Tonepad Corral - Debug

[marlo830]

I recently finished populating my etched pcb of FP's CE2 clone. My guitar's signal actually passes through but it's more of a buffer right now than a chorus. When the pedal is first plugged in it produces the Chorus sound we all know but after that it becomes a clean signal. Any clues? I've checked the my soldering and checked for bridges, none so far. I don't have extra MN3101s and MN3007s with me as they are pricey.
Here are my voltages:
IC-4 -- MN3101:
1: 9.01  8: .60
2: 4.63  7: 3.07
3: 0      6: 7.8
4: 4.68  5: .3

IC-3 -- MN3007:
1: 9       8: 4.87
2: 4.68   7: 4.87
3: 5.07   6: 4.62
4: .68     5: 0

IC-2 -- TL022:
1: 2.67 - 6.13  8: 9
2: 4.5              7: 3.5 - 5
3: 3.45 - 5      6: 4.53
4: 0                 5: 4.53

IC-1 -- 4558:
1: 6.93  8: 9
2: 6      7: 6.93
3: 6.93  6: 6.93
4: 0      5: 6.93

[bluebunny]

You should check pin 4 on the TL022 - it should be 0V.

[marlo830]

I doubled checked if pin 4 was 0, and yes pin 4 is at 0v. Not sure why I wrote 4.63v on my notebook last night, my bad! Corrected the post now. Thanks!

[Slowpoke101]

Lift one leg of R21, This will get rid of the clean (dry ) audio.
Apply power, set both the depth and range pots to mid-range then play a note on your guitar (or connect a signal source of some type to the input ).
Slowly adjust VR3 until you hear something going through the effect (hopefully you will hear something ).
If you do hear a clear signal ( but wobbled by the depth and rate settings ) keep playing with VR3 until the signal "sounds the best" to you. Setting the bias without test equipment can be a bit hit and miss.
If you do not hear anything at all then things get more fun.

Your voltages look OK but for pin 3 of the MN3007. It's a bit high but adjusting VR3 (which is the bias adjustment) should bring it down. Let us know how you go.

[marlo830]

Lifted the leg of R21 twice now. Adjusted the 10k trimpot, 0-25% turn has no signal. A bit further from that it's all distortion. Beyond the distortion is more of a clean signal. The signal isn't affected by the Depth and Range pots.

[Slowpoke101]

Lifted the leg of R21 twice now. Adjusted the 10k trimpot, 0-25% turn has no signal. A bit further from that it's all distortion. Beyond the distortion is more of a clean signal. The signal isn't affected by the Depth and Range pots.

OK, when you adjusted VR3 past the distortion area and into the "clean" signal area, did you find that if you kept turning VR3 the distortion would return again. The correct adjustment point is midway between the two distortion points. If this is so, reconnect R21 and see if you now have the chorus effect.

Make sure that R27 and R28 are both 4k7 and that VR3 is a 10K trimpot. Also make sure that C18 is a 47uF (16V minimum ) electrolytic and is installed correctly.

[marlo830]

Found the sweet spot for VR3, apparently I also made a similar mistake to a dude who posted a few years back... One of my Resistor had a solder bridge, specifically R31 and R30. Thanks for the help though! Pretty hard to trace if you had a stressful day at college