Yes all of my other BOSS pedals default to OFF which seems more logical but my PH-2 defaults to ON and it's pretty annoying. I'm powering it with an adapter. I'm not sure how it behaves with 9v battery, probably the same.
So is there any mod to change this? Does anyone else have a PH-2 that behaves this way?
Q4 and Q5 are the main elements in the flipflop. Starting "ON" is not a fault - it's just what some of them do.
Next step is to leave Q4 and Q5 swapped, then progressively swap the following pairs then try it: R59 - R60 C41 - C42 C39 - C40 R58 - R61 (these are a bit hard to read on the schem - make sure they are both 56k)
You can make the collector resistors of Q4 and Q5 "a bit" asymmetric. I don't have the schematic but if you lower the resistor from the side that connects to the LED to 47k will do it.
I'm really not sure why BOSS would decide to start some pedals on but others off. I'd love to know the reason.
Ok thanks Laurie for the next steps which I'll give a shot tomorrow.
It's not intentional - it's just variances in the components. I'm actually quite surprised the Q4-Q5 swap didn't work - they are the two "legs" of the flip flop and swapping the transistors has worked every other time I've seen it tried.
cctsim has the next step if my suggestions don't work. The resistor you want is R57 (factory spec is 56k)
PS: thanks for the PM. It's best to just put your request on the forum and give everyone the chance to respond.
I had to go through a painful swapping procedure on my new BD-2 to change the state, meaning that I swapped every component on the flip flop to get it working.
It was the last two resistors R45 and R48 that reverted the state. The problem is that you don't know which components cause due to tolerance the balance to shift to the off-state.
Ibanez uses the asymmetric trick with a 10k and 22k as collector resistors which leaves no room for tolerances. The 10k is on the side where the LED is connected.
PH-2 defaults to ON, any mod to fix this?
Posted - 02/24/2009 : 21:03:42
