# capacitive discharge units



## michael cuneo (Sep 5, 2013)

Hi all, Doe's anybody know who sells kits to make one of these? It doesnt look hard at all thanks Mike


----------



## markgrecco (May 27, 2013)

I had a hard time finding them too. I ended up finding kits, with the parts and PCB, from a guy in Australia. The site is www.talkingelectronics.com. The online purchasing didn't work though and I had to submit the order by email. I bought 2 and they were $10.60 each (AUD) and shipping was $6.50 (AUD) to Canada. Got to love how I can how I can get something from Australia for 6.50 when it would have cost 15 to 20 to get the same thing from the US 

The part was listed on the online store as Capacitor Discharge Unit MkII K-CDU2
I'd send a link but I think he remove the store portion from the site because it wasn't working. To get them you will have to email Colin Mitchell: [email protected] directly and pay through paypal. I've only ordered the one time but he did deliver. I also haven't assembled mine yet to see how well they work but all the parts are there and it's all new stuff.

Mark


----------



## Hutch (Dec 19, 2012)

The MERG site has many many kits. You need to become a member to purchase them and I have found it to be worth the cost. I have a complete DCC system built on their kits and plan on adding more. Here's an example.


----------



## DonR (Oct 18, 2012)

My printer's scanning function is currently inoperative or I would
post a do it yourself Capacitor Discharge Circuit that is easy and
economical to build. Mine has enuf power to throw 5 Peco twin coil
turnouts in one push of the button.

This circuit can be found in Kalmbach's publication "Model Railroad
Electronics" on page 51. If any of you guys have this
very helpful book would you post the circuits. There are 2. One is
extremely simple, using only one diode, 1 resistor and one capacitor.
The other is only slightly more complicated in that it uses 2 diodes and
a simple transistor but offers faster recharge time.

Don


----------



## michael cuneo (Sep 5, 2013)

Hi all thanks for all the quick replys. I have most of the parts asimple diagram would be really nice.I have been looking on line and I saw the MkII on line it requires a darlington transistor BD679which no one has. I like the simple circuit one I hope I can find it. Someone said keep it simple stupid. once again thanks for your help. Mike


----------



## markgrecco (May 27, 2013)

The transistor offers protection to your turnout motor though. I wouldn't count it out because there is a simpler design. It's not a frivolous part of the circuit. Also I agree with building it yourself in some situations but for $10 you'll have all the parts and the printed circuit board to solder everything too. When you think about it you're going to spend about $8 or &9 per turnout motor (I have 40) what's another $10 to help protect them.

I'm not trying to talk you into anything I'm just putting my opinion out there.


----------



## michael cuneo (Sep 5, 2013)

Hi mark I just want to build something simple but effective I'm not rich home all the time just keeping busy Mike


----------



## DonR (Oct 18, 2012)

Use Google: Capacitor Discharge Circuit 

The very first listing that appears has the
simple as well as transistor controlled circuits.

There are a number of other listings also.

Don


----------



## michael cuneo (Sep 5, 2013)

Hi don I went to google images and found the diagrams I need . again thanks every one Mike


----------



## Adam (Feb 13, 2015)

*Scaletrax switch burned up even with capacitive discharge.*

Anyone ever have a switch machine burn up even with a capacitive discharge unit in the circuit? I ask, because I just did and I am thouroughly confused. I thought the cdu "idiot proofed" the switch machine to PREVENT burning it up. If anyone has any insight as to how this could happen, please enlighten me. I am going through these switch machines at a pretty steady pace and it is getting expensive.


----------



## DonR (Oct 18, 2012)

Adam

What source voltage are you driving the CDU with?
What is the pulse length of your CDU output? If too
long that would damage the twin coils the same as
pushing a button too long.

I use an ordinary home door bell transformer for my CDU.
It provides 18 v AC and I have no problems with my
Peco PL10 twin coil units.

Don


----------



## Bwells (Mar 30, 2014)




----------

