[chiplotle-discuss] making a power supply for a Roland DXY

Rupert Brooks rupert.brooks at gmail.com
Fri Apr 27 07:20:51 EDT 2012


An LM317 would be a good regulator to regulate the 12V down to 9.7V.
Check the power requirements, however. The sample circuit in the
datasheet will almost certainly work, adjusting the variable resistor
to get the right voltage. http://www.ti.com/lit/ds/symlink/lm117.pdf

32v is probably fine, i assume it probably runs the motors so its
likely not too sensitive.  If you need to drop 32v to 31v though, then
a diode in series will drop a constant value, about 0.6v.  Note that
the diode will dissipate 0.6 x current in amperes = power in watts.
Make sure you use one rated for the necessary power, or the magic blue
smoke will escape.

Good luck,
R
--------------------------------------------------------------
Rupert Brooks
rupert.brooks at gmail.com


On Thu, Apr 26, 2012 at 21:33, Douglas Repetto
<douglas at music.columbia.edu> wrote:
> Voltage dividers are not generally a good way to generate needed voltages.
> I'd recommend getting a good regulated supply that is close to the higher
> voltage (32v is probably fine) and then using a variable voltage regulator
> to dial in the other voltage. Make sure to also check the current
> requirements on the original supplies. Your new supplies need to provide at
> least as much current as the originals.
>
> douglas
>
> http://music.columbia.edu/~douglas
>
>
> ----- Reply message -----
> From: "John Honniball" <coredump at gifford.co.uk>
> Date: Thu, Apr 26, 2012 7:10 pm
> Subject: [chiplotle-discuss] making a power supply for a Roland DXY
> To: "chiplotle - now that's a spicy plotter library!"
> <chiplotle-discuss at music.columbia.edu>
>
> Joe Frey wrote:
>> Hello all, I tried to modify a power supply with 2 resistor networks. I
>> got the information here and did the math to drop a 32v/16v DC supply to
>> 31V/9.7V DC.
>>
>> http://www.ehow.com/how_5794977_step-down-dc-voltage-transformer.html
>
> Can you say what value resistors you chose?
>
>> I checked that I was in the neighborhood with my VOM and I was.
>
> Did you check the voltages with the plotter connected and
> switched on, or with the plotter disconnected?
>
> --
> John Honniball
> coredump at gifford.co.uk
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