SOLVED Deflector is not Deflecting -- Signal is Defecting

[digitalyeti]

Hey All,

Long time lurker, first time poster. Have been having a blast building pedals during lockdown. It has been a fantastic way to distract myself from what I should be doing, mainly writing my PhD dissertation. In all honesty, I think I enjoy building the pedals more than even playing the guitar.

So the reason for this post. I am building my fifth pedal — haven’t had any issues with my previous builds that some basic troubleshooting could not fix. However, the Deflector is giving me some problems.

Everything assembled easily. I have sound when turned off and sound when turned on. However, when turned on, my signal is the same as when off — in other words the signal is not being changed by the pedal.

I did the usual troubleshooting — switched out all the ICs (thank goodness I socketed them) and double checked all the solder joints and reflowed them to double check everything. Triple checked all my component values and made sure they were the right polarity (stripes down) Still, no go.

Using an audio probe, I am receiving signal at pin 2 of the FV-1, which matches what I should be getting based on the schematic. (Most of the other FV-1 builds from PedalPCB look for signal on pin 1, but according to the schematic I believe that the Deflector is different). I do not have an output signal from pin 28. I do get a faint clicking sound, which is not present in the final output of the pedal at the output jack.

I have continuity between pin 14 of the FV-1 and pin 6 of the EEPROM, as well as pin 15 of the FV-1 and pin 5 of the EEPROM. I have the proper 3.3v going to pin 13 of the FV-1.

When I short the voltage going to pin 13 (by shorting R4) so as to use the internal FV-1 programs, I DO receive a signal at pin 28 of the FV1, but it is not modulated or changed.

This leads me to believe that I might have a bad EEPROM. Could I be missing anything else? I have attached a picture of the front of the board. I would rather not pull it out again and bend the Pots to show the back, but will if you all think it can help.

I have a CH341A USB flasher and can trying flashing an EEPROM if someone can send me the hex or bin file that is correct for the Deflector. Otherwise, I might ask about getting a new EEPROM, unless I am missing something . . .

You all rock, look forward to hearing your thoughts!

 

[phi1]

Can you get chorus / reverb sounds with pin13 grounded? Patch 000 of the internal rom is reverb/slash chorus (check out the fv-1 datasheet), and the deflector runs the fv-1 on patch 000. for this test turn the deflect knob down and see if you can get the chorus and reverb sounds messing w the other knobs. If you’re getting chorus/reverb sounds, then yeah maybe a bad eeprom. You could also verify that pins 16, 17, 18 are all reading 0v.

 

[zgrav]

maybe you could try reading your deflector eeprom and see if you get any data from it. If it turns out to be blank you could at least find another program from to d/l to try (not as a substitute for the right program for your box).

 

[digitalyeti]

Well poop. Okay, I got the EEPROM .bin filed sent to me. After not having luck getting it working on a Mac, I fired up an old PC. Unfortunately, it does not appear the EEPROM is the problem. I can confirm that the file sent to me was the data on the EEPROM I was using. I still flashed a brand new 24LC32A chip with the Deflector .bin and swapped it out. The pedal is working exactly the same.

To the questions above:

- Yes, pins 16, 17, 18 (and 19, 24, and 25) all read 0v. Pins 23 and 26 read 3.3 v. Pins 22, 21, and 20 all have a value that changes as the pots are turned. Heck here is a voltage readout of all the FV-1 pins:

1: 0.4v
2: 1.3v
3: 1.65v
4: 0v
5: 0v
6: 3.3v
7: 0v
8: 3.3v
9: 1.7v
10: 1.5v
11: 0v
12: 0v
13: 3.3v
14: 3.3v
15: 3.3v
16: 0v
17: 0v
18: 0v
19: 0v
20: 1.3v
21: 1.2v
22: 1.75v
23: 3.3v
24: 0v
25: 0v
26: 3.3v
27: 1.7v
28: 1.7v

- I do not receive any signal from Pin 28 UNLESS pin 13 is shorted. However, even when pin 13 is shorted, the signal I receive on does not have any modulation -- NO chorus or reverb effect. You are right, it should have some modulation based on the internal program of the FV-1, shouldn't it?

Any thoughts on what I might be missing? Could I have gotten a bad FV-1? The chip is getting signal and seems to be getting proper voltages, and I am not hearing what I should be hearing at pin 28, which seems like this might be the case?

Any help that can be provided would be appreciated. I would love to find out I am missing something basic and foolish. Thank you for the help that has already been provided.

Shawn

 

[zgrav]

try writing a different program onto your new eeprom and see if you get anything through the FV-1 when it is installed on the board. this seems unlikely to work, but no harm in trying.

also use a wire to short pin 2 to pin 28 and make sure your incoming signal has a clear path out of the board.

 

[digitalyeti]

Hi All,

I do not have a different program to write to the EEPROM. However, considering that I have tried the program with two different eeprom chips, one flashed by me and the other independently sourced chip flashed by PedalPCB, it seems likely this would only measure whether there is a problem with the eeprom program which seems to work for everyone else.

Shorted a wire from pin 2 to pin 28 and no real change. Maybe it is a bit louder? Do not think there is an issue with path from pin 28 to output as I have traced this with an audio probe.

With that said, when I mess with the knobs of the pedal I hear a click sound at pin 1 of the FV-1 using my audio probe. When I adjust the density knob the speed of the click changes. This click sound is also present at pin 28, which should be the output of the FV-1 chip and this click sound is later mixed with the input to generate the pedal's output. In other words, what I hear at output is the input signal mixed with this click sound. The click sound gets louder and softer based on the mix knob. I apologize for not reporting on it earlier -- it is not very loud and (logically) goes away when the mix knob is turned off.

Considering that most builds use pin 1 of the FV-1 as the input, I am wondering if the root of my issue lies here? According to the schematic for the pedal, the input of FV-1 is labeled "FB." I am unfamiliar with this designation. FB is also found in the schematic as feeding the reflect knob. I have tried shorting pin 2 to pin 1 to force a signal into pin 1, but it made no difference.

Can anybody help me identify what FB is? Should I be hearing a click going into pin 1 of the FV-1? Perhaps the answers to these questions might give me some relevant insight.

Regardless of the outcome, I am learning a ton about building pedals by troubleshooting this beast. If I can solve it I will feel like I truly have accomplished something. Thanks in advance!

 

[zgrav]

I built the Deflector without incident, as have others, so there does not seem to be a design problem with the pcb. could be a problem with a bad trace on your pcb, but it seems like you have at least made sure the audio path is OK.

The Deflector is put together differently from most of the other FV-1 boards. The Density control regulates the clock frequency from the 4049, which I would have guessed to be much higher than anything that would cause a clicking sound when you vary the pot. Maybe the FV-1 is not getting a valid clock signal from the cd4049? I could see that stopping the FV-1 from working, so it may be worth double-checking the connections and part values for that part of the board.

It is possible you have a bad FV-1 chip, and you are well on your way to eliminating other causes.

 

[Robert]

Pin 2 is the input for the Deflector.
Pin 1 is a feedback path, you won't have signal on Pin 1 if you don't have an output on Pin 27.

A defective FV-1 isn't impossible, but it's not the most likely problem (and is quite rare).


Can you double check the value of this cap? It should be 2.2nF, but it looks like it could possibly be a 2u2 MLCC.
That would certainly cause a problem.

 

[digitalyeti]

SOLVED!

I cannot believe I missed that capacitor screwup. I triple checked the values, but the 2n2 versus 2u2 got away from me.

I am happy to say, switching that capacitor fixed it and this pedal is a dream.

Thank you so much for all the help -- I was getting very close to abandoning this pedal and moving on to the next build.

You all rock. PedalPCB Administrator -- whoever you are and wherever you are -- you have my thanks and appreciation!

 

[fig]

I was getting very close to abandoning this pedal and moving on to the next build.

Now now....was the possibility of me offering advice that scary?

btw, very nice looking build! Glad it wasn't haunted.