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sbelyo  
#1 Posted : Friday, May 9, 2014 2:42:58 AM(UTC)
sbelyo

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After assembling a placid 2.01 VR2 won't adjust voltage past 3.99 Vdc. Transformer is 9 Vac VR1 adjusted curruent to 350 mA.

I can adjust voltage down, just not up past 3.99, what should I check. I suspect I may have a cold solder joint at VR2, would that do it?
avr300  
#2 Posted : Friday, May 9, 2014 7:12:59 PM(UTC)
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Pictures please, top and bottom.
Brian Donegan  
#3 Posted : Friday, May 9, 2014 7:44:33 PM(UTC)
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Top reasons for this:


  • Misplaced transistor. Double-, then Triple-check the NPNs and PNPs are where they are supposed to be.
  • D1 is backwards.
sbelyo  
#4 Posted : Friday, May 9, 2014 8:37:21 PM(UTC)
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Will do... Thanks Brian. I'll post pics if that's not the case
sbelyo  
#5 Posted : Friday, May 9, 2014 8:40:56 PM(UTC)
sbelyo

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If D1 lights up it's not backwards correct?
sbelyo  
#6 Posted : Saturday, May 10, 2014 5:18:33 PM(UTC)
sbelyo

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I figured it out. All transistors and diodes were correct. It turned out to be user error! Voltage across R8 was 0 adjusted it to 0.300 and got the right output voltage.

I lifted the pads for VR2 while removing it thinking that was the initial problem. I put a 3.2K ohm 1/4W metal film resistor in R2 and now I get a rock solid 5.6 Vdc

It's amazing what happens when you double check the simple stuff!
avr300  
#7 Posted : Sunday, May 11, 2014 6:01:30 AM(UTC)
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What will it be used for?

Anything involving the old (the first) Trident(s) 5.6v is a little to the high side.
sbelyo  
#8 Posted : Sunday, May 11, 2014 10:38:25 AM(UTC)
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Originally Posted by: avr300 Go to Quoted Post
What will it be used for?

Anything involving the old (the first) Trident(s) 5.6v is a little to the high side.

only a teleporter. That should be ok right?

avr300  
#9 Posted : Sunday, May 11, 2014 2:00:16 PM(UTC)
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It should be just fine.
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