debug for tonepad small clone

[duck0872]

Hey guys,

Building another one of these and having some problems.  I'm getting a signal through the board but no chorus effect.  No solder bridges, caps trans and ic's all oriented correctly.  Trimpot has no effect on the signal.  Here's my voltage readings

power at supply- 12.32
at board- 12.26

d1- c 2.38
      a 3.17

d2- c 8.59
      a .03

q1 2n5087 - e 2.44
                  b 1.38
                  c .03

q2 2n5088- e 11.45
                 b 12.19
                 c  12.34

q3 2n5088- e 10.17
                 b 8.85
                 c 10.91

IC 4558- 1  4.80      8  8.97
             2  4.84      7  4.49
             3  3.57      6  4.49
             4  .02        5  4.36

IC LM358-  1  7.32     8  10.13
                2  7.90     7  8.51
                3  7.72     6  7.53
                4  7.93     5  7.49

IC MN3007-   1  8.45     8  7.80
                   2  .05       7  7.78
                   3  2.36     6  8.61
                   4  .05       5  .05

4047  -       1  8.58     14  8.38
                 2  0          13  8.38
                 3  6.62     12  .08
                 4  8.59     11  .08
                 5  8.58     10  8.38
                 6  8.57      9  .09
                 7  .12       8  .10

[dwmorrin]

Building another one of these and having some problems.  I'm getting a signal through the board but no chorus effect.  No solder bridges, caps trans and ic's all oriented correctly.  Trimpot has no effect on the signal.  Here's my voltage readings

IC LM358-  1  7.32     8  10.13
                2  7.90     7  8.51
                3  7.72     6  7.53
                4  7.93     5  7.49

Pin 4 should be 0 volts.
Also, I don't quite understand your +V readings (... or "+9" connections on the tonepad schematic...) you report that as 12.34V on Q2 collector, 10.91V on Q3 collector, 10.13 on LM358, and 8.97 on the 4558.  All of those should have the same voltage.

[duck0872]

Looks like that pin 4 is missing a trace to ground, must have been eaten away when I etched the board.  I'll have to bridge it somehow tomorrow and see what happens.

[duck0872]

thanks dwmorrin, that was it.  Bridged pin 4 to ground and it works fine now.

[Kipper4]

Nice work guys.
I'm glad you've got it going.