Author Topic: Leave out transformer?  (Read 2870 times)

Offline soakes94

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Leave out transformer?
« on: May 19, 2011, »

Offline n1ist

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Re: Leave out transformer?
« Reply #1 on: May 20, 2011, »
To feed it from a DC source, leave off the input connector,  fuse, transformer, bridge, and 680uF cap.
 
If you have a regulated 5V source, also leave off regulator.  Feed 5V to the regulator pin closest to the fuse, and ground to the middle pin of the regulator.

If you have a regulated or  unregulated DC source between 7 and 15V, feed it to the two terminals of the bridge rectifier labeled + and -.  You may want to add a 100nF or 330nF cap in place of the 680uF one to reduce the chance of the regulator oscillating.

/mike

Offline lightingnut

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Re: Leave out transformer?
« Reply #2 on: August 12, 2014, »
Hello Mike,
I wanted to check to see if leaving the transformer off the splitter is still the same. I want to power 2 boards with 5v DC and run the power down the same cat5 wire that the DMX will be running in, (not the same pair of wires as the DMX but the same cable). I wonder if the distance from power supply to first board is to far. It will be about 65 feet to first splitter then another 10 feet to the next. Will this be to far for 5 volts to run and not lose too much voltage. What size power supply in regards to amps should I buy?

Offline dmaccole

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Re: Leave out transformer?
« Reply #3 on: August 12, 2014, »
I think if I were doing this, I'd us 12 volts to feed the splitters over that far of a distance. Bring the feed into the mounting points that would be the output of the transformer and leave the 7805 and associated caps in place. That way whatever line drop you got over the 65 feet would still be enough to make the 7805 work properly.

\dmc
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Offline lightingnut

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Re: Leave out transformer?
« Reply #4 on: August 13, 2014, »
What about leaving the fuse and wire connector on the board then run 12 volt DC to the wire connector then on the transformer mounting holes place 2 jumpers to get the 12v DC to the output side of where the transformer would have been mounted. Your thought.

Offline dmaccole

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Re: Leave out transformer?
« Reply #5 on: August 13, 2014, »
Sure, that would be a clean way to do it.

\dmc
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Offline Jeffl

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Re: Leave out transformer?
« Reply #6 on: December 06, 2014, »
I ordered splitter PCB's and they came as V2, the older style and the BOM was V3 which has a new transformer.  Beings I had everything built before I installed the transformer I figured I had nothing to loose by trying to get the transformer to work.  I used the schematic off the Pixelnet splitter and noticed it used the same components as this version except for the transformer.

Now I wouldn't advise just anyone to do this because it's AC power you are working with but it does work (speaking from a non electrical engineer perspective).  Obviously a walwart might be better or safer, you tell me.  I just drilled 6 holes through the PCB for the new transformer and ran new traces on the back side.







Offline RJ

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Re: Leave out transformer?
« Reply #7 on: December 07, 2014, »
I pm you but I see you already got it to work. I have some old pcbs left and grab the wrong ones for you order. I am sorry about that.

RJ
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Offline Jeffl

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Re: Leave out transformer?
« Reply #8 on: December 07, 2014, »
No problem.  It was an educational opportunity.