ElectroVibe Mini Not Vibing

[VanWhy]

Okay, I've spent a good amount of time troubleshooting and hit a wall. I get a boosted signal when footswitch is activated but no vibe/chorus effect. And when I switch the toggle to the Vibe setting, the signal turns off. The LED comes on when bypassed and so does the lamp. The lamp also changes when turning the bias and the gain trimmers.

I tried going through the resistor values. Checked orientation on the tantalum caps. Cleaned flux on the switch...

Is this indicative of a wrong/bad component? Maybe someone has something dumb I missed.

 

[Robert]

Does the lamp pulse, or just light solid?

 

[VanWhy]

Does the lamp pulse, or just light solid?

It pulses

 

[Guardians of the analog]

Audio probe it, follow the signal path. We've all been there.

 

[Robert]

OK, so that mostly eliminates the lower board.

Like @Guardians of the analog said, if you have an audio probe check and see what you have on each of the LDRs.

 

[Robert]

I'll try to get some useful docs put together for you ASAP.

 

[VanWhy]

I'll try to get some useful docs put together for you ASAP.

I just got done probing her. It's hard to follow the traces so not completely sure the path without the schematic. No chorus effect anywhere tho. Only thing I noticed with the LDR's is the left and bottom ones had a nice pronounced signal, with possibly a slight pulsing noise. But the right and top LDR's are quite lower volume. Not sure if that means anything. I was worried about those tiny 1uF caps but they all seem to be good. I'm going to go over every resistor value and see if there is something amiss. I hate to bail on this as I've put a lot of work in it.

 

[Robert]

No, don't give up, we'll get it going.

Don't worry about not hearing chorusing, there won't be any chorusing effect until the vibrato is blended back in with the dry signal at R16/R17.

Vibe mode kills the dry signal path, so since you have no sound when in Vibe mode that's indicating that you're losing the wet signal entirely.

If the bottom LDR has a strong signal then the majority of the phase shift stages are passing signal.

Check for audio on the CV3 pad. If you have audio there then there might be a bad connection between the pin headers and toggle switch on the lower board. If you don't have audio on CV3 we need to find out where it's being lost between LDR4 and CV3.

 

[Robert]

I doubt the problem is on the lower board, unless it's a connection issue (or the CV switch is defective), but just for good measure:

 

[VanWhy]

No, don't give up, we'll get it going.

Don't worry about not hearing chorusing, there won't be any chorusing effect until the vibrato is blended back in with the dry signal at R16/R17.

Vibe mode kills the dry signal path, so since you have no sound when in Vibe mode that's indicating that you're losing the wet signal entirely.

If the bottom LDR has a strong signal then the majority of the phase shift stages are passing signal.

Check for audio on the CV3 pad. If you have audio there then there might be a bad connection between the pin headers and toggle switch on the lower board. If you don't have audio on CV3 we need to find out where it's being lost between LDR4 and CV3.

Okay, I probed it and have audio at CV3. And CV1 and CV2. And audio on the top and bottom lugs of the toggle switch.

 

[Robert]

Okay, I probed it and have audio at CV3. And CV1 and CV2. And audio on the top and bottom lugs of the toggle switch.

Check lug 3 of the volume pot in both switch positions.

 

[VanWhy]

Check lug 3 of the volume pot in both switch positions.

Lug 3 of the volume pot I am getting audio in both positions. The up position it's lower volume. The same for lug 2

 

[Robert]

But still no output?

I assume this is out of the enclosure?

Any chance something is making contact where it shouldn't when it's in the enclosure?

 

[VanWhy]

But still no output?

I assume this is out of the enclosure?

Any chance something is making contact where it shouldn't when it's in the enclosure?

Yep, probing done outside of the enclosure. To probe the pots I had to flip the board over and check where the lugs meet the PCB. Same result when inside and outside the enclosure. No effect. Could it be the pin headers? They are a tad sketchy. I could solder wire in place of the headers. I can replace the toggle switch as well if you think that could be a culprit. Not opposed to desoldering.

 

[Robert]

If you have audio on lug 2 of the volume pot you should have output.

What do you have on the OUT pad?

 

[VanWhy]

If you have audio on lug 2 of the volume pot you should have output.

What do you have on the OUT pad?

Here is a video of me probing some things. The LDR's could be suspect?