help debugging Man 0' War, bad IC? voltages seem high.

[half_smith]

Well, the day finally came, I got all the IC's in, MN3001's from Small Bear,
MN3005's from DIYGUITARPARTS.AU, and an SA751N from Pedalhacker...
Plugged it all together and... nothing.

*side note, I'm not sure if it's possible to assemble the pedal as described in the build docs, I followed the drilling template exactly on a 1590BB and the DC Jack is blocked by a diode and capacitor. It's not like that in the included photo which appears to be an earlier version. I started a new enclosure in a bigger box, taking the LEDs and Pots off the pcb.

I've started going through the circuit with my audio probe, and found that the signal gets to Pin 6 of the SA751 (NE570), but there's nothing coming out of Pin 7 (and no signal downstream of that point).
I'm hoping someone can offer some help or suggestions in debugging before I order another IC (and hope that's the issue)

should I go to PedalHackers again?
does anyone have a source for another NE570 equivalent?

Here are my IC voltages (Madbean doc values in [...])
Clearly my Q's have crazy high voltage, and PIN7 of IC2 is way high...Does this indicate a specific issue? What is the next step?
- some of the voltages are not printed in the Doc the page seems to get cut off.
https://madbeanpedals.com/projects/_folders/Delay/pdf/ManOWar.pdf

Q1 (2N5088)                                      IC1 (TL072) C   11.85   [11.71]                             1   5.88   [5.84] B   3.68   [5.32]                             2   5.88   [5.86] E   4.8   [5]                             3   5.75   [5.84]                                                         4   0   [0.0]                                                         5   5.75   [5.83] Q2 (2N5088) C   10.4   [11.71]                             6   5.88   [5.85] B   10.73   [2.96]                             7   5.88   [5.85] E   11.85   [2.39]                             8   11.85   [11.71] Q3 (2N5088)                                     IC2 (SA571N - PedalHacker) C   10.97   [11.71]                             1   0.74   [0.88] B   10.5   [6.13]                             2   1.8   [1.77] E   11.84   [5.55]                             3   1.8   [1.77] Q4  (2N5088) C   10.29   [11.71]                             4   0   [0.0] B   10.72   [5.53]                             5   1.19   [1.77] E   11.85   [4.94]                             6   1.17   [1.77] Q5  (2N5088) C   0.5   [0.472]                                7   11.11   [2.97] B   0.5   [0.65]                                8   1.81   [1.77] E   0   [0.0]                                9   1.81   [1.77] Q6  (2N5088) C   0.5   [0.472]                                10   4.03   [3.98] B   0.5   [0.65]                                11   4.03   [3.98] E   0   [0.0]                                12   1.82   [1.77] Q7  (2N5088) C   11.89   [9.4]                               13   11.84   [11.71] B   11.58   [N/A]                               14   1.8   [1.77] E   7.07   [N/A]                               15   1.8   [1.77]                                                        16   0.8      [0.832] IC3 MN3005                                    IC4 MN3101 (Small Bear) 1   11.89   [11.71]                            1   11.23   [11.04] 2   3.4   [5.54]                            2   3.38   [5.54] 3   6.72   [6.04]                            3   0   [0.0] 4   6.33   [N/A]                            4   7.93   [5.51] 5   0   [N/A]                            5   11.16   [10.81] 6   7.91   [N/A]                            6   0.5   [1.7] 7   6.22   [N/A]                            7   0   [varies] 8   0.75   [N/A]                            8   0.75   [0.745] IC5 MN3005                                    IC6 MN3101 (Small Bear) 1   11.84   [11.71]                            1   11.20   [11.11] 2   5.62   [5.58]                            2   5.62   [5.54] 3   4.52   [6.18]                            3   0   [0.0] 4   4.51   [6.16]                            4   5.63   [5.57] 5   0   [0.0]                            5   11.06   [11.04] 6   5.63   [5.58]                            6   0.49   [1.69] 7   5.05   [5.96]                            7   7.04   [9.38] 8   0.74   [0.745]                            8   0.74   [0.755] Huge thanks to anyone who got this far!

[jimilee]

What are you using, voltage wise, to power it? Got any pics front and back and did you reflow everything?


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[half_smith]

I'm using an "AMRENCE POWER SUPPLY" (cheap from Amazon), 12v 300ma

My build is kind of funny because I jammed as many expensive parts in there as I could - for fun?

[half_smith]

I see a few joints in the pics that look sus, so I'm reflowing and cleaning up the board a little more (since taking the pics)

[jimilee]

Lots of solder joints that need solder. They should look like little Hershey kisses. Even after almost 10 years, I still have to go back over mine. I've started doing it along the way, but sometimes I still miss some.


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[half_smith]

Thanks for looking at it. I'm a little sloppy sometimes

[half_smith]

I have a proper Hershey's on each joint, and while this did have an effect on the noises I can get with the audio probe - louder, fuzzier, clicking... Still no good signal past the SA751
There's a fuzzy helicopter kinda sound anywhere past PIN 6 of the SA751

Why is the signal reaching SA751 (PIN 6) and then not coming out PIN7?
(is it a clue that the voltage on this pin is 2x what it should be)?

It's interesting that the build documents say:
"Use an audio probe to probe pin7 of IC3 to verify that you have signal to the input of the first BBD.
If you do not, check pin7 of IC2a and the emitter of Q2 for output. Debug as necessary"

PIN 7 of IC2a (SA751) must be a critical junction, what does it mean that I'm getting right up to it and not out of it?

[half_smith]

I think I just had an "aha!" moment.

I've used 2N5088's for Q1-Q4,. I think it's pinned for 2SC1815, which is a Common Collector E, C, B pinout. The 5088s are Common Base, E, B, C.

How can I use a 5088 in place of a 2SC1815? Is there a trick to cross the legs or something?

[half_smith]

whelp, nevermind that idea. The Build Docs says the board is CBE so my 2N5088s are correct. (*read the footnotes)

Would my overzealous use of non-polar Caps be the problem?
I ordered a NE570 to replace the SA571

[jimilee]

Have you checked all of your resistor values and cap polarities including the np cap?


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[half_smith]

I have checked as many things as many times as I can.
One thing is the PCB has gotten damaged in a few places from desoldering and I've had to make a couple jumpers.
There's a chance there's a bridge somewhere on the top of the PCB I cannot see because it's under components.

What do you mean check the polarity of the np cap?

[jimilee]

Check your polarities and that you used an np cap. Sorry about that.


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[half_smith]

I used the green Bi-Polar caps where ever I had one of the correct value, just playing with the special looking parts in my parts box. Is that ok to do? Do Caps need to be polarized when the schematic calls for it?

Pin7, the output of IC2 (SA571N) is still like double what it should be. How can I diagnose this?

I have found that I do get a blip of good audio on Pin 7 right when I touch the probe to it, then it goes to *click, thrum, click* (and from there throughout the rest of the circuit).

[half_smith]

What components would be responsible for high voltage on Pin 7 and a tiny blip of good sound followed by tick tick tick tick...

The sound is good through the output (C5), Q1 (good voltages and sound), and ok voltages and sound out of Pins 5, 2, and 3 of the SA571, someone on Facebook suggested it could be a "DC biasing" issue, what components are suspect?

Thanks!

[benny_profane]

Are you still getting the out-of-range voltage reading on pin 7? Based on what you've said about desoldering, broken traces, and the need for jumpers, I think that the board itself needs to be verified. Also, do you have any other circuits that use a compander so that you can verify the part?

I'm not sure if the issues I had with my MoW build are happening here--and I'm not convinced that the fixes there are going to help.

(https://www.madbeanpedals.com/forum/index.php?topic=30538.0)