Electrovibe issues

[diezelmonster666]

Hey guys,
I am currently building my first Electrovibe and I have got all together. The result is a bit frustrating, since:
- In Chorus I only get a really low volume, non-effect sound (unity gain mod is applied)
- In Vibrato I get no sound at all
- The lamp is pulsating well, so no issues here
- Bypass works
- Some of the transistors have weird values when I measure them. Most are running at 12V, but some are at 9V (Q10), 7.9V (Q6), 2.2V (Q5), and even 1,9V (Q15)

Any possible troubleshooting from someone who has successfully built that board? I am happy to provide images and voltage readings. My soldering skills are pretty good, since I actually do that for a living (on non-music PCBs )

Thanks in advance!

 

[Synchrony Pedalworks]

The gurus would likely want pictures. It helps double check parts, etc.

If my memory is right, one recurring and simple problem has been uninsulated pots (especially the dual gang pot) shorting the underlying PCB.

 

[diezelmonster666]

The gurus would likely want pictures. It helps double check parts, etc.

If my memory is right, one recurring and simple problem has been uninsulated pots (especially the dual gang pot) shorting the underlying PCB.

Thanks for your reply. I will check on the dual pots and get some images together.

 

[diezelmonster666]

Ok, I have insulated the dual pots and the result is that now I don't have any sound when activating the circuit. Bypass works great, bulb works great and I have swapped Q6 because I suspected it might be faulty. Any ideas anyone?

 

[PunchySunshine]

View attachment 46652

Ok, I have insulated the dual pots and the result is that now I don't have any sound when activating the circuit. Bypass works great, bulb works great and I have swapped Q6 because I suspected it might be faulty. Any ideas anyone?

I'd double check those board joints on the toggle switch connection

 

[Mcknib]

One of the 'usual' problems with this circuit is mixing up your 4K7s and 47Ks which is fairly easy to do

It's difficult to make out the multiplier bands on your resistors R55 for example you can't really see if that's yellow purple black red brown as it should be 47K or yellow purple black brown brown 4K7

 

[diezelmonster666]

One of the 'usual' problems with this circuit is mixing up your 4K7s and 47Ks which is fairly easy to do

It's difficult to make out the multiplier bands on your resistors R55 for example you can't really see if that's yellow purple black red brown as it should be 47K or yellow purple black brown brown 4K7

Thanks for your reply and suggestions. I have double checked the values on a resistors just now and they match up. The only exception is the 3k3, which I had to replace with a combination of 1k8 & 1k5 since I was out of 3k3 resistors.

 

[PunchySunshine]

Thanks for your reply and suggestions. I have double checked the values on a resistors just now and they match up. The only exception is the 3k3, which I had to replace with a combination of 1k8 & 1k5 since I was out of 3k3 resistors.

Did you use pot condoms on those speed pots too? Have you pulled it out and double checked those pots aren't shorting somewhere on the backside?

 

[diezelmonster666]

Did you use pot condoms on those speed pots too? Have you pulled it out and double checked those pots aren't shorting somewhere on the backside?

Yes, they are on all pots. The pots don't touch the PCB at all. I am not sure what I can do anymore, other than checking all solder joints.

 

[PunchySunshine]

Yes, they are on all pots. The pots don't touch the PCB at all. I am not sure what I can do anymore, other than checking all solder joints.

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