Boss DD2 Works with Battery and not with Power Supply

[dpresley58]

The problem is in the subject.

I've desoldered, cleaned and tested the plug and it checked out. There's a small board with what seems to be a cap along with a component I'm not familiar with. When checking the schematic (http://www.freeinfosociety.com/electronics/schemview.php?id=126), it seems to be some sort of coil with another cap.

If anyone has any thoughts as to why this isn't working, and/or what that component is I'd appreciate the help.

[cd]

That would be some sort of coil based RFI filter, whose technical name I cannot for the life of me remember right now.

Either way the battery still goes through that part, so if it was bad it wouldn't work with the battery either.  I would check the ground and power wiring of the little board.

Coincidentally, I have a DD-2 busted apart on the table right now, I will take a look at it and see if anything obvious pops out at me.

[Paul Marossy]

Umm... maybe a stupid question, but are you sure that your power supply is the same as what your pedal is expecting to see? In other words, center negative pedal + center negative power supply.

Is it on a shared power supply? I have an Arion analog delay that refuses to work on anything but its own power supply. Maybe you have the same sort of situation?

[dpresley58]

Thanks for the suggestion, but the power supply is a Boss unit used solely for this effect. Good question, though.. I should hook it to one of my own Boss pedals to make sure of it. The owner had another band member loan him a supply and still no dice.

[Paul Marossy]

Here's another idea: Are you sure that the wall wart is putting out any voltage?

[analogmike]

I had one here for a mod with the same problem. It's not an easy fix, we replaced the regulator, zener, etc and gave up

[TheBigMan]

I've seen more than one Boss pedal of that generation where it's the DC jack that's gone bad.  It refuses to switch anymore and gets stuck in one place, although usually they then work only with a PSU.

Try hooking up with crocodile clips to the back end of the DC jack with the adapter.  If that works then it's the jack that's faulty.

[any]

I've seen more than one Boss pedal of that generation where it's the DC jack that's gone bad.  It refuses to switch anymore and gets stuck in one place, although usually they then work only with a PSU.

Try hooking up with crocodile clips to the back end of the DC jack with the adapter.  If that works then it's the jack that's faulty.

I can verify that with many boss pedals going through my hands, I had a GE-7, TU-2, DM-2 and PEQ-4 with exactly that problem
(only on battery, not on wart), a new dc jack cured it in all those cases.

[cab42]

My DD-2 has the exact same problem. I have "solved" the problem making a lead from the PSU with a battery snap indstead of usual jack and snapping it on to the pedal snap.

Regards

Carsten

[Paul Marossy]

Hmm... sure sounds like the DC jack is in question!