short circuit

[guitarboy]

hi. i´ve tried to build the little angel chorus, together with a slapback delay and reverb. But now i have a big problem. the reverb is sounding great. but wenn I solder the chorus in, there´s a short circuit. whem I lay the + of the circuit tester, to the minus of the battery clip, there´s nothing. but when i do the - of the tester, to the + of the clip,  the light flashes up. so it is a short circuit. i think this has something to do, with a diode. but I´ve tried several things. I dont get it. Thanks for your help .

[Jopn]

Any chance you can post some photos?  If you have a short, it's usually that something is touching something it isn't supposed to.  Without photos, we've got as good of a chance find your short as you've got figuring out where I left my car keys.  I swear they were in my pocket, but I checked and they're not...

[guitarboy]

no, this short is caused on the ic I think. when I try the NE 5523 out, there´s no short. but when I change the IC it´s just the same. on the PCB is no wrong connection for sure.

[dexxyy]

Just because you take the ic out and there`s no short doesn`t mean the ic is the culprit. When you take out the ic your circuit is not complete hence no short, the fact this happens with more than one ic also points to there being a problem elsewhere. Post the voltages of all ic pins also voltages of 78l05 and 2n3904.

guitarboy wrote

 on the PCB is no wrong connection for sure.

Oh the number of times I`ve been sure, only to find I have missed something.

[Jopn]

Off board wiring is probably most likely.  

The idea that there might be a short in the IC itself is very unlikely.  Even after building dozens of pedals I still get a short in either my board from a solder bridge, something offboard touching, or a missed cut in the vero.  

Despite this, if you are certain that it's the IC that's the problem, then the only solution would be to swap the IC.

When you get tired of swapping ICs, post up some photos.

[guitarboy]

http://tagboardeffects.blogspot.de/2012/03/ersatz-verben-psuedo-reverb-by.html


these are from my verb padal. like the chorus, it tries to sound. but now it´s silent. and the same problem with the short from minus to plus. but not in the other direction.




pt2399                                              l78l05        

pin 1   3,8  mv                                    in : 6,19     out : 4,70
2         2,30
3        0
4        0
 5       1,41
6        2,14
7       0,65
8       0,68
9       2,27
10      2,27
11      2,27
12      2,27
13      2,27
14      2,27
15      2,27
16      2,27