Caesar Chorus - Steady Rate LED?

[IPv6Freely]

Having issues with my second Caesar Chorus build. When power is applied, the rate LED does not flash at all. It just stays on solidly.

I've gone over making sure all the parts are in the right way, the joints look good (even reflowed a couple that looked like they may have been an issue), and I'm out of ideas. Here's my board.

Now, there is one important thing to point out. The copper trace that connect Q2, R25 and D101 (the bottom right) was damaged while removing Q2 (I replaced it because I damaged it while removing it also).

This is the connection I'm talking about:

I fixed that by jumpering them together on the bottom of the board. Maybe this is related to my problem, but I don't think it should be. That trace is carrying +9V, by the way, AFAIK based on the schematic.


Oof... I really should have cleaned that flux off...

Anyway - any suggestions on where to even start on this one?

 

[IPv6Freely]

Something doesn't look right, Your Vref at 1C 2.1 only has 2.94 v & elsewhere it is 4.33v which is where it should be at I believe?
Here is a resistor Calculator you can check your Values with.
Click on Bands for 5 Bands:

Resistor Calculator

Resistor Calculator is an App developed by CherryJourney to help the user find the value of a resistor.

resistor.cherryjourney.pt

2.94V for VREF. 4.33V for VREF_2

I don't fully understand why you're sending me a resistor calculator... can you explain?

 

[music6000]

2.94V for VREF. 4.33V for VREF_2

I don't fully understand why you're sending me a resistor calculator... can you explain?

To check that all your resistors are the correct values.
Match the bands on the resistors to the Calculator & confirm your Values are correct.

 

[IPv6Freely]

To check that all your resistors are the correct values.
Match the bands on the resistors to the Calculator & confirm your Values are correct.

Got it... yeah I guess I can do that. It's not that many and I'm very meticulous about making sure they're all oriented the same way.

 

[IPv6Freely]

To check that all your resistors are the correct values.
Match the bands on the resistors to the Calculator & confirm your Values are correct.

Aaaand I’m an idiot.


Not one resistor was wrong… FOUR are wrong.

 

[music6000]

There was a revision recently, The values on the PCB should be the correct values, sometimes the ones in the BOM are incorrect ?????

 

[IPv6Freely]

There was a revision recently, The values on the PCB should be the correct values, sometimes the ones in the BOM are incorrect ?????

Nah, it’s all me. To be fair, they are all various 33 values that were sorted into the wrong bins. 3.3K instead of 330K. 330K instead of 33K

 

[IPv6Freely]

 

[IPv6Freely]

Well that problem is solved... now to figure out why there's no sound. lol

 

[Stickman393]

MOAR OP AMP VOLTAGES!!

 

[music6000]

Nah, it’s all me. To be fair, they are all various 33 values that were sorted into the wrong bins. 3.3K instead of 330K. 330K instead of 33K

33ohm, 330ohm, 3K3, 330K, 1 Band to ruin it all !
That is why I measure every Resistor, Capacitor, Transistor, Diode, LED I put in a PCB & I Bend the legs first in case it damages the component!!!

Can you post the voltages you have on each OP Amp now?
1.......8
2.......7
3.......6
4.......5

 

[IPv6Freely]

MOAR OP AMP VOLTAGES!!

33ohm, 330ohm, 3K3, 330K, 1 Band to ruin it all !
That is why I measure every Resistor, Capacitor, Transistor, Diode, LED I put in a PCB & I Bend the legs first in case it damages the component!!!

Can you post the voltages you have on each OP Amp now?
1.......8
2.......7
3.......6
4.......5

Here's the list with before and after values.

IC1: TL022
1 - 4.319 - cycling 3.5-4.5
2 - 4.339 - 4.27
3 - 4.339 - 3.9-4.5
4 - 0.000 - 0.000
5 - 4.337 - 4.27
6 - 4.357 - 4.29
7 - 4.339 - 3.9-4.5
8 - 8.690 - 8.570

IC2: RC4558
1 - 2.942 - 8.67
2 - 2.954 - 8.63
3 - 2.944 - 8.68
4 - 0.000 - 0.000
5 - 2.946 - 8.69
6 - 2.948 - 8.68
7 - 2.948 - 8.63
8 - 8.76 - 8.69

IC3: V3207D (using MN3207)
1 - 0.000 - 0.000
2 - 8.68 - 4.16
3 - 2.292 - 7.8
4 - 8.12 - 8.0
5 - 8.68 - 8.55
6 - 0.2 - 4.14
7 - 1.1 - 8.08
8 - 1.0 - 8.08

IC4: V3102D
1 - 8.68 - 8.55
2 - 0.1 - 4.138
3 - 0.000 - 0.000
4 - 8.68 - 4.158
5 - 25.0 - 272mV
6 - 8.60 - 8.22
7 - 2.871 - 2.82
8 - 8.11 - 7.99

Q1: 2N5088
C - 2.112 - 7.16
B - 2.593 - 7.47
E - 8.74 - 8.66

Q2: 2N5088
C - 3.65 - 8.51
B - 1.1 - 4.0-4.2
E - 8.66 - 8.51

Q3: 2N5088
C - 2.283 - 7.77
B - 2.831 - 8.29
E - 8.74 - 8.66

Q4: 2N5088
C - 0.000 - 0.000
B - 27.0 - 356mV
E - 8.26 - 7.40

Q5: 2N5088
C - 2.33 - 7.31
B - 2.904 - 7.69
E - 8.72 - 8.66



Of course, I assume some of these values are gonna change depending on the pots and the trimpot settings, but at least we have the real baseline now that we know the components are actually correct... lol.

 

[music6000]

Can you confirm that R26 - 33K is correct - Orange, Orange, Black, Red, Brown !

What's going on with IC2: RC4558 double Voltage readings, something screwy there!

 

[IPv6Freely]

Can you confirm that R26 - 33K is correct - Orange, Orange, Black, Red, Brown !

What's going on with IC2: RC4558 double Voltage readings, something screwy there!

R26 is indeed 33K. It's one of the ones I replaced.

IC2 seems right. VREF is changeable by the trimmer pot. So, turned all the way up its 9V, turned all the way down its 0V. I now have it at 4.5V and will keep it there for troubleshooting because that's about where it needs to be in the end anyway. Therefore, at the moment IC2 is all 4.5V except for pin 4 and pin 8