SOLVED Can some one please tell me what is going on?

[jojofogarty01]

I've got an issue, I'm getting crazy oscillation on a phase 45 PCB I built (watch youtube video). I've tried wiring every which way, cleaning flux residue, switching the IC's, looking for cold joints. I can't seem to figure out what the issue is. The only thing I knowingly did wrong was installing the Zener Diode backward (the cathode was the non-stripe side); but I figured that out and switched it. I don't see that being the issue anyway. Transistors are matched pair. IC's are TL072 (tried tayda batch and amplified parts batch). Please any help would be greatly appreciated.

 

[hamerfan]

Your soldering looks quite clean and nice.
I like to measure all resistors before soldering and compare with the values printed on the board. But thats not easy with that board.

 

[fig]

Are you certain about the polarity of the zener? I'm thinking the stripe is the cathode with most common packages.

 

[EGRENIER]

Are you certain about the polarity of the zener? I'm thinking the stripe is the cathode with most common packages.

I would say one way to check is measure the voltage at R4, anything above 4.7V would prove that the zener is reverse and not doing it's voltage regulation job...

 

[jimilee]

Are you certain about the polarity of the zener? I'm thinking the stripe is the cathode with most common packages.

This

 

[jojofogarty01]

Thanks everyone, indeed the zener was right the first time, so I switched it from right to the wrong polarity. But now when the effect is engaged, I get a dry signal but no phase effect. It's not just an unaffected signal either; its thinner (lacking lowend) Could running voltage through it with the zener reversed have fried any components? I also tried messing with the trim pot to no avail.

 

[Robert]

It sounds like your signal might be passing through the filters stuck at the high end of sweep, it could be that the LFO isn't running.

Does the sound change if you gradually turn the trim pot?

 

[jojofogarty01]

It sounds like your signal might be passing through the filters stuck at the high end of sweep, it could be that the LFO isn't running.

Does the sound change if you gradually turn the trim pot?

No, nothing changes when I adjust the trim pot. I even did so very slowly because some people say these only work well in a very specific position.

 

[jojofogarty01]

So I tried it with the diode reversed (the wrong way) and I can get a sweep and the trim pot and speed knob change the sound but it’s like a high pitched whine that bleeds through on bypass. But when I put the diode in the right way i have the same problem listed above.

 

[jojofogarty01]

SOLVED! The board was laid out for J113 Transistors and I Used 2n5952. Well, after looking at the data sheets for both, the Pinout is reversed for the two (First pic is J113, Second is 2N5952). So I had them in backwards. It explains why I was able to get something when the diode was backwards I guess.