SOLVED Cordyceps Clean Signal Only

[Footsolder]

Not getting any effect from my Cordyceps, passes the clean signal only. The build doc and schematic has not been posted so I'm not sure what the trimmer does, but it doesn't create any effect. I switched out the optocouple several times and reflowed all the joints. Any obvious culprits? Suggestions gratefully accepted!

 

[KR Sound]

Can we see your off board wiring? The jacks and switch.

 

[Footsolder]

Can we see your off board wiring? The jacks and switch.

 

[Diynot]

Did you verify the orientation of the vactrol, specifically the LED side since the LDR is unpolarized.

 

[Footsolder]

Did you verify the orientation of the vactrol, specifically the LED side since the LDR is unpolarized.

I believe so, the board is marked with the LED end and has A and K pads, the vactrol has corresponding long/short LED legs. I also tested the pads with a regular LED and they reacted to the signal from the guitar

 

[Diynot]

I would verify voltage from the charge pump and then audio probe the 565 chip. Here is a pinout diagram I found on the web

Looks like you should get some sort of output on pins 4/6/7, but don’t quote me on that

 

[Footsolder]

I would verify voltage from the charge pump and then audio probe the 565 chip. Here is a pinout diagram I found on the web
View attachment 89537
Looks like you should get some sort of output on pins 4/6/7, but don’t quote me on that

1044:
9.17
5.22
0.00
-3.84
-9.00
4.21
5.67
9.17

565:
8.31
0.38
0.36
8.47
8.47
9.04
9.04

8.94
8.36
9.11
0.20 (varies)
0.20 (varies)
0.00
0.00

 

[Footsolder]

Anybody have an opinion on these voltages? I'm confused as to what the charge pump is doing, assuming it is delivering -9V wouldnt that show up on the 565? I followed the values on the silkscreen as seen on this image posted elsewhere:

 

[giovanni]

This is a tough one. Your solder joints all look great. Not sure what to make of the voltages without the schematic. I also don’t know how the 565 works. The charge pump values seem reasonable but again it’s hard to tell if there is a problem without the schematic.

@Robert do you have the schematic handy?

 

[Diynot]

With an 8.6v source the 1044 voltages match mine close enough. However, presuming your voltages readings on the 565 are pin 1-14 measured/listed counter clockwise, you are reading way hotter than mine. pin 1 on mine is -5.5, 4/5 are 2.4, 6/7 are 4.4v, 10 is 5.9. I audio probed my 565 and get strong signal on pin 4 and modulated signal on 6/7. Audio probe that bad boy and see if you are getting anything out of the chip. Suspect it might be borked. Verify that all your component values are correct based on that picture of the unpopulated board

 

[Footsolder]

With an 8.6v source the 1044 voltages match mine close enough. However, presuming your voltages readings on the 565 are pin 1-14 measured/listed counter clockwise, you are reading way hotter than mine. pin 1 on mine is -5.5, 4/5 are 2.4, 6/7 are 4.4v, 10 is 5.9. I audio probed my 565 and get strong signal on pin 4 and modulated signal on 6/7. Audio probe that bad boy and see if you are getting anything out of the chip. Suspect it might be borked. Verify that all your component values are correct based on that picture of the unpopulated board

Checked all the values and replaced a resistor that was measuring weird. The audio probe did not get a thing from any pins on the 565 (including 4, 6 & 7) except a very weak dry signal on pin 3. Strong signals elsewhere, especially around the opamps, but all uneffected. Does it seem likely I have a bad 565?

 

[Diynot]

That would be my suspicion anyways, but for the sake of due diligence, try reflowing your solder joints and make sure there are no whisker bridges anywhere

 

[Footsolder]

That would be my suspicion anyways, but for the sake of due diligence, try reflowing your solder joints and make sure there are no whisker bridges anywhere

Did the reflow and whisker check. Guess I will get another chip from pedalpcb and hope it is the solution. Thanks for the suggestions!

 

[Stickman393]

Found this online as part of the "mold spore" schematic:



It's definitely incomplete, but it could help you with audio probing the thing.

 

[Diynot]

To be on the side of caution, recheck everything one (maybe 2) more time(s) before dropping the new chip in so as to avoid potentially damaging a second chip. I say that because my 1st troubleshooting thread was an Abyss that took me looking over the components way too many times to finally figure out that I had mixed up 4.7k and 47k resistors.

 

[Footsolder]

UPDATE - the new LM565 arrived and unfortunately it did not fix the issue, still no effect.

I think it is maybe a power issue as the 1044 has +9V on pin 1 and -9V on pin 5, meanwhile the 565 has +9V on pin 10 and also +8.30V on pin 1, same with the empty socket. Where has the -9V supply gone?

It's tricky without a schematic but are there pads i could check for continuity? The partial Craig Anderton schem above is helpful but I wonder if the issue might lie with the connections and parts around the 1044. Any more suggestions very much appreciated!

 

[Footsolder]

Anyone have access to the schematic or thoughts on the lack of -9V? I tried another 1044 but voltages are the same...

 

[Robert]

https://docs.pedalpcb.com/schematic/Schematic-Cordyceps.png

 

[Footsolder]

Ok, I think I fixed it. After following the schem there seemed to be a continuity issue between the 1044 and the 565. I ended up putting a jumper between pin 5 on the 1044 and the 390R resistor connected to pin 1 on the 565 which finally measured a negative voltage. Being an ugly ring mod it is hard to say if it's working perfectly but it is definitely ring modding. I found I had to dime the trimmer to kill bleedthrough from the carrier frequency but, hey, it worked.

 

[Stickman393]

Yeah, that clean blend is a necessary part of the circuit.

I ended up throwing an expression port on mine that takes the range pot out of commission. This one's big draw for me is that ugly screeching you get from playing with that parameter.

Love it.