Boss DD-3 modification

[Liumander]

Hi, I got a second hand DD-3 and when I plug the input cable it automatically turns on (red LED on), no matter if it was off when I unplugged it, after that I can turn off if I step on the switch. I don't know if that's the way it's supposed to behave, but I want it to be off when I connect it then I can choose if I want it to turn on or not. But it's annoying just plugging it and stepping to switch it off everytime. Do you have an idea of how can I do that? Or whether it should or shouldn't do as it now does? Thanks

[ElectricDruid]

Do you know which version it is? There have been three, I think; DD3A, DD3B, DD3C.

Once we know that and we can find a schematic we might be able to answer your questions.

[Liumander]

Do you know which version it is? There have been three, I think; DD3A, DD3B, DD3C.

Once we know that and we can find a schematic we might be able to answer your questions.

I think it's B. I've checked on internet and it says that the B is the only one made in Taiwan. And mine is.

[ElectricDruid]

Ok, I *think* this is the schematic for it:

https://ia600203.us.archive.org/22/items/boss_DD-3A_SERVICE_NOTES/DD-3A_SERVICE_NOTES.pdf

The 3B uses a different power jack, but is otherwise the same as the 3A - if I'm reading the Stinkfoot article correctly.

Looking at the circuit, the footswitch is simply debounced and then passed to the gate array chip, so the Effect On/Off behaviour is hard-coded into the logic of that chip and there's nothing we can do about it, sorry.

What would be possible would be the addition of some sort of "auto-off" circuit. You could wire a transistor as a switch across the footswitch, and then set up a little circuit to switch it on briefly (say) 100msecs after power on.

[Daner56]

I think this problem should be fixed by removing the footswitch and adding some kind of "auto-off" circuit to set up a small circuit.