Repair ?'s for Boss Dm-2 Delay

[pineder]

Hello!

I'm new to this forum and I'm not sure if I posted this in the correct spot, but maybe someone can help me out.  I have a vintage original Boss Delay Dm-2 (Japan).  It works great except for one thing,  it will not work with just a battery in it.  I have to have it plugged in the wall if I want to use it.  Could something be wrong with the battery connector?  I have some soldering skills, but that's about it.  Could someone please respond with some possible solutions to the problem?

Thanks,
Joseph Pender

[Joep]

I don't no for the DM-2 specific, but normally there is a switching mechanism in the wall-wart connector that swiches of the battery as soon as you plug in the wall-wart. It looks like this mechanism is not working properly.

[Nasse]

I too have not seen schematic but if there are some components like protection diodes, smoothing caps or voltage regulators after external DC jack they may be broken.

[Sonny ReVerb]

Here's a schematic:

http://www.generalguitargadgets.com/boss_schem.html

Sonny

[afranks]

I'd say there's a 90% chance it's a bad battery snap (connector).  Try replacing it with one from Mouser or Radio Shack, but make sure the leads are at least as long as those on the one you're removing.  Oh... you may want to stick to using the vinyl encased 9v snap, rather than the more durable plastic bodied kind.  I've had trouble fitting the plastic ones into Boss pedals.  There's not a lot of room in there.

In the event that it's not the snap, it's probably the DC jack.  Most often it's just the solder joints that crack, and need resoldered.  If that doesn't work, you'll need to replace the jack.  Mouser should have a decent replacement.

-alan

[Mark Hammer]

It is possible for oxidization or something else to interfere with the contact between the battery lug and the V+ lug on the barrel connector.  You should see a red lead from the battery connector going to the barrel jack.  De-solder it and reconnect it to the hot lead of the barrel jack.  If you do not have battery power under those circumstances, then the problem is situated somewhere other than the socket itself.

If you do have a problem with a flawed battery connector, I recommend taking a look at the "make your own battery snaps" article here to make something a little more robust: http://hammer.ampage.org/index.cgi?I=20

Just note that you will have to right-clock on the link to the pdf document, save it to disk and open it up from there.  Don't know why, you just have to.