Boss OS-2 won’t turn off

[didgy]

Hi everybody!

I created a weird problem to my Boss Overdrive/Distortion OS-2 while attempting to add a switch to select the default initial state. While trying to prove I got the right two 56k resistors to control the initial flip-flop state, I notice the pedal would now start on instead of off and could no longer be turn off. At least, this is better than can't be turn on... My first guess was that the footswitch was the problem, but using a tester, it seem to work normally. I then suspected that one of the two 470pf capacitors (C32 and C33) used in the flip-flop part of the circuit could have died, but replacing them didn't make a difference. Since I had no other real idea, I also tries to change the 2 220pf (C21, C34), still no luck... I'm still new to the world of electronics, so I don't know what to do next... I did successfully modded 14 other boss pedals the same way, so I really want to understand what went wrong. Anyone have an idea?

This is the schematic for the pedal:
http://www.freeinfosociety.com/electronics/schematics/audio/pictures/bossos2.gif

Thanks for the help!

[duck_arse]

as bluebunny might say, welcome. also, head over to geofex.com, and search for the anatomy of the tubescreamer, among other docs. in it [I think it's this one], RG disects the boss flipflop circuit, very instructive as to which 56k will do what.

[didgy]

Hi duck_arse,
Thanks for the reply. At this point, my concern is to get the footswitch to work again and hopefully learn how I cause the problem. I'm pretty sure the right resistor to control the initial state are R50 and R52. My guess is that while trying to prove I had the right resistor by using a 100k not solder resistor, I slip and shorted something...

[didgy]

So I decided go an other way and converted the pedal to a true bypass switching system using a 3pdt switch. Work perfectly!