Aion Redschift / Madbean Kezuroukai24 - selfmade pcb - issues

Started by tuckster, March 29, 2025, 05:15:58 PM

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tuckster

Hi guys,
I made a pcb for a phaser based on Whetstone/Redshift/Kezuroukai24 and of course it is not working.
https://aionfx.com/app/files/docs/redshift_documentation.pdf
https://madbeanpedals.com/projects/_folders/FilterMod/pdf/Kezuroukai24.pdf
My schematic is attached. It's the Aion Redshift with a reduced rate selection a bit like Madbeans but not exactly.

Issues:
- VB is too low, 2.55V should be 3.58V according to the resistors and input voltage
- no modulation noticable
- signal comming out of the LM13700 is very low in volume

When I remove the LM13700 VB drops to 1.99V. Also when I leave them in and remove Q6 & Q7 then VB also drops.
I desoldered parts I added parts, still the same result. It must be some really small stupid error I made...
There is no connection from VB to any other pad (continuity tester).
The pads have been resoldered to avoid bridges between pads. I do that everytime but did it again.
The LFO (with it's controls) is working, I can see it on my oscilloscope.

You might notice the missing trimmer. I accidentally killed it with my soldering iron. No impact on VB. I already installed a new one.
The volume pot is supposed to look like this because the pins are mirrored...
The socket of U3 is also soldered in the wrong direction but the IC was correctly inserted.

The first thing that I need to take care of is VB.

I compared the voltages mentioned in Madbeans pdf to mine. Any hint, why VB is so low?

My OneSpot 9.47V / MB OneSpot 9.42V
9.18V Input PCB (PCB is connected on PedalPCB Protoboard)

VA 8.95V / Aion VA / MB VC 9.17V -> no VA in MB pcb
VC 8.87V / Aion VC / MB VC 9.17V
VB 2.55V / Aion VB / MB VB 4.54V


2n5088            q1            q1           
c38.968.55
b22.454.26
e12.163.95

2n5087            q2            q2           
c32.15-02.177.58 -> mine starts at ~2.2 tden down to 2.15
b28.968.55
e18.959.17

2n7000            q3            q3           
d34.667.43
g22.263.49
s10.8251.69

2n5087            q4            q5           
c35.7 - 7.3~6.5
b25.0 - 7.36.5
e15.6 - 7.36.8

2n5087            q5            q4           
c35.0 - 7.36.5
b24.8 - 7.3varies
e15.6 - 7.36.8

2n5088            q6            q6           
c38.879.16
b22.3-2.5varies
e11.78-1.91.79

2n5088            q7            q7           
c34.9-7.3varies
b21.78-1.91.79
e11.22-1.37~1.2

u1 LM13700

My pins            Voltage            MB pins            voltage           
11.22-1.3316~1.2
20.72-
32.56144.63
42.55134.45
53.7125.46
6-060
73.7105.66
82.5694.53
92.5684.53
103.775.65
11+8.9119.18
123.755.65
132.5644.54
142.5534.54
150.715-
161.22-1.331~1.2

u2 LM13700

My pins            Voltage            MB pins            voltage           
11.22-1.3316~1.2
20.94-0.992-
32.55144.63
42.44134.54
50.38-0.46125.67
6-0.75-0.8460
70.35-0.43105.66
80.6594.53
91.084.53
101.37-1.4275.65
11+8.9119.18
121.44-1.5055.65
132.544.45
142.5534.45
150.92-0.9815-
161.21-1.321~1.2

u3 LM13700

My pins            Voltage            MB pins            voltage           
11.016~1.2
21.2-1.7
34.9-7.314~6.5
45.0-7.213~6.5
52.2-2.4712~2.3
6-60
70.1
81.8
9
10
11+8.9119.18
12
13
14
15
16













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tuckster

Solved, two not unconnected ground pads. No error message in Kicad...
A continuity tester on ALL pads would have solved it faster... :-)
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