the same size as a regular HO non-sound decoder. The "keep alive" add-on only works with TCS decoders that have a place to plug-in the add-on.

If you can find the room, go for the TCS. I had a first-run Proto 0-8-0 that came with no power pickup from the tender wheels, and it ran so poorly I never used it. I put a TCS "keep alive" in it, and now it runs great.

Stix
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  • From: Western, MA
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Posted by richg1998 on Thursday, May 9, 2013 2:21 PM

Check the dimensions of the stay alive decoder at the TCS website. Most online DCC stores show the specs also.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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  • From: Chi-Town
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Posted by zstripe on Thursday, May 9, 2013 1:48 PM

CACOLE,

Do you think they will fit in that mouse,he has though??

Cheers,

Frank

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
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Posted by cacole on Thursday, May 9, 2013 8:46 AM

Look at the Train Control Systems web site -- they have a "keep alive" module that can be added to an existing decoder. 

http://www.tcsdcc.com/

  • Member since
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  • From: Chi-Town
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Posted by zstripe on Thursday, May 9, 2013 4:37 AM

Dave,

Who knows,the way,the Electronic's Software industry is growing,these day's,,they may come up with a NANO,circuit,that will provide,what you need...

Talk To You,,

Cheers,

Frank

  • Member since
    July 2006
  • From: Bradford, Ontario
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Posted by hon30critter on Thursday, May 9, 2013 2:20 AM

Hi Frank:

Ya, I am beginning to realize that this may not be possible without a trailer as you suggested.

However, I ain't quitting just yet! Just have to put my thinking cap on, that is if I can find it!LaughLaugh

Thanks a bunch for your help. Edit: see my post about banging my head above!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    January 2010
  • From: Chi-Town
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Posted by zstripe on Thursday, May 9, 2013 1:56 AM

Dave,

I forgot to mention,,being the room,you have available in that little mouse,,,that is going to be the tough one...

Cheers,

Frank

  • Member since
    July 2006
  • From: Bradford, Ontario
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Posted by hon30critter on Thursday, May 9, 2013 1:53 AM

Thanks Frank

I checked out the Lion's post and came to the conclusion that the solution to my problem may not come easily, if at all.

That however, is not going to stop me from investigating further. Good thing my back surgeon said I had really solid bones! I can afford to bang my head that much harder!!Laugh

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    January 2010
  • From: Chi-Town
  • 7,712 posts
Posted by zstripe on Thursday, May 9, 2013 1:44 AM

Dave,

You would need a Polarity sensitive,Electrolytic,capacitor,and other components,to do what you are asking and I am rusty on that.. Check out ,Elect.and DCC,Forum,on Rad Lite LED Lites for passenger cars and read the Lion's, post...That should help you....

Cheers,

Frank

  • Member since
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  • From: Bradford, Ontario
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Posted by hon30critter on Thursday, May 9, 2013 1:19 AM

Hi Frank:

I have some SMD 0603 capacitors that are rated at 100pf. My problem is that I don't understand capacitor ratings so 100pf does't mean much, but I am assuming that they are pretty small. I am wondering if it would be possible to wire a number of these small capacitors into a larger 'block' (for lack of a better word), and get anything useful out of them? How much 'capacitance'( is that the right word? ) would I need to bridge momentary interuptions in power for a non sound motor?

I know that TCS has a capacitor power interuption device available but there is no way that it will fit in the 15 tonner, and I am trying to avoid using a 'trailer' as you suggested. I also don't think I need several seconds of alternative power supply. One second would seem to be more than adequate given the current performance of the engine as long as the recharge time is fairly quick.

By the way, if anyone could enlighten me on capacitor ratings and relative functionality, that would be very much appreciated! I used to love running my boat in the dark, but that was when I knew where I was going and I could see the horizon!Smile, Wink & GrinLaugh.

Dave

EDIT: It didn't take me too long to figure out that the 100pf capacitors would be rather useless in this installation once I read the posts.

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    January 2010
  • From: Chi-Town
  • 7,712 posts
Posted by zstripe on Thursday, May 9, 2013 12:42 AM

Dave,

Anything that I'm aware of,you would have to have a trailer,to put it in,,,,hopefully there is,some circuit,that is small enough to fit,,,,that's little!!!

Have fun!!!!

Cheers,

Frank

  • Member since
    July 2006
  • From: Bradford, Ontario
  • 15,797 posts
Adding capacitors to a DCC decoder (non sound)
Posted by hon30critter on Thursday, May 9, 2013 12:25 AM

Hi everyone!

I am working on a Mack 15 ton switcher engine kit. The body is from Jordan and I am using a powered truck from an older Bachmann 44 tonner as motive power as per Darth Santa Fe's original idea.

I have the power truck running OK but it is very sensitive to power interuptions. Yes, the track is very clean. The body has a fair bit of added weight in the form of lead sheet. Test runs without the body revealed frequent stalling. Test runs with the body in place reduced the tendancy to stall but did not eliminate the problem completely.

My question is about installing capacitors to keep the motor alive during the brief power interuptions. I would like to know what size would be effective, and I would like to know exactly where in the circuit to install them. There is no sound (I wish there could be but there simply isn't space for a speaker.) Space is at a premium but I have about 1/2" x 3/8" x 1/4" still available in the upper part of the cab.

Here is a picture with the body off. If you look into the lower sides of the cab you can see where the lead weight has been installed:

Here is a picture with the body loosley installed. Sorry about the focus. You can see that there isn't a whole lot of space for big capacitors. The wires sticking out the top are for the headlight/tail lights.

Any suggestions about capacitors?

Thanks as always.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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