TS 10 voltages

[Jered]

 Why would I be getting between 4 and 4.5 volts on all the pins of the 4558 except for pin 4 which has 0 volts and pin 8 which has 9 volts. This is a Ibanez ts10 tube screamerThanks for your help

[GibsonGM]

Because of the bias voltage applied to them from VRef, most likely.  That is a normal looking bias voltage (about 1/2 supply).

[GibsonGM]

http://www.freeinfosociety.com/electronics/schemview.php?id=1086

[PRR]

> Why would I be getting between 4 and 4.5 volts on all the pins of the 4558 except for pin 4 which has 0 volts and pin 8 which has 9 volts.

Where would you like them to be?

Check the chip pinout.

Pins 4 and 8 are Power.

In pedal-work we often power with zero and +9V, so that's expected.

Pins 1 2 3  5 6 7 are "signal". Audio swings both-ways. Our 0/9V power is one-way. The trick is to "bias" the signal pins UP to "about half-way". Now they can swing both-ways around the half-way point. Audio gets through.

A side-note. In many schemes the "input" pins (1 2 5 6) are biased with a large resistor. When poked with a meter, the voltage drops. Generally if the "output" pins 3 7 are at a nearly-right voltage, you may disregard any slightly-low voltage measured at the inputs. They are probably right (as shown by happy output voltage) except when you meter-poke them.

[Jered]

 Oh ok. So those voltages look normal? The pedal is not working so I thought I would start with the IC volts. Thanks guys

[GibsonGM]

Have you got an audio probe yet?  Chances are pretty good that there's a problem with a pot or jack, and the audio probe can help you spot it

http://www.diystompboxes.com/pedals/debug.html

[Jered]

  Thanks guys I found it. Cold solder joint.