True bypass or buffer?
In terms of troubleshooting I would further divide all effect pedals into two categories: Those with true bypass and those with a buffer.
Pedals with a buffer, like you can find it in all of the Boss and Ibanez pedals, you can examine if the power supply is interrupted.
Because of the buffer you won’t get an audio signal even if the pedal is switched off when no power is applied. First you connect the pedal to a power supply and try out if it works. Than you connect it to a battery and try it again. If the pedal works with one of the two possibilities, the battery clip or the power supply jack is the source of error.
Of course, you should also examine the board for burns or unusual colorings. This may be a hint on a defective component.
It is also important to make sure that the LED is lit. If it stays off it is most likely that the power supply is damaged. But even if the LED is lit it is possible that the switch is defect. And if you have connected a wrong power supply you should always change the suppression diode of the power supply.
If your pedal still is not working you could also try to change the IC. At the latest here, the defect should be resolved.
Before changing the IC, it is pretty important to measure all braid connections. By looking closely, you will find out if a trace, that has been burdened mechanically by a jack, on the circuit board got broken. With a small piece of flex, you can easily bridge the respective parts.
Pedals with true bypass
In difference to buffered pedals, true bypass pedals are supposed to let the signal pass even if they are switched off.
If you cannot hear any signal, the footswitch is defect.
Concerning true bypass pedals, it makes sense to measure all wiring connections of the circuit board with a multimeter.
Even well-known manufacturers sometimes sell pedals with a cold solder joint at the footswitch connection. I already got bought two of them.
That means, that defect switches are not always the sources of error. Sometimes it is sufficient to re-solder all joints at the jacks and switches.
The pots are the last weak points. But usually they do not stop working abruptly. They are more kind by announcing their breakdown with increasing crackle and white noise.
If you follow these tips, you should be able to repair almost all analog and also numerous digital effect pedals. If you fail nevertheless, don’t hesitate to ask me.
And please keep in mind never to use contact cleaner spray!
In the next part, you will learn more about the importance of the right cables when there is something wrong with your pedal.