Easy Vibe Debugging

[oldrocker]

What jumps out on the layout.    Check that the square pad above c8 isn't touching the trace below it.  And even though you've checked it that c10 is oriented correct.

[Bruce_W]

What jumps out on the layout.    Check that the square pad above c8 isn't touching the trace below it.  And even though you've checked it that c10 is oriented correct.

Checked and those are good. Could you tell me looking at this layout if LED's 1,2,3 and 4 have the positive side on the right?

[R.G.]

Checked and those are good. Could you tell me looking at this layout if LED's 1,2,3 and 4 have the positive side on the right?

Yes.

[R.G.]

You see the jumper to the right of IC1?

Measure that voltage to ground, which is found at the bushing of the input jack. If that voltage isn't between 3 and 4 V, it's not going to work correctly. That's the voltage that sets the operating point where the opamps can amplify signal.

When that is correct, Then all the opamp pins 1,2,3,5,6, and 7 - with the exceptions of pins 1, 2,3 of IC2 and IC3 - must be sitting at that same voltage plus or minus a small fraction of a volt or it's not going to work correctly. The exceptions in IC2 and IC3 are because those two sections create the sweeping LFO voltages, so they must be wiggling around.

This is all irrespective of the LEDs and LDRs.

[Bruce_W]

You see the jumper to the right of IC1?

Measure that voltage to ground, which is found at the bushing of the input jack. If that voltage isn't between 3 and 4 V, it's not going to work correctly. That's the voltage that sets the operating point where the opamps can amplify signal.

When that is correct, Then all the opamp pins 1,2,3,5,6, and 7 - with the exceptions of pins 1, 2,3 of IC2 and IC3 - must be sitting at that same voltage plus or minus a small fraction of a volt or it's not going to work correctly. The exceptions in IC2 and IC3 are because those two sections create the sweeping LFO voltages, so they must be wiggling around.

This is all irrespective of the LEDs and LDRs.

I get 2.5v there. My bsttery has died a little. It is 8.8v now. Where should the - side of the battery be? I have it to the sleeve of the jack on the right, the output i think. Not sure why it changed but now it says 1.1v.

[R.G.]

Check with your meter - are all the places which should connect to ground actually shorted together?

[Bruce_W]

Well I turned it on today and  all of the LED's lit up. Then while I had my amp on standby waiting to try it out (about 5 min) they went out.  I unplugged the battery and waited a little bit then when I plugged the battery back in both bias LED's lit up but then one goes out quickly and the one closer to the edge of the board stays on a little
  while longer. I was going to etch a new board from the original layout and start over but it seems like its close to working. Thanks

[oldrocker]

Blah.

[R.G.]

You probably have some soldering or wiring issues which make it intermittent, from that description.

[Bruce_W]

You probably have some soldering or wiring issues which make it intermittent, from that description.

Well I thought I took care of all that but I had to listen to your advice. I used an Exacto knife between any close connections and sure enough all the LED's light up and the 2 bias LED's stay solid. You are a genius!  So when I first tested it I used my MM using the continuity  setting that beeps. Is it possible that even though it didn't beep it was still connected enough to mess it up?  Now the LED's are supposed to blink right? They stay solid, but I really appreciate all the help and I'm  learning a lot at least. Thanks

[R.G.]

Well I thought I took care of all that but I had to listen to your advice. I used an Exacto knife between any close connections and sure enough all the LED's light up and the 2 bias LED's stay solid.

Hey! Good progress!

You are a genius! 

No, I just have a lot of scars. 

So when I first tested it I used my MM using the continuity  setting that beeps. Is it possible that even though it didn't beep it was still connected enough to mess it up?  Now the LED's are supposed to blink right? They stay solid

Yes, they should go on and off. From what you've already found, suspect more short circuits to the LED traces, and to the traces in and around pins 1, 2, and 3 of IC2 and 3. On the meter, sometimes a little dirt, oil, or leftover solder flux can keep them from making contact. Sometimes sharpening them to a needle point helps break through, as does pressing a bit and rotating the point into the trace. The possibility of bad contacts is always with us.

but I really appreciate all the help and I'm  learning a lot at least.

That's the spirit!

[Bruce_W]

Well I thought I took care of all that but I had to listen to your advice. I used an Exacto knife between any close connections and sure enough all the LED's light up and the 2 bias LED's stay solid.

Hey! Good progress!

You are a genius! 

No, I just have a lot of scars. 

So when I first tested it I used my MM using the continuity  setting that beeps. Is it possible that even though it didn't beep it was still connected enough to mess it up?  Now the LED's are supposed to blink right? They stay solid

Yes, they should go on and off. From what you've already found, suspect more short circuits to the LED traces, and to the traces in and around pins 1, 2, and 3 of IC2 and 3. On the meter, sometimes a little dirt, oil, or leftover solder flux can keep them from making contact. Sometimes sharpening them to a needle point helps break through, as does pressing a bit and rotating the point into the trace. The possibility of bad contacts is always with us.

but I really appreciate all the help and I'm  learning a lot at least.

That's the spirit!

Continued as you said and all is fine except chorus doesn't seem to work. Vibe does though. Like I said, thanks for all the help. Now I think I am going to build a Neovibe.

[oldrocker]

Good job finding some problems.  Trust me.  You want to get it phasing.  That's the best part.  For me getting a pedal fully fuctioning before moving on to the next is much more satisifying.  You're gaining on it don't stop now.