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lwr  
#1 Posted : Thursday, November 17, 2011 1:03:13 PM(UTC)
lwr

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I built the Placid HD BP with the supplied 100k R7A and R7B and and it worked perfectly. I needed 15V bipolar out, so I changed R7A and R7B to 750R. Now there is plenty of voltage and current adjustment available, but LEDs RD2A and RD2B do not light. The voltage into each of them is 1.5V, but the voltage into RD1A and RD1B, and into BD1A and BD1B is 1.9V. What is going on here?
Brian Donegan  
#2 Posted : Thursday, November 17, 2011 1:30:33 PM(UTC)
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You do not need to change R7 to get 15V output. It will do that with the default values.
lwr  
#3 Posted : Thursday, November 17, 2011 6:00:00 PM(UTC)
lwr

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The table under Some Helpful Setup Tips on page 2 of the User Manual is where I got the 750R value for R7. The 100K resistors have already gone out with the trash pickup. I am using the Placid HD BP as the supply for a Legato 3.1 that has had R1 - R4 changed to 180R for 2V output with the B2. What do you suggest to get the RD1A and RD1B within the 1.9V operating range?
lwr  
#4 Posted : Friday, November 18, 2011 10:26:19 AM(UTC)
lwr

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Brian Donegan wrote:
You do not need to change R7 to get 15V output. It will do that with the default values.


Will the R7 default value provide enough voltage and current adjustment for a Legato 3.1 that has had R1 - R4 changed to 180R for 2V output with the B2?
Russ White  
#5 Posted : Friday, November 18, 2011 4:18:36 PM(UTC)
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Thanks for pointing that out. It was a cut and paste error in the manual. We will correct that.

R7 should remain 100K.

What the manual is referring to there is picking RG for setting a fixed voltage, and to do that you would omit VR2 and replace it with a resistor. That is what would be 750R.
lwr  
#6 Posted : Friday, November 18, 2011 9:45:00 PM(UTC)
lwr

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Applause Got it. Thanks.
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