Power supply issue
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- Old Hand
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#1 Power supply issue
I have a phono amp which requires two + power supply rails .
The power supply is configured with yellow and black going to + on separate bridge rectifiers . And the dc+ rail of the br connecting to plus on separate capacitors.
The capacitors have linked ~ terminals . The orange and red wires of the transformer are soldered to the copper bar connecting the negative terminals of capacitor .
I would expect this to give me 2 positive rails at approx 26v
One is as expected the other is only 8v
Anybody know why?
The power supply is configured with yellow and black going to + on separate bridge rectifiers . And the dc+ rail of the br connecting to plus on separate capacitors.
The capacitors have linked ~ terminals . The orange and red wires of the transformer are soldered to the copper bar connecting the negative terminals of capacitor .
I would expect this to give me 2 positive rails at approx 26v
One is as expected the other is only 8v
Anybody know why?
- pre65
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#2 Re: Power supply issue
No.
But, as we have mentioned before, a diagram might make things more clear.
But, as we have mentioned before, a diagram might make things more clear.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#3 Re: Power supply issue
Generally I would expect the transformer to be connected to the AC terminals of the bridge. As Phil said try and draw what you have.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#4 Re: Power supply issue
With the rectifiers disconnected, what AC voltages are at the transformer? I had a similar issue many years ago with an incorrectly labelled transformer. There was 0, 9 and 14 volts measured, the label said 15, 0, 0,15. With 9VAC going to the one side and 14VAC going to the other side of the rectifier, 8VDC volts is all that I got...
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- Old Hand
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#5 Re: Power supply issue
I’ll try rephrasing
I’ve got a transformer with 2 secondaries
I’ve got my 2 ac secondaries attached to the + side of two separate bridge rectifiers . They both show 18v ac n accordance with the specs .
Measuring the separate bridge rectifiers at the dc terminal I’ve got one showing 26v and one showing 8v
I’ve got the 0v for both secondaries attached to a copper bar which is attached at each end to a separate capacitor .
Why are both + terminals not showing 26v , something wrong or electrical law are not privy to?
Also anybody have examples of power supply with two 24v positive rails?
I’ve got a transformer with 2 secondaries
I’ve got my 2 ac secondaries attached to the + side of two separate bridge rectifiers . They both show 18v ac n accordance with the specs .
Measuring the separate bridge rectifiers at the dc terminal I’ve got one showing 26v and one showing 8v
I’ve got the 0v for both secondaries attached to a copper bar which is attached at each end to a separate capacitor .
Why are both + terminals not showing 26v , something wrong or electrical law are not privy to?
Also anybody have examples of power supply with two 24v positive rails?
- pre65
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#6 Re: Power supply issue
Something wrong.
Seems connecting the two secondary's to two bridges should be OK, if you have the wires in the right place, but how do you get the 0v connection ?
Is the transformer 0-18v + 0-18v ?
Still need a diagram to make full sense of what you are doing.
Seems connecting the two secondary's to two bridges should be OK, if you have the wires in the right place, but how do you get the 0v connection ?
Is the transformer 0-18v + 0-18v ?
Still need a diagram to make full sense of what you are doing.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- IslandPink
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#7 Re: Power supply issue
Why are they not attached to the ~ and ~ terminals ?Daniel Quinn wrote: ↑Sun Jul 31, 2022 12:58 pm I’ve got my 2 ac secondaries attached to the + side of two separate bridge rectifiers .
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#8 Re: Power supply issue
Don't try rephrasing just draw a simple picture.
As close as I can make out from your text the transformer should not be connected to the + on the bridge rectifier.
As close as I can make out from your text the transformer should not be connected to the + on the bridge rectifier.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#9 Re: Power supply issue
Last try. Is there any reason other than trying to bend us to your will that is stopping you from posting a simple diagram?
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#10 Re: Power supply issue
I’ve still not figured how to do it and was being lazy .
The reason I have not used the negative terminal on the bridge is because I need two positive 26v
The reason I have not used the negative terminal on the bridge is because I need two positive 26v
- shane
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#11 Re: Power supply issue
This is the bit I’m struggling with. In my (very limited) experience, a bridge rectifier has two AC terminals, sometimes marked ~, which connect to each end of the transformer secondary, and a + and a - terminal for the DC output. If you have two secondaries and two rectifiers it would often be the case that the two DC - terminals are connected to the same earth bar, but I can’t understand why you would connect either end of the secondary to the + terminal.Daniel Quinn wrote: ↑Sun Jul 31, 2022 12:58 pm I’ve got my 2 ac secondaries attached to the + side of two separate bridge rectifiers
As everyone keeps saying, a diagram of what you have would really help!
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- pre65
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#12 Re: Power supply issue
How to wire a bridge rectifier.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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- Old Hand
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#13 Re: Power supply issue
I know how to wire a bridge rectifier ! But you wire it normally and you get a + rail and a negative rail . This works fine for the vast majority of applications .
I need a power supply with two plus rails at 26v .
I need a power supply with two plus rails at 26v .
- pre65
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#14 Re: Power supply issue
For fuck sake, just do a diagram if you really want our help.
How hard can it be ?
Just a rough diagram showing connection points and wire colours will do.
Again, how are you configuring the 0v connection ?
How hard can it be ?
Just a rough diagram showing connection points and wire colours will do.
Again, how are you configuring the 0v connection ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#15 Re: Power supply issue
Well just do what you know to do twice.Daniel Quinn wrote: ↑Sun Jul 31, 2022 2:47 pm I know how to wire a bridge rectifier ! But you wire it normally and you get a + rail and a negative rail . This works fine for the vast majority of applications .
I need a power supply with two plus rails at 26v .
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.