Ugly face problem

[edo1123]

I've used the vero with the lfo. Here's the problem: after bursting a lm386 (I've put it upside down), I've replaced it and it started "working". I had just oscillations and the led blinking for the lfo. As I saw in the demos, the led should turn on as I play giving the "auto wah" sound. I've used a ldr that is about 300k light and 5m dark. Maybe is something with it, but I don't know because I've got no significant variation of the oscillations as I turn the control back and forth. The only thing's working is the lfo (I guess it's the lower part of the vero, the one with the 4558). Here are some photos (sorry for the messy wiring):
image99.jpg
image666.jpg
The off board wiring should be right otherwise I shouldn't have any sounds at all, but I may be wrong.

[Beaker]

You need to light-proof your LED/LDR for it to work properly. Any daylight falling on the LDR will overpower the LDR and cause it to be "permanently on". You may get a very slight effect as the LED pulses, but it may be barely noticeable.

You can check if it working properly, but putting a carboard box or something like a thick jacket - anything to temporarily block out as much daylight as possible - over the circuit while you are playing, and see if it suddenly springs to life. If it does, it means you have not made a mistake somewhere.

One you have proved it works, you may need to adjust the position and distance of the LDR relative to the LED for best effect. Once you've got that sorted, it's best to light-seal the LED and LDR - wrap them up together with some heat shrink tube and/or electrical insulation tape.

Once it's fitted in the enclosure there's no chance of daylight getting in of course, but don't forget your indicator LED will be putting some of it's light into the enclosure, so you may need to put a piece of black tape across the back of it.

[edo1123]

I was going to try this, but I'm a little confused. Could this be the problem? I mean, I should get some sound from my guitar even if I don't wrap together the led/ldr, shouldn't I? When I turn it on I get no sound from the guitar, just oscillations.

[Beaker]

Ah, you didn't mention that you were getting no guitar sound through the pedal in your first post.

I thought it was basically working, but you were not getting the optical section performing correctly.

You have an error somewhere, so normal debugging rules apply; check your cuts and links, component placement, values and orientation. Check your solder side for bad solder joints and bridges, and check your off board wiring.

Hopefully someone can spot something from your photos.

[edo1123]

Sorry for not mentioning it.. Anyway I've already check all the basic debug list. I'm sure is something with the wires. When I move it I get a volume "boost"  and, after your suggestion, it worked for two seconds. I'll rewire everything. I'll post here if get more trouble..

[edo1123]

Finished the rewiring and wrapped the led/ldr, but it's still the same. I've started to check the continuity of the input and here's the new problem: I think that input should get out the of pin 5 of the 386, but from input to pin 5 there's a resistance of -671k.. I guess that the "-" it's obviously a problem and things get weirder when I touch, with one pin of the multimeter still connected to the input, pin 2 and pin 3.

Touching pin 2 the power supply goes in protection and I clearly hear a pop (surely not a good thing for the power supply), meanwhile at pin 3 (the point where the input should be connected) I  have -671k again.. Maybe it's just the capacitor.

Any ideas on the "-671k"? I've never read something like that on the multimeter.

[Beaker]

If it suddenly works when you press or move something, it is almost certainly a bad solder joint somewhere. Your photos aren't clear enough to see much from. but it looks like you have a large solder bridge across two rows around your top IC1 / LED area.

[edo1123]

It works!!! It was the 9v wire, I put it one row down. Thanks to your suggestion I didn't tear it apart and I make it work :-) . I should change the combination led/ldr or at least change the ldr because oscilations seem to be too high pitched.