Green Bean assistance needed!

[FuzzTony]

Hey guys,

I'm having a little trouble with a Green Bean build.  This is only my 4th build ever, and the first time I've run into a problem that I haven't been able to solve through closer inspection & internet searching.

Issue:  no sound at output. 

I've built an audio probe and have been following the schematic.  Everything seems fine until the part I've outlined in red:


Pin 2&3 of the 4558 have audio loud & clear.
Pin 1 has very faint audio.

C3 has good signal on one side, faint on the other.

I've measured my drive pot and it's functioning correctly, but again, lug 2&3 good audio, lug 1 very faint.

Faint/no audio following that section.

I did notice that it appears I have audio on pin4 of the IC...  I'm a noob, but I was not expecting that.

I quickly checked voltages on the IC, and all pins were around 8.6.  I could make a more precise list if that would be helpful.

Any suggestions would be appreciated.   

[mgwhit]

You should have close to 9V on pin 8, 0V on pin 4 and about 4.5V on the other pins.  First, confirm that pin 4 has continuity to ground.  Next check the orientation of C13 and C11.  Then confirm the values of your voltage divider resistors (R18, R19).  They should both be 10K.  Make sure one isn't another multiple of 10 -- that's an easy mistake to make.  After that I recommend looking for solder bridges around your power section and IC.  Good luck!

[FuzzTony]

Wow - thank you so much! 

First, confirm that pin 4 has continuity to ground. 

That did it!  Looks like I had a bad solder joint under pin 4...  it was going nowhere.  Redid that one and am now in Green Bean heaven !!!!   

[TGP39]

Good call Mgwhit.

[mgwhit]

Excellent.  Have fun!