# Lineage of Scroller Power Supplies



## Footer (Apr 28, 2010)

Inspired by this thread, what is the difference between "RAM" power supplies and the more modern "Chroma-Q" power supplies that are now used by all the large manufactures. 

What separates these two styles of power/control? When was "RAM" style introduced? When was the "Chroma-Q" style introduced? How are each pinned out? What style is current Coloram IT using? 

General QOTD rules apply, if consider yourself a professional, hold off answering for one week or until the question is answered!


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## GreyWyvern (May 4, 2010)

Wow, no one has even taken a stab at this yet. I bet Kelite is just itching waiting for tomorrow when he can finally give all the detials.


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## n1ist (May 4, 2010)

From a little bit of hunting:

The main differences are the pinout and addressing schemes. 

- Chroma-Q scrollers are DMX devices, and the power supply acts as a DMX splitter. DMX addresses are set on the scrollers. The Coloram IT uses this style, but the supplys for them supports RDM.

- RAM power supplies *have reverse polarity on the +24V*. The data between the scroller and supply is a differential pair, but appears not to be DMX. A base address is set on the power supply itself, and the scroller has a sub-address within the block of 12/24/48 (depending on version) to get the final DMX address.

- And for another incompatible power supply, the ProCommand (Morpheus) scrollers have the 24V rail on yet a different set of pins.

Pinouts:
Chroma-Q 1: GND, 2: DMX_N, 3: DMX_P, 4: +24V
RAM 1: +24V, 2: DMX_N, 3: DMX_P, 4: GND
Morpheus 1: DMX_N, 2: DMX_P, 3: GND, 4: +24V

So the obvious rule is to make sure your scrollers are compatible with your power supplies or they may smell funny.

/mike


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## Kelite (May 4, 2010)

We have a winner!

For the bonus point, can you tell us: <When was the "Chroma-Q" style introduced?>


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