Did I Burn Something Up on Boss DD-3? At a Loss...

[drumnbum]

Picked up a used Boss DD-3.  Worked great with DC power, but the battery snap was broken.  I've tested and used it several times on DC, so I know it worked flawlessly before. 

Went to replace the battery snap.  Pretty straightforward job (I've done others before).  However, the snap's wires I had were a little too short, so I simply cut off the existing broken snap and wired them together with the new snap (typical tin each wire, wrap together, solder together and then heat shrink them.  Red to red, black to black). 

Anyhow, I did that and before reassembling everything I wanted to check the job before moving on to modding it.  When I went to plug it in, in my haste I accidentally plugged the same cord into the input and output and hit the on/off switch just to see if the LED (which worked fine previously) would light up.  It did, but I realized I didn't have the cables connected properly, so I plugged everything back in the correct way and now I can't get the LED to light or any sound from the unit. 

I decided to remove the battery and simply run on DC to see if this worked (thinking my battery snap install may have been the issue).  Same thing - no sound....well, I DID get a big hum which would indicate ground issues (all components are outside the Boss metal enclosure still, so I expect SOME hum). 

So I just decided to unsolder the battery snap completely to eliminate that variable and it didn't change anything.  Can't get the light to work, can't get any signal to pass.  However, i AM able to sometimes hear the delay clock making noise as I adjust the feedback and delay time knobs. 

Can anyone offer any advice at all for troubleshooting this?  I'm at a loss.

[GibsonGM]

Nice, drum!  LOL (I really am laughing, but not at you - welcome to the forum!). 

No, plugging your guitar cord from input to output won't harm anything. 

The only time I could think that it MIGHT cause damage would be if you had a bad input cap AND output cap, that allowed some kind of shorting out of bias voltage, but I have to reach to think that would be in any way likely.


Plug a cord into the input jack.   Take a meter (DMM) and check the battery terminals (wires....).   What is the resistance between black and red?   Or, if you have a continuity check (beeper), use that.     If you have a VERY low resistance there, it means a power supply short - what you were worried about.  No low resistance, no short.    Also, be sure the jacks are tight.  I've seen ground wires not making contact on Boss's due to this.

On the Boss stuff, it's usually more to do with the switch.  Either the little switch itself, or one of the JFETs that it controls.   I vote for checking w/DMM, and putting the new battery connector back on.  Then move to the next step...come back, tell us what happened... 

[drumnbum]

Update:  I fixed it.  Two things were going on:  1st, the output wire connection had been stressed and was cutting in and out.  In my haste, I hadn't noticed this.  and 2nd, the pedal absolutely needs the jacks at least grounded to the enclosure to not hum insanely loud. 
Easy enough.  Just thought I'd lost my mind hah.