[solved] FM Output problem

MIDIbox FM
1

Hi Midiboxers,

after fixing my voltage issue, i still have a output problem :frowning:

It is very low and there is a lot of background noise:

Testtone:

[test.mp3](< base_url >/applications/core/interface/file/attachment.php?id=10575)

I allready checked:

5V @ Ic1 Pin 1,7; Ic2 Pin 1, 3, 6, 9

+12V @ Ic3 Pin 4; Ic6 Pin 4

-12V @ Ic3 Pin 11; Ic6 Pin 11

polarity of c1, c3, c5, c7, c11 ,c16, c18, c20 ,c22, c24, c26, c31, c32, c33, c34 = checked

replaced Ic3, Ic6 = no difference

FM-Interconnection test = passed

Any suggestions what could be the fault?

May some other capaciator?

Thanks for your help

Best regards

Marxon

2

Hi again :smile:

I was reheating every soldering when i noticed a missing trace on my board.

post-4098-0-65100600-1365511040.jpg
post-4098-0-65100600-1365511040.jpg312×158 12.9 KB

post-4098-0-83636500-1365511053.jpg
post-4098-0-83636500-1365511053.jpg274×176 13.3 KB

It is the 5v trace which goes to the bridge and from there to the rest of the board.

But like i said in my last post there was 5v on Ic2 Pin 1, 3, 6, 9

even without the missing trace?

So the new question is: where do the 5v come from?

3

It´s me again…

But there are good news

Finally it works now :smile:

Good output, low background noise

I simply forgot to connect audio gnd.

Slap in my face…

And the 5v issue: who cares :wink: