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Confirmation on Diode Polarity on Jims Audio FC07-0005 LM4780GF PCB!?

TheLaw

Sep 27, 2010
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Hi,

I have a quick question. The pictures are of the front and rear side of the board I'm dealing with. If you look in the lower left-hand corner, there is a place for 4 6A diodes to form a bridge rectifier. The silkscreen is confusing me, and I don't know exactly how split supply bridge rectifiers work...so...I'm not sure which way the diodes should go in.

There are no pictures on the web unforuntealty.

I am assuming that all of the cathodes (-) are facing away from the board and all of the anodes are facing the 4 places for the 4700uF caps.

I'm just confused because the silkscreen on the right side is oddly printed.

4bf4cb2e.jpg



32cc43ed.jpg


Thanks much.
 

Resqueline

Jul 31, 2009
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Cathodes should be connected to the positive end of the supply, and anodes to the negative end. Here's what it should look like.:
 

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TheLaw

Sep 27, 2010
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So like this, correct?

And thanks a lot!
 

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TheLaw

Sep 27, 2010
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Wow you know what. I'm sorry for making this thread. I should have looked harder at the Jim's Audio image. The silkscreen on my own board is kind of funky, but looking at the picture, it's pretty obvious. Thanks.
 

TheLaw

Sep 27, 2010
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Oh did you fill in the white there on the board?

Sheesh, I'm even more confused! Anyway, thanks.
 

Resqueline

Jul 31, 2009
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Yep, it's correct that way.
I did edit the pictures I posted. I just used Paint and moved bits & lines & pieces around. The original was indeed funky.

No worries mate, it's perfectly in order to post a question about this. The cap's & the IC would blow up if you got it wrong.
I also edited the title so the issue will be easy for anyone else to search & find.
 
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TheLaw

Sep 27, 2010
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Thanks. I just installed. Sheesh, I've never used 6A diodes before. I'm using 6A10s. They really mean business!
 

Resqueline

Jul 31, 2009
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With spec's of 6A @ 75 deg.C ambient, 400A surge, and 1000V PIV I can see what you mean. I also think this size was called "bullet rectifiers" back in the days. :)
 
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