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Location: Snowy WIsconsin
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A couple question about Placid BP (v2.1.2):
1 - schematic says VR1 and VR2 are 200ohm. Parts list and parts number on Mouser say 20ohm. Which is correct?
2 - I'm having problem with one side of the supply (Out1 side). I can adjust the voltage with VR3 just fine but the current adjustment VR1 has no effect. Also, as soon as I connect a load the voltage drops and no longer adjusts. The heatsinks on QN1 and QP3 are warm but no where near as hot as on the other side. Is one or both of these blown?
Thanks in advance for your help.
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1. 20R is correct.
2. Sounds like transistors is in the wrong spots. Double and triple check these. Many times I have verified them to be in the correct position, only to recheck later and find them in the wrong spots.
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Rank: Member
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Location: Snowy WIsconsin
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Thanks for the quick response Brian. The transistors are correct. The Placid BP has been up and running for over 6 months now. Only been having problems since I tried swapping Legato for IVY. Is it possible I fried QN1 while adjusting the current draw?
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You have prob. blown VR1. Replace, and your'e back in business.
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Yes 200R VR1 is not for heavy loads. 20 or even 10R is better if your going to be running it hard.
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Rank: Member
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Joined: 1/1/2010(UTC)
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Location: Snowy WIsconsin
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Yup. That was it. Strangely that VR1 was new just installed so must have been bad. Luckily I'm in the habit of ordering extras of everything so am up and running again.
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