My aquaboy dx build- dry signal, no delay mn3005

[jighead81]

I put in a LT1054 and now it's running a steady 15V. Got the BBD's calibrated and it sounds lovely.  Got a new problem now. The rate indicator LED just stays on now, and doesn't pulse, and I don't have any modulation

[thorpy6]

ok, here are the voltages running from a 9v supply:

353 chipe

1=4.58
2=4.58
3=4.55
4=0
5=4.58
6=4.58
7=4.58
8=9v

062 chip

1=floating
2=4-5v float
3=3-5v float
4=0
5=4.58
6=4.58
7=4.58
8=9v

sa571n

1=0.9
2=1.8
3=1.8
4=0.3
5=1.8
6=1.8
7=2.9
8=1.8
9=1.8
10=4.8
11=4.8
12=1.8
13=9.16
14=1.8
15=1.8
16=0.8

MN3005
1=8.98
2=4.5
3=4.6
4=4.6
5=0
6=4.5
7=4.4
8=0.6

MN3101
1=9
2=4.5
3= 0
4=4.5
5=2.9-3.9 float
6=4.9-5.5 float
7=4.1-4.5 float
8=0.6v

[Scruffie]

I put in a LT1054 and now it's running a steady 15V. Got the BBD's calibrated and it sounds lovely.  Got a new problem now. The rate indicator LED just stays on now, and doesn't pulse, and I don't have any modulation

...What were you using before the LT1054?

TL062 voltages, try without the rate indicator LED too.

[Scruffie]

ok, here are the voltages running from a 9v supply:

353 chipe

1=4.58
2=4.58
3=4.55
4=0
5=4.58
6=4.58
7=4.58
8=9v

062 chip

1=floating
2=4-5v float
3=3-5v float
4=0
5=4.58
6=4.58
7=4.58
8=9v

sa571n

1=0.9
2=1.8
3=1.8
4=0.3
5=1.8
6=1.8
7=2.9
8=1.8
9=1.8
10=4.8
11=4.8
12=1.8
13=9.16
14=1.8
15=1.8
16=0.8

MN3005
1=8.98
2=4.5
3=4.6
4=4.6
5=0
6=4.5
7=4.4
8=0.6

MN3101
1=9
2=4.5
3= 0
4=4.5
5=2.9-3.9 float
6=4.9-5.5 float
7=4.1-4.5 float
8=0.6v

Thank you, right, 353 is fine, compander is fine (pin 7 is biased a little low though so you may want to diddle with R13 & 14 like we discussed) TL062 is fine... all looks okay voltage wise.

Now it'll be time to audio probe the circuit and see where the signal is getting to.

[thorpy6]

Cool, audio probed the circuit (which enabled me to bias the mn3005's without a signal getting to them) it was the signal between the com pander and the MN3005 that was weak. I adjusted R13 and 14 to 18k each and the delays rang through clean and clear.......

thank you for your help, really glad this got sorted because its such a great sounding delay.

and to prove my build is complete here are the guts etc:

[thorpy6]

oh and is there any chance the build docs can make it clear r13 and R14 should be socketed 100%? it seems to be quite important..

[jighead81]

Nice job thorpy! 

As far as the TL062 goes.... I was troubleshooting the modulation section last night and removed the 100k from R43 because it looked kinda fishy.  For some reason I replaced it with a 10k.  That's what my problem was.  I put a 100k back in there and now I have modulation!  The only problem I have left is that I get oscillation at the halfway point of the feedback pot, with the trimmer all the way down.  Off to troubleshoot that.  Thanks so much for the help Scruff

[Scruffie]

oh and is there any chance the build docs can make it clear r13 and R14 should be socketed 100%? it seems to be quite important..

Why it has been such an issue i'm not so sure, I question if it's the chip brand but i'd have to see some data to support it.

Some reading of the compander cookbook should make it clearer, I believe it has the biasing equation, it's possible with a different production line the same equation no longer applies.

[thorpy6]

oh and is there any chance the build docs can make it clear r13 and R14 should be socketed 100%? it seems to be quite important..

Why it has been such an issue i'm not so sure, I question if it's the chip brand but i'd have to see some data to support it.

Some reading of the compander cookbook should make it clearer, I believe it has the biasing equation, it's possible with a different production line the same equation no longer applies.

sounds like dry read!! seriously though, thanks for the help. very much appreciated.

[Scruffie]

Nice job thorpy! 

As far as the TL062 goes.... I was troubleshooting the modulation section last night and removed the 100k from R43 because it looked kinda fishy.  For some reason I replaced it with a 10k.  That's what my problem was.  I put a 100k back in there and now I have modulation!  The only problem I have left is that I get oscillation at the halfway point of the feedback pot, with the trimmer all the way down.  Off to troubleshoot that.  Thanks so much for the help Scruff

Ahh 

That one does happen on occasion (I have a feeling it's once again down to compander biasing letting more signal through when biased right and also the increased signal swing of increasing the voltage = more signal hitting the BBD) you can play with R39 (increase) to get it down, or use a 100k feedback trim (T1).

And don't mention it guys  glad to have helped get the pedals fired up.

[GrindCustoms]

I've got all the same symptoms that Thorpy initially had, will give this a try this evening.

Thanks for the help about that Scruffie

[Scruffie]

I've got all the same symptoms that Thorpy initially had, will give this a try this evening.

Thanks for the help about that Scruffie

If it doesn't work, post your full voltages and hopefully we can get if doing something 

[GrindCustoms]

I'm getting 5.6V at pin 7 of 571N, biasing should be half of the supply if i understanded this ok?

[jighead81]

I got 7.3V at pin 7 of NE570 with 47k's in R13 & R14 running 15v.  Is that in the ballpark of where I need to be?

[GrindCustoms]

I've socketed R13/14, now at 4.3V with 9V supply, using MN3005.

All my voltages looks ok compared to those posted by Thorpy, except Pin8 of MN3101 where i'm getting 7.4V opposite to 0.6V, but reading at the build doc it says that the voltage of VGG should be 14/15th of the supply. So it looks like it's in the ball park?

I'm getting the clock frequency at pin 5 and 6 of each MN3005, but when i probe Pin 3 and 4 to bias them, i get some sort of motor boating sound and nothing from either Pin3 and 4 of IC4.