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Old 18th October 2012, 08:22 AM   #1
yd1cvj is offline yd1cvj  Indonesia
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Default LM3886 unussual pcb

Hi, does anybody use this PCB for LM3886. I'm going to build 2 parallel/pcb. PCB it self for stereo and thickness of pcb 2.6mm.

Just wonder if I can use same componen value as it's printed. And input line are + and - instead L and R. The + and - goes to same pin number, so I conclude it is not bridge.

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Old 18th October 2012, 08:39 AM   #2
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Do you have a schematic for this PCB??????
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Old 18th October 2012, 01:21 PM   #3
AndrewT is offline AndrewT  Scotland
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Attach a higher resolution pic.
Then we can open the pic and see the detail more easily.
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Old 19th October 2012, 12:33 AM   #4
yd1cvj is offline yd1cvj  Indonesia
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@madtecchy : I do not have the schematic.

@AndrewT : some of copper line is covered black paint, I will try to get good camera.
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Old 20th October 2012, 07:21 PM   #5
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or use document scanner, they are great for PCB "photographing"
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Old 20th October 2012, 07:37 PM   #6
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Why shouldn't it be a bridged module ?
As I see, the ICs are held parallel to the board, because there are no trough holes made for the ICs.

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Old 21st October 2012, 01:22 PM   #7
yd1cvj is offline yd1cvj  Indonesia
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The black paint is very perfect to hide some copper track even scanner can't "see" it . I draw the scheme and use multimeter to trace connection of some point and get this:
(Sorry the R18K and C 1uf is connected to pin no 8 not to output)
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I build one channel w/ 30 volt+/-DC and result is good, eventhough I do not put the C = 1 uf.
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Last edited by yd1cvj; 21st October 2012 at 01:48 PM. Reason: pin no 8
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Old 25th October 2012, 08:05 AM   #8
yd1cvj is offline yd1cvj  Indonesia
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I have qustion about feedback R=100k, and biased R=4.7k . I saw other scheme ussualy feedback R=20K.
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Old 25th October 2012, 09:14 AM   #9
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by yd1cvj View Post
I have qustion about feedback R=100k, and biased R=4.7k . I saw other scheme ussualy feedback R=20K.
biased R=4.7k what does that refer to?

Link to a schematic and use the schematic component labeling to make clear what you are talking about.
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Old 25th October 2012, 09:24 AM   #10
yd1cvj is offline yd1cvj  Indonesia
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Quote:
Originally Posted by AndrewT View Post
biased R=4.7k what does that refer to?

Link to a schematic and use the schematic component labeling to make clear what you are talking about.
Andrew T,
Sorry . Actually I'm refer to the 4.7K in my drawing scheme.

Also I wonder is the elco =1uf is really needed ?
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