SOLVED Electrovibe - Deadish?

[zachlovescoffee]

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!

 

[zachlovescoffee]

Can you verify these voltages for us?

View attachment 21352

I'm not the best at reading schematics and translating into real life. I've looked at this and the board.

For the +9v it looks like I'm just measuring pin 8 on the LT1054CP. Or am I measuring it at the diode? Or between those two points?Or pin to ground?

For the +18v it looks like I'm measuring one side of the 47R that connects to the 100uF cap. Do I measure between those two points?

For the +15V it looks like I'm measuring pin 5 (V Out) on the LT1054CP. That is measured to ground, yes?

 

[zachlovescoffee]

Okie dokie so I did some measurements based on the above but I'll write out what I did so you can troubleshoot me for stupidity.

Pin 8 of the LT1054CP to ground and go 8.98 vdc
D5 connected to the positive side of the 100uF cap (C11) measured 16.78 vdc
C22, the 100n box cap below the -ve board and 100uF cap it measured 12vdc

I reflowed solder in a few places, namely, the vibe switch and now I am getting a fully LED on the vibe side. But no LED on the speed side. I am also getting vibrato now. Chorus sounds a little weak but it seems to be there.

 

[zachlovescoffee]

Hey ya'll,

I'm at a loss for why this LED on the speed circuit is not working. I have verified continuity and re-flowed all of the solder within a mile of that component. I pulled the LED and tested it on a 3.2v battery and it works fine.

One odd thing last night was that as I was trying to measure the voltage of the LED to ensure it was getting some juice, which btw the way it was only getting ~ 0.450vdc, I was able to get it to light up. To get it to light up I had to have both of the leads of my tester on each leg (anode and cathode) and then one of them had to touch a solder pad somewhere on the board. Then the freaking thing would light up! So, I figured, hey maybe there is a short or something. I reflowed every single bit of solder within 2-3 hops of that component and still, nothing.

I'm at a loss. The pedal seems to be working but the LED when switched on does not work. I've attached some up close photos to see if it stimulates any energy from this crew.

 

[JamieJ]

Can you take a photo of your switch wiring?

The other option is it could be a broken trace. You could try a jumper wire from the power jack +ve into the LEDR which feeds the LED.

 

[zachlovescoffee]

Can you take a photo of your switch wiring?

The other option is it could be a broken trace. You could try a jumper wire from the power jack +ve into the LEDR which feeds the LED.

I'll try the jumper and report back. Here are some photos

 

[fig]

Is this resistor is 47KΩ? (left edge)

Edit: It's the other side, but there are so many 4K7 / 47K s in this build, I was trying to check as many as I could for you.

 

[zachlovescoffee]

View attachment 21504



Is this resistor is 47KΩ? (left edge)

It is a 47k resistor. Though it measured 46.78K. I can't get the bastard back in the pad now that I had to remove it Measured in circuit it was ~15k.

 

[zachlovescoffee]

Can you take a photo of your switch wiring?

The other option is it could be a broken trace. You could try a jumper wire from the power jack +ve into the LEDR which feeds the LED.

To accomplish this is it taking the +ve wire (from the board where it comes in from the DC jack) and running a jumper to which side of the LEDR resistor? The opposite side of the trace? Or the side of the trace that goes to the LED? Or am I totally off here?

 

[zachlovescoffee]

To accomplish this is it taking the +ve wire (from the board where it comes in from the DC jack) and running a jumper to which side of the LEDR resistor? The opposite side of the trace? Or the side of the trace that goes to the LED? Or am I totally off here?

I tried what I laid out above. I soldered a wire to the positive lug of the DC jack and then alligator clip to the side of the resistor connected to the big black line and didn't get anything. Did I do it wrong?

 

[JamieJ]

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.

 

[zachlovescoffee]

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.

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.

 

[JamieJ]

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?

 

[JamieJ]

It could also be worth using some IPA to clean the bird as sometimes solder bridges or bits of wire can get caught in the flux.

 

[zachlovescoffee]

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.

 

[JamieJ]

Is the LED 100% oriented correctly?

 

[fig]

...or even 50%!

 

[zachlovescoffee]

Is the LED 100% oriented correctly?

Yes 100%. Anode is on the A pad and cathode on the K pad.

 

[Big Monk]

Yes 100%. Anode is on the A pad and cathode on the K pad.

What value resistor did you use for LEDR?

 

[zachlovescoffee]

What value resistor did you use for LEDR?

4k7

 

[Big Monk]

4k7

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.