SOLVED Electrovibe - Deadish?

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zachlovescoffee

Active member
Howdy folks,

I'm at the testing phase of my Electrovibe build and it hasn't been an easy go. I'm not quite certain what's going on with this guy. I have no LEDs but there is power to the board. I have verified +9.25vdc at the power supply, at the board, and from + to the first diode I have continuity. I'm not great at reading schematics so I am not certain how to troubleshoot beyond what I've done so far.

I took some measurements of the LT1054 and I can only assume these are correct. I read them with the black probe "grounded" to the output jack lug.

P1: 2.3vdc
P2: 4.7vdc
P3: 0
P4: -0.005vdc
P5: 8.95vdc
P6: 1.41vdc
P7: 2.54vdc
P8: 0.15vdc

In a *weird* coincidence I somehow touched something on the board with my red probe, while my black probe was touching the ground lug of the output jack and also touching the PCB holder and the LEDs lit up. I'm not 100% certain how I did it and I wasn't really able to reproduce it. So, I figured, hey, maybe I need to actually connect these jacks to the chassis or some kind of ground. So I wired an alligator clip to the output ground lug and clipped it onto my PCB holder. No lights. Wtf.

I went over every single solder I could get to and reflowed and checked for brides. It's a pretty clean piece of work.

Other things I’m not 100% on. LEDs I wired with the anode (+) into the a-pad and cathode (-) into the k-pad. I assume that’s right?

This builds not having a completed build doc isn’t making this any easier.

Any help or troubleshooting steps would be very much appreciated!
 

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You could go from where it goes into the board or from the power jack. Attach the jumper to the opposite side of the tract from the LED. That will make sure you don’t blow the LED. If that works it shows it a problem with the trace. If it doesn’t work it’s probably the switch wiring.
 
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JamieJ said:
You could go from where it goes into the board or from the power jack. Attach the jumper to the opposite side of the tract from the LED. That will make sure you don’t blow the LED. If that works it shows it a problem with the trace. If it doesn’t work it’s probably the switch wiring.
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Is there any chance that the board itself has a manufacturing defect? There are some things on the board that look odd to me that I haven't seen on any of the other boards that are posted on here.
 

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So that is a via, it bridges between different layers of the PCB to help route the signal. It’s how it was designed.

So I’m assuming jumper info to the LEDR didn’t help?

Can we see a picture of the solder sid dog the switch? Can you see any bridges between 3PDT and the underside of the breakout PCB?
 
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I've tried the jumper a few different ways and I actually tried it on both LEDRs just in case. I'm getting nothing to that Speed LED. But the LED is working. See photos.
 

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Big Monk said:
Have you measured the voltage on each side of the resistor? It may be too large.

Side note: Does the effect work? I wouldn’t be spinning my wheels on an LED if the effect itself was still in need of troubleshooting.

I second the advice on trimming and longish nubs leftover and cleaning the flux off.
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Hello! Thanks for all of the great advice.

I have not yet measured the voltage on both sides of the resistor. What I did see is that on the side of the resistor closet to the LED it's only getting ~ 0.549vdc.

How does one measure both sides of the resistor? Point A to ground and Point B to ground? Any point in measuring the voltage across the resistor?

I have sprayed the entire board and switches/breakouts with contact cleaner and I'm letting it dry now.

The pedal DOES appear to work. That is to say, the vibrato part is definitely working. It's not super clear to me that the chorus part is working yet. There is something going on but it's not real big.
 
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I’m still not sure what is going on. Vibrato and chorus work though chorus is a little weak. Most likely because I don’t have the pedal totally sealed from light. Just have some black electrical tape over the sensors.

The LED for speed is barely visible except when I mash my thumb down on the lugs of the back of the switch. Then the LED is more visible and I can even see it pulsating with the pedal. I assume the pulsating bit is part of what’s supposed to happen.

Any idea? Should I try a new switch? Should I wire it directly to the board instead of off the break out board?

I’ll follow this post on wiring directly from the switch to the board: https://forum.pedalpcb.com/threads/electrovibe.7766/post-100218

Pedal sounds great though for the state it’s in. I just want that LED working so I can button this up and get to tweaking gain and bias and playing the dang thing!
 
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zachlovescoffee said:
Now the pedal has no output so I’ll have to do some more investigating. Hah! It’s never ending. Will report back.
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Guitar cable tip was touching the ground pad for itself on the board. I'm using a test box and it's sizing is all janked up. Fixed that bit. Now I have output.

Chorus and Vibrato and sickeningly weak but I haven't had a chance to really play with the trimmers. The DK Pedals video has some good advice so I'll start there to see if I get a better output.
 
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