EQD Sea Machine - No sound when engaged.

[analog_memories]

First post to debugging.  Be gentle please. :)

I built a EQD Sea Machine via the layout for the Madbeans Gravity Wave using the schematic from Alex Madbeans Gravity Wave.

Here is a picture of what I have done:
image1.JPG

So, in bypass I get a good clean signal, but when engaged I get nothing.  I did all the normal troubleshooting and did find a couple of caps and one resistor that were the wrong value.  Changed them out and still, nothing.

I checked to see if I am getting voltage out of all the chips and I believe they are correct.  Any help you guys can lend me would be greatly appreciated.
 
IC 1 - TL072
Pin 1 - 1.42v
Pin 2 - 1.42
Pin 3 - 1.38
Pin 4 - 0
Pin 5 - 1.26
Pin 6 - 1.38
Pin 7 - 1.39
Pin 8 - 9.08

IC 2 - PT2399
Pin 1 - 5.04
Pin 2 - 2.52
Pin 3 - 0
Pin 4 - 0
Pin 5 - 2.66
Pin 6 - 2.45
Pin 7 - 3.94
Pin 8 - 3.93
Pin 9 - 2.52
Pin 10 - 2.52
Pin 11 - 2.52
Pin 12 - 2.49
Pin 13 - 2.52
Pin 14 - 2.52
Pin 15 - 2.52
Pin 16 - 2.52

IC 3 - LM324
Pin 1 - Variable
Pin 2 - 4.47
Pin 3 - Variable
Pin 4 - 9.08
Pin 5 - 0
Pin 6 - 0
Pin 7 - 0
Pin 8 - 0
Pin 9 - Variable
Pin 10 - 4.51
pin 11 - 0
Pin 12 - 4.52
Pin 13 - 4.54
Pin 14 - Variable

IC 4 - TL072
Pin 1 - 1.44
Pin 2 - 1.41
Pin 3 - 1.42
Pin 4 - 0
Pin 5 - 1.42
Pin 6 - 1.43
Pin 7 - 1.43
Pin 8 - 9.08

[induction]

Your biasing is messed up. Check the jumper connected to pin 3 of the upper TL072 or the two 10k resistors just below the same TL072. If you don't spot the error, post pictures.

Based on your voltages, even if you do find a problem in that area, it might not be the only one. So if you do fix something and it still doesn't work, remeasure your voltages to see if anything changed.

[analog_memories]

Found a spot that was supposed to be cut and wasn't all the way.  However, still no sound.  I can hear oscillation noise when I turn the pots.

Here are the new readings from IC 1

1 - 8.53
2 - 8.53
3 - .14
4 - 0
5 - 6.9
6 - 7.44
7 - 7.47
8 - 9.08

IC 2 - PT2399

1 - 5.04
2 - 2.52
3 - 0
4 - 0
5 - 2.82
6 - 2.49
7 - 3.96
8 - 3.99
9 - 2.57
10 - 2.56
11 - 2.56
12 - 2.56
13 - 2.57
14 - 2.58
15 - 2.60
16 - 2.57

IC3 - LM324

1 - variable
2 - 4.48
3 - variable
4 - 9.08
5 - 0
6 - 0
7 - 0
8 - 0
9 - variable (4.8 to 5.3)
10 - 4.50
11 - 0
12 - 4.52
13 - 4.56
14 - variable (3 to 5)

IC4  - TL072

1 - 8.45
2 - 8.15
3 - 8.53
4 - 0
5 - 8.53
6 - 8.47
7 - 8.50
8 - 9.08

Also, the rate LED is/has not been working.

Attached are pictures of the board.

image3.JPG
image4.JPG
image5.JPG
image6.JPG

Let me know if you need more detailed pictures.

Thanks again!

[analog_memories]

I found a fault with my wiring of the pots to the board.  I had the Dim and Shape switched around.  I found that I am not getting voltage to pin 8 on the IC3 and not getting any voltage on pins 5 and 7 as well.

[analog_memories]

OK, here is what I have found so far.  I still need more help, I can't see where the problem is.  My earlier post has pictures of the board.

Still no sound when engaged.

IC3 LM324 pin 5, 6, 7, seem really low. I would expect higher since the output of pin 7 is to drive the Rate LED, and .59 volts is just not going to work.  here is the new updated voltage readings:

IC1 TL072

1 - 8.53
2 - 8.53
3 - .14
4 - 0
5 - 6.9
6 - 7.44
7 - 7.47
8 - 9.08

IC 2 - PT2399

1 - 5.97
2 - 2.99
3 - 0
4 - 0
5 - 3.41
6 - 2.94
7 - .77
8 - .78
9 - 2.99
10 - 2.99
11 - 2.99
12 - 2.99
13 - 2.99
14 - 2.99
15 - 2.99
16 - 2.99

IC3 - LM324

1 - 4.53
2 - 4.48
3 - 4.59
4 - 9.08
5 - .56
6 - .59
7 - .59
8 - .59
9 - 6.54
10 - 4.52
11 - 0
12 - 4.52
13 - 4.56
14 - 4.60

IC4  - TL072

1 - 8.45
2 - 8.15
3 - 8.53
4 - 0
5 - 8.53
6 - 8.47
7 - 8.50
8 - 9.08

[induction]

Sorry I missed the picture in your first post.

The 10k just south of pin 5 of the top TL072 is connected one row south of where it should be. Fix that, test, measure voltages again.

[analog_memories]

Thanks for pointing that out induction.  I have been staring at this board for week.  I got that fixed and I have sound when engaged.  I am getting 4.4v on pin5, 6, 7, and 8 on IC3.  I had the LED wired backwards, but now that is working.

The pedal is a bit noisy, but for what I am doing, it will work just fine for now.  I will work out the mods later .

Thanks induction for you help!