So I have got my Aquaboy DX assembled and have been unsuccessful in trying to bias the delay and get it up and running.
Perhaps I misunderstood something in the build doc, so here's what I did:
Using MN3205, MN3201 - power is regulated 9v
Jumpered R55, R58, R27
Socketed R56 with 470k
Included D1, D2, and D3
Before starting to bias, I was only able to get the frequency on pin 2 or 4 of MN3102 to 7.37 when I adjusted the CLOCK trim to the lowest position. The values below are measured with the CLOCK trim in that poisition and the pots set up as described in the bias section.
I also will attach a picture in case there is something glaring that I am missing.
Thanks so much in advance for helping out!
Q1
C: 9.02
B: 4.126
E: 3.697
Q2
C: 9.02
B: started ~3.5 V and decreased to 0V
E: started ~3.0 V and decreased to 0V
Q3
C: 9.02
B: 3.935
E: 3.356
Q4
C: 9.02
B: 3.35
E: 2.77
IC1
Pin 1: 4.51 Pin 5: 9.02
Pin 2: 4.51 Pin 6: 4.507
Pin 3: 4.50 Pin 7: 4.509
Pin 4: 0 Pin 8: 4.505
IC2
Pin 1: .003 Pin 9: 0
Pin 2: -.302 Pin 10: 0
Pin 3: -.27 Pin 11: 0
Pin 4: 0 Pin 12: 0
Pin 5: .58 Pin 13: 9.02
Pin 6: 2V drops to 0 Pin 14: .30
Pin 7: .53 Pin 15: .25
Pin 8: 0 Pin 16: 0
IC3
Pin 1: 0 Pin 5: 8.05
Pin 2: 4.015 Pin 6: 4.012
Pin 3: 4.096 Pin 7: 3.36
Pin 4: 4.092 Pin 8: 7.58
IC4
Pin 1: 0 Pin 5: 8.05
Pin 2: 4.016 Pin 6: 4.013
Pin 3: 3.962 Pin 7: 3.507
Pin 4: 3.963 Pin 8: 7.58
IC5
Pin 1: 8.06 Pin 5: 4.264
Pin 2: 4.017 Pin 6: 3.789
Pin 3: 0 Pin 7: 3.816
Pin 4: 4.016 Pin 8: 7.51
IC6
Pin 1: 0 - 8 Pin 5: 3.8 – 5.2
Pin 2: 3.9 - 5 Pin 6: 3.8 – 5.2
Pin 3: 3.7 – 5.2 Pin 7: 3.8 – 5.2
Pin 4: 0 Pin 8: 9.02
Your compander voltages look all kinds of wrong...
Totally, I recognize that and looked at the schematic... What would cause that?!?!
Bad solder joint or its busted I think are your 2 options.
Ok, I'll check the joints... Would this be the culprit behind the fact that the frequency is too high on pin 2 and 4 of MN3102, or is that another mystery to troubleshoot as well?!?
I don't think so, what frequency do you get?
QuoteBefore starting to bias, I was only able to get the frequency on pin 2 or 4 of MN3102 to 7.37 when I adjusted the CLOCK trim to the lowest position. The values below are measured with the CLOCK trim in that poisition and the pots set up as described in the bias section.
I think the upper limit I got when I maxed out the CLOCK trim was between 11-12kz
Where was your delay time pot set when taking that? Just to be sure...
C33s value is probably just a bit off due to ceramic tolerance, add an extra small value cap in parallel.
I had things setup according to the bias instructions... I often think I get lost when I get done with actually build and its time to test things out since the bias/calibration instructions seem approximate. These are the "settings" I was using when I made the measurements I provided per the build doc:
· Delay, Mix controls to their center position.
· FDBK at about 1/3 up.
· Rate and Depth controls all the way down.
· Wave switch to the center (off) position.
· BIAS1, BIAS2 and Cancel trimpots to their center position.
I recently got a usb scope as a holiday gift, but I am still figuring it out. I saw on the build doc that it says
"If you do have a scope, you can use it instead of an audio probe to make the proper adjustments to BIAS1, BIAS2, Clock and the Cancel trimpots. When using a scope, set the Cancel trimpot so that the two output waveforms from pins 3 and 4 of IC4 converge."
I have done a fair amount of searching but have been unable to find a tutorial or example of troubleshooting a pedal build w/ a scope for the uninitiated... Please let me know if you know any resources that would help me learn how to use it to diagnose these and other issues.
I will try adding a cap as you suggested tomorrow.
Thanks!
Delay pot in the middle, there's why your clock was so high, that procedure is not a proper set up procedure for the clock.
So, you probably don't need another cap, just get the compander sorted first.
I checked and rechecked the solder joints and the top contacts of the sockets and everything seems fine, so I guess I got a bad IC. Unfortunately, the NE570 isn't one that I have extras around in my stash, so I'll have to order a replacement soon. Is there anything perhaps more "common" (for lack of a better term) that I would be able to sub temporarily w/o damaging the circuit in order to verify that the NE570 IC is indeed the issue?
Thanks again for all your help!
Afraid not, the NE570 (or NE/SA/V571) aren't like a quad opamp or anything, can't just stick something else in there.
Ok, I'll order another and see if things start falling into place when it arrives.