Signs of MIJ OC-2 voltage limiter mod?

[SirTarquin]

Just got a MIJ Boss OC-2 (from 1985, from what I was told) in great condition. I've been reading a lot about these vintage Boss pedals needing 12v instead of 9v when they specified using an ACA adapter, like this one does. But I've also read some people have gone in and modded them to work directly with 9v power. The previous owner got it second hand as well and was not told whether it's been modded or not. Does anyone know of a way to confirm whether it's been modded without having to physically opening up the back of the pedal and looking? I just don't want to risk blowing the pedal by running 12v into it if it's been modded to only run on 9v.

 

[sunbeast]

There is no way to know if it was modded without opening it up. Here is a page explaining the mod for all ACA pedals (and hopefully will help you tell if this OC-2 has been modded): Modifying old Boss ACA pedals to PSA specs – stinkfoot.se

 

[SirTarquin]

I think I might have found a less invasive way. I currently have a fresh 9v battery in it. I've read that if the pedal is not getting the power it needs, the top LED will be dimmer. So I tried plugging and unplugging a 9v supply in and out of it and it got visibly dimmer when plugged in and brighter when it ran off the battery. Pretty sure that's a sign it hasn't been modded.

 

[sunbeast]

I think I might have found a less invasive way. I currently have a fresh 9v battery in it. I've read that if the pedal is not getting the power it needs, the top LED will be dimmer. So I tried plugging and unplugging a 9v supply in and out of it and it got visibly dimmer when plugged in and brighter when it ran off the battery. Pretty sure that's a sign it hasn't been modded.

Why not just open it and see? It's only 4 screws! Though you are right that if the change between battery and power supply is that clear then it probably hasn't been modded. A fresh battery will give out more than 9V in most circuits, but probably not so much more that you'd see that kind of difference unless it was throttled internally.