Leprechaun

[sndansby]

Hi,

I am having troubles with the Leprechaun build, and I can't bet it to work. The LEDs work and in trouble shooting I have built an audio probe. I bought a Weller 1010 after and have used that to check the solder joints and I think they should all be good. This is my first time using the audio probe and I could not find the schematics for the build so I am flying a little blind. The most puzzling part for me is when testing a resistor some will have one side work, i.e. the right and not the left side. I am not getting any audio from the L78L33 IC. Is there a good tutorial that might show me how to trouble shoot with the audio probe or some resource. I have not been able to find one. I can take pics if that would help.

Thanks

 

[zgrav]

posting clear pictures of each side of the board, and wiring to the jacks and footswitch will help other folks help you.

 

[sndansby]

Here are some pictures of the project.

 

[peccary]

I don't have any troubleshooting tips right now, but the schematic for the Leprechaun can be found here. And you can read how to use your audio probe here. Hopefully that'll help a bit.

 

[zgrav]

With the link to the schematic you can use your audio probe to test the parts of the circuit where audio goes.

First report on the voltages you get on the IC pins using your DMM. Then confirm you have connections to ground where indicated on the schematic. If you cannot read the schematic that well (yet), take a look at the troubleshooting forums here for some ideas and information.

With your audio probe working (meaning you can hear audio when you start by touching the probe to the tip of the input jack), you can start tracking the sound going through the pedal. For pedals that use the FV-1 chip, you can check to see if you have sound at pins 1 and 2, and if you do, see if you have sound on pins 27 and 28. That will help narrow your search to find the issue(s).

 

[chongmagic]

I see a lot of possible cold solder joints, I would definitely reflow the entire board and clean up all the flux residue with IPA. You should be able to just touch some of the joints with your iron and you can get rid of those solder blobs.

 

[sndansby]

Thanks, I will have time to work on it tomorrow and post the results.

 

[Markk]

Not sure if this is your issue, but looks like a bridge here.

 

[BuddytheReow]

Some of the resistors/capacitors are grounded on one side which would explain why you don't have signal on one side of them. I agree with chong, clean the board with some IPA. Be careful not to get it inside the pots. Repost pics when done.

 

[Robert]

Not sure if this is your issue, but looks like a bridge here.

That's a jumper if the expression jack isn't used, no problem there.

 

[sndansby]

This is with the PCB cleaned. When tracing the board I did not get any signal from IC4? Should I replace that or is that normal? Also, from BuddytheReow response I take it that having the signal on one side of a cap or resistor is normal in some instances. Am I interpreting this right? I feel like the newbie that I am and I appreciate all of the help I am getting from all of you.

Thanks

 

[sndansby]

I did go through and touch up the solder joints.

 

[sndansby]

Here is a pic of the acid etched enclosure that I created for this project. That was a huge learning curve as well.

 

[giovanni]

This is with the PCB cleaned. When tracing the board I did not get any signal from IC4? Should I replace that or is that normal? Also, from BuddytheReow response I take it that having the signal on one side of a cap or resistor is normal in some instances. Am I interpreting this right? I feel like the newbie that I am and I appreciate all of the help I am getting from all of you.

Thanks

Components with one lead to ground will read 0V and have no signal. These include: R6,22,28,29,1,9, etc. you’ll see it clearly in the schematic. Same goes for grounded caps.