# CDU with atlas switches using #57 lited controller?



## idivein (Mar 13, 2013)

hi
I have atlas electric switch machines with #57 led lited controller. I want to use a cap. discharge unit to protect machines. i hooked up a CDU but either the lights or the points worked depending on + or - connections to #57. #57 package suggested using #6924 non-derail circuit board as a CDU and still have lights work. I am using a separate 16v AC transformer to power switch machines thru #57. the track is powered with mrc DCC. will one #6924 connected to ac tramsformer work on multiple switch machines? if so how many for each #6924? I only want to use CDU part of #6924 not auto throw. any ideas? any cheap and simple circuits? or wiring?


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## DonR (Oct 18, 2012)

I have a Cap discharge Unit that feeds all of my turnout
panel buttons. I don't use the Atlas #57. Did you wire
the CDU as the input, to the #57 or in the output lead to
the turnout or can that even be done?

Is there more than one input to the #57?

Don


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## idivein (Mar 13, 2013)

wired cdu as input to #57. if i use cdu as output i would need 1 for every switch.i don't know if that would work.there is one input to #57. could i run 2 inputs to same input on 57?
one 20vac and another pair dc 12v?


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## DonR (Oct 18, 2012)

No, you don't want to feed both DC and AC to your #57
input terminals.

Are you now using the power pack accessory AC for your
turnout power?

I don't know the #57. However, seeing pics of it
on line I'm guessing that you throw a lever for
Straight or Diverting, then push a button. Is
that correct? Does the light change when you
throw the lever and before you push the button?

If so, it is doing what I do with a separate DPDT
switch and push button. The DPDT switch does 2
things, it determines Straight or Diversion turnout
throw, and switches LED panel lights indicating how
the turnout is set. Then, I push a panel button to
feed the CDU pulse to the turnout motor.

Don


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## idivein (Mar 13, 2013)

lionel pack 20v ac. can reduce voltage with throttle. 
that is correct. same as you do with 2 switches.


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## DonR (Oct 18, 2012)

idivein said:


> lionel pack 20v ac. can reduce voltage with throttle.
> that is correct. same as you do with 2 switches.


I should have asked before I joined in the thread.

What gauge are you running? I'm beginning to think
3 rail 0 or 027 gauge. 

Are these Atlas 3 rail turnouts?

Don


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## idivein (Mar 13, 2013)

HO. atlas switches using 20v ac to power separate.


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## DonR (Oct 18, 2012)

Unless you can get into these #57's to change the light wiring
you'll either have to do without the light or the CDU. Those
Atlas turnout solenoids go up in smoke with the least little
extra push time on a button. So the CDU gets preference
in my opinion.

Here's an alternative:
You can get very inexpensive DPDT switches and momentary
normally off push buttons and red/green LEDs at Radio shack. One side
of the switch controls which way the turnout throws. The other
side switches LED from Red to Green. You then push the button,
the CDU pulse operates the Atlas solenoid and the turnout throws.
The LED stays on as set. You could power the LEDs with the existing
accessory power, with a bridge rectifier (4 diodes) and install a 470 ohm or so
resistor to match voltage to the LEDs need for appx 2 vdc. You would
need only the one CDU which would operate as many turnouts as you have.

Don


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