hey so my friend let me on his MXR phase 90 M101 pedal since it was broken. Initially the pedal would not turn on. So i found a shorted out Zener diode and replaced it. the diode broken upon taking it out so i couldn't tell what the rating on it was.

now the pedal turns on, but only at the end (furthest clockwise) of the potentiometer does the effect turn on. the zener diode i replaced it with was a 5.7V 0.5W. i read somewhere that you match the zener diodes to the FET that is used. for the FET in the attached schematic they recommend a 4.7V. could this be the problem?

any ideas or ways to troubleshoot would be appreciated.

thanks

 

I was reading HERE that the zener diode value needs to be "tweaked". They mention 5.1V.
So you could just try out 5.1V and 4.7V and see how it goes.

 

sorry i meant to say it was 5.1V zener diode. thanks for the link i didn't even see the build reports down at the bottom of the page. those are very helpful.

i read that people are using reverse log potentiometers to combat the problem with only having a noticable effect at minimum resistance.

thanks for the link. and quick response. i will try some of the mods they suggest.