Aquaboy DX No delay, high pitch whine when probing

[mtharper928]

So I have been trying to debug this badboy for the last 3 days and cannot find the problem.  I am using v3205 BBDs, with v3102 clock, and v571 compander.  I tried to audio probe IC3, pin 3,  as stated in the directions, but when I did so the only output was a high pitched whine.  I adjusted BIAS1 and it did nothing.  I then adjusted CLOCK (after starting it half way up) in small increments and again adjusted BIAS1.  This only modified the frequency of the whine, while still not passing any sound from the guitar.  I followed the input, probing along the way, and found the signal working on pin7 of IC2, so I believe the compander is working.  I also have signal on pin7 of IC3, so the BBD is receiving the signal.  I double checked the jumpers and they are in the right position.  I also used the other BBD to make sure the one I was using wasn't trashed.  Out of curiosity I then probed OUT, and got the clean signal with no delay or distortion.  I adjusted BIAS1, CLOCK, and several of the pots, and got no change.  I then took voltages of all the ICs, and they are listed below:

Lf353:
1: 4.65
2:  4.65
3: 4.62
4: 0
5: 4.62
6: 4.64
7: 4.63
8: 9.30

V571:
1: 0.93
2: 1.83
3: 1.83
4: 0
5: 1.84
6: 1.80
7: 2.82
8: 1.84
9: 1.84
10: 5.29
11: 5.29
12: 1.84
13: 9.30
14: 1.83
15: 1.83
16: 0.14

V3205 (BBD 1):
1: 0
2: 4.12
3: 3.84
4: 3.86
5: 8.25
6: 4.11
7: 0.01
8: 7.78

V3205 (BBD 2):
1: 0
2: 4.11
3: 3.88
4: 3.91
5: 8.25
6: 4.11
7: 1.94
8: 7.78

V3102:
1: 8.25
2: 4.11
3: 0
4: 4.11
5: 4.06
6: 4.17
7: 3.79
8: 7.78

TL062: I have no idea what is going on with this.  Besides input and GND, the voltages are all over the place!
1: 0.69-8.51
2: 4.08-5.20
3: 3.81-5.13
4: 0
5: 4.04-5.29
6: 4.06-5.11
7: 4.10-5.05
8: 9.3

I am out of ideas on how to fix this lil beast, and any advice would be greatly appreciated, before I go crazy!

Thanks in advance!

[Scruffie]

The TL062 is the LFO, the voltages are meant to be moving.

You have no Bias voltage on Pin 7 of BBD 1, be sure your trimmer and that pin isn't shorted or cold soldered.

[mtharper928]

You have no Bias voltage on Pin 7 of BBD 1, be sure your trimmer and that pin isn't shorted or cold soldered.

I checked all the solders and connections and touched up a few that I thought might be the culprit.  Right after that I realized that I had the trimmer turned down when I took last voltages, so I re-did them.  Pin7 on BBD1 reads 0.01 when BIAS1 is full CCW, 0.13 with BIAS1 centered, and 1.42 when all the way clockwise.  Still get good signal when audio probing pin7, but pin3 gives nothing but the whine, regardless of BIAS1 setting. 

I also just probed OUTPUT2 (pin10) of the compander and did not get the clean signal, like on OUTPUT1 (pin7).  Not sure if this should be the case, or if this may be the reason that I'm not getting delay, but either way, it's getting frustrating!

[Scruffie]

You have no Bias voltage on Pin 7 of BBD 1, be sure your trimmer and that pin isn't shorted or cold soldered.

I checked all the solders and connections and touched up a few that I thought might be the culprit.  Right after that I realized that I had the trimmer turned down when I took last voltages, so I re-did them.  Pin7 on BBD1 reads 0.01 when BIAS1 is full CCW, 0.13 with BIAS1 centered, and 1.42 when all the way clockwise.  Still get good signal when audio probing pin7, but pin3 gives nothing but the whine, regardless of BIAS1 setting. 

I also just probed OUTPUT2 (pin10) of the compander and did not get the clean signal, like on OUTPUT1 (pin7).  Not sure if this should be the case, or if this may be the reason that I'm not getting delay, but either way, it's getting frustrating!

1.42V on full? That's not right, it's a voltage divider, should be a lot higher, Bias will probably be around 4-6V

Are R19 & 55 the correct values?

The compander wouldn't have any signal on its output if there is no signal coming from the BBD and getting in to it.

[mtharper928]

Yup they seem fine,  R19=82k, and I used the recommended R55=100k (as well as the R27=470k).  It says to lower R18 and R26 if I am having trouble biasing with the trim pots.  How low should these be, or a good starting point to test?   

[Scruffie]

Yup they seem fine,  R19=82k, and I used the recommended R55=100k (as well as the R27=470k).  It says to lower R18 and R26 if I am having trouble biasing with the trim pots.  How low should these be, or a good starting point to test?   

*Shrugs* 47k? Depends what you've got on hand, just stick some sockets in or tap wires to a breadboard.

[mtharper928]

So I gradually reduced R55 down to 1k and got the same results with the high pitched whine on pin3 of BBD1.  I then reduced R18, then R19 in the same fashion and got the same results.  Also even with all the resistors having low values, BIAS1 (which I made sure was the right value) still only gives 1.68V when turned all the way clockwise  Should I just trash the v3205s and start over with another BBD?  I am completely lost here!  

[Scruffie]

So I gradually reduced R55 down to 1k and got the same results with the high pitched whine on pin3 of BBD1.  I then reduced R18, then R19 in the same fashion and got the same results.  Also even with all the resistors having low values, BIAS1 (which I made sure was the right value) still only gives 1.68V when turned all the way clockwise  Should I just trash the v3205s and start over with another BBD?  I am completely lost here!  

Take the BBD out and measure the voltage on pin 7, that should tell you if the BBD is the issue. Ignore the whine, for now, that's just the clock.

That is weird that you can't get higher than that on the trim...

What are your Q2 voltages and your voltages on both sides of R20 and all 3 Pins of Bias 1.

[mtharper928]

Checked pin7 without the BBD and still got the same reading.  On Q2 I got 2.26, 2.26, and 2.82.  On BIAS1 showed 0, 1.68, 1.68 on 1,2,3 respectively.  When checking R20, to my extreme surprise, the voltage on one side was 1.68, but the other side was 8.25!!!  I then noticed that I mistook the orange for red on the resistor, probably from populating that portion of the board way too late at night.  Anyway I am about to replace it with the correct 10k, hoping that this is the culprit.

[Scruffie]

Checked pin7 without the BBD and still got the same reading.  On Q2 I got 2.26, 2.26, and 2.82.  On BIAS1 showed 0, 1.68, 1.68 on 1,2,3 respectively.  When checking R20, to my extreme surprise, the voltage on one side was 1.68, but the other side was 8.25!!!  I then noticed that I mistook the orange for red on the resistor, probably from populating that portion of the board way too late at night.  Anyway I am about to replace it with the correct 10k, hoping that this is the culprit.

easily done.

10k? Should be 4k7 from the schematic i'm looking at.

Your Q2 voltages aren't right either... Q2 should be connected directly to 9V at the collector for a start.

[mtharper928]

You are absolutely right with the 4k7..I gotta stop soldering late at night..still works with the 10k though!  And regardless of Q2's would-be effect in the sound, I'm done tinkering with it for now.  I already love this pedal the way she is!  Thanks A LOT for your help Scruffie, without which I would probably be melting the board right now instead of melting my own face!!   

[Scruffie]

You are absolutely right with the 4k7..I gotta stop soldering late at night..still works with the 10k though!  And regardless of Q2's would-be effect in the sound, I'm done tinkering with it for now.  I already love this pedal the way she is!  Thanks A LOT for your help Scruffie, without which I would probably be melting the board right now instead of melting my own face!!   

Seeing as you gave two 2.26 readings, we'll put that down to a late night mistake on Q2 

Congrats! Glad you like it and that's what the forum's here for