Aquaboy Deluxe troubleshooting - Getting dry but not delay

[Myrkky Nuoli]

Alright then. First time posting here. I just ran through an Aquaboy DX build and this is where I'm at:

I'm using V3205 BBD's, MN3102 clock and NE571 compander. I have omitted the D3 and replaced R58 with a jumper. I used the suggested values for R27, R55 and R56.
In summary, I get dry signal but not delay. So here's the details.

Compander: I'm getting signal from pin 7 but it's very distorted. The output BIAS is around 3V which seems pretty low to me but I fiddled with the R13/R14 voltage divider and raising it didn't really do all that much so I figured I'll come back here and make it sound better as soon as I get my repeats through. Or is it supposed to get boosted here and toned down later on? 'cause the dry signal coming out from the jack is clean. It distorts a little in the LF353 but the compander is definitely what makes it nasty.

I'm getting the same exact sound (CLEARLY more distorted than bypass signal, like a thin a bright overdrive) at the input of BBD 1 and here's where the problem lies. I'm getting only a high pitched squeal at pin 3 of the BBD. I tried swapping them and they both sound the same so I think it's not a faulty chip. Any of the trimmers are not helping. Sooo, where should I start poking?

Some voltages:

IC1 (LF353)

1. 4,61V
2. 4,61V
3. 4,59V
4. 0
5. 4,59V
6. 4,59V
7. 4,61V
8. 9,24V

IC2 - Compander (NE571)

1. 1,27V
2. 1,79V
3. 1,78V
4. 0
5. 1,79V
6. 1,76V
7. 3,02V
8. 1,79V
9. 1,78V
10. 4,71V
12. 4,71V
13. 1,79V
14. 1,78V
15. 1,78V
16. 0,13V

IC3 - BBD1 (V3205

1. 0
2. 4,11V
3. 3,87V
4. 3,91V
5. 8,25V
6. 4,11V
7. 4,47V
8. 7,69V

IC4 - BBD 2 (V3205)

Pretty much the same as BBD1 but the trimmer range leaves a bit to be desired. It's 4,33V when cranked where as BIAS1 goes all the way to 5,7V.

IC5 - Clock (MN3102)

1. 8,25V
2. 4,11V
3. 0
4. 4,11V
5. 3,99V
6. 4,24V
7. 3,82V
8. 7,69V

Q1 (this seems weird 'cause the emitter is higher than base.

C. 9,24V
B. 2,81V
E. 3,35V

Q2

C. 9,24V
B. 2,9V
E. 2,41V

Q3

C. 9,24V
B. 2,92V
E. 2,4V

Q4

C. 9,24V
B. 3,46V
E. 3V


Thanks!

[harpplayer]

Did you get it to work? I am having problems with my. It was working alright, but last time I tried the delayed signal was very weak.

I probed it, and it seems to have a problem on the compander. The signal is clear and strong until the second half of it (pins 14 and 15). But when I try either 10 or 11 (the output), it is very quiet.

Didn´t measure the voltages yet, but will do later today.

Anyone has any idea?

Tks,
André

[harpplayer]

You may want to check the 9v tracing going to pin 13 of the compander. You should be getting 9V there!

[Myrkky Nuoli]

Thanks man! I haven't had a lot of time to troubleshoot this sucker but I'm going to continue any day now. Thanks for the tip! I'm also leaning towards a compander problem. The signal is totally fine until it hits the compander and distorts pretty heavily. Doesn't seem right. I'm gonna trace the voltage path and maybe order new companders to compare.

[guillem3]

Hi, I´m having the exact same issues  using mn3205 bbds, did you manage to sort it out?. I´ve already changed r13/14 to get the appropiate voltages, and I´m running out of ideas. It could be I´ve got the fake ones...