Washburn A-AD9 delay battery heat up.

[jondoeband]

So, after several hours of re-soldering wire inside of my broken delay pedal in hopes that I could get it running again, the moment I attached a battery smoke began emanating from the board in the location of diode that I had replaced before hand and the battery began to heat up.  Fearing the worst I almost burned myself removing the battery from the clip.  Thankfully, nothing was destroyed that I can tell, but the traces around the Diode had lifted up from the board. 

I believe the problem was either
A: the previous soldering job which I did when I was much less experienced or
B: the same problem that caused the part to fail in the first place.

I should note that I have no idea what caused the diode to fail in the first place, as it might have been another part dying that caused the part to overheat.

This leads to the reason of my post.  I have two questions:
Dose this pedal still sound salvageable?

And If not, I will have the chips from the pedal still in place.  The chips are the highly sought after MN3005, MN3101 (may not work due to its proximity to the failure), An NE571N, and a TL 4558P.  Dose anyone have any recommended builds for theses chips (one that preferably dose not require the purchase of another 3005/3101 pair), and any tips on salvaging them from the board with little to no damage?

Thank you for your time.

[gcme93]

The first thing I like to check is the resistance between the two terminals you attach the battery to. I had a battery overheating like mad earlier today, i did this test and found about 5 ohms - I'd made a silly short circuit when grounding the pedal. Fixed this and it went to a far healthier 600ohms.

This is a test you can safely do with no power attached.

Secondly, which way round did you have the diode? It should be pointing towards the positive end as it's only there in case you insert the battery backwards (or more commonly use a power supply backwards). If the diode has the thin marking line pointing towards ground, all your current will short through that route and will get pretty hot I imagine. At least it will leave your circuit undamaged.

Finally, did the IC chips get warm during any of this? That seems to be one of the most straight forward ways to check whether the pedal will be okay (if it was too hot to touch, its dead but don't repeat to find out!)

Do you have a multimeter? In future it should be a lot easier to check the resistances around each part of the circuit (continuity checking) instead of just re-soldering everything "blindly" as it were. Check out the debugging page link at the top

George

[jondoeband]

Heh, I wouldn't be surprised if a short caused by the battery clip was the cause of this all.  I had replaced it a few times, and I imagine that in my inexperience I would have improperly insulated the hookup wire.

A quick check with a multimeter on the batt clip yields about 65 kohms

And yes, much to my displeasure, the MN3101 did warm up a bit, which I imagine is partially due to its proximity to the failing diode, if not the cause itself.

I should note that this pedal was manufactured under several names and is closest to this one here, Minus the switching section: http://s266.photobucket.com/user/khelstrom/media/StingerDE-80Sch.gif.html

[duck_arse]

if you wired the battery clip backwards, the protection diode will kill the battery and probably burn the board. you should check you are connecting the batt neg to the board neg.

[Paul Marossy]

if you wired the battery clip backwards, the protection diode will kill the battery and probably burn the board. you should check you are connecting the batt neg to the board neg.

+1