Sun King - Bizzare Voltages

[JammyDodger]

Hey All,

I have finished up my Sun King.  I built it exactly per instructions. (Well, maybe not since it doesn't work).  I am getting some very strange voltages on the IC's

Pin      IC1 - TL072              IC1 - TL072               IC3-ICL7660SCPA  
  Measured   Expected   Measured   Expected      Measured   Expected[/b]
1   1.35           4.45      -3.66         4.52            8.54          8.88
2   1.35           4.47      0               4.47            4.29         4.55
3   0.958         3.43      0                4.46                0         0
4   0               0           -7.92       -8.46            -3.97       -4.15
5   0.25           4.45      0               4.45            -7.92       -8.47
6   0.325          4.46      0              4.46              3.56        3.99
7   7.94           4.45      3.68          4.41              4.15        5.33
8   8.56           8.88      15.14       16.03              8.53        8.88

Diodes and Ele caps seem to be oriented correctly.  Any suggestions?

[madbean]

Double check that you indeed have 27k on both R25 and R26.
Look for tiny solder bridges....use a magnifying glass if you have one. I use one all the time.
Is either IC1 or IC2 hot when you touch it?

[Ang3lus]

what would happen if you'd have used 30k instead of 27k ?

[madbean]

If you use 30k on both, then its okay. These act as voltage dividers so it's important that both are approximately the same value. If one were significantly less, then Vb will not be the proper voltage which will throw everything off.

I did this very thing over the weekend. I was building up a different project that needed two 10ks. I accidentally used 1k for one of the resistors and the result was improper voltages and a terrible intermittent sound.