Byzantium Flanger works for approximately 30 seconds each time I plug the power in.

[squirrelboy]

Yeah, it’s weird. The pedal works fine for approximately 30 seconds each time I unplug and plug the power back in, and then after 30 seconds it seems like the LFO stops oscillating.

Any ideas?

 

[Mcknib]

Oooo I am going to check this. Thanks!

Don't get your hopes up haha

It's just something I would check for a fault like this where it intermittently cuts out

I've came across it twice once on an ehx holy grail and once on a tube pedal I'd built because I didn't heatsink the regulator but obviously the tube heaters draw a lot more current

 

[squirrelboy]

Don't get your hopes up haha

It's just something I would check for a fault like this where it intermittently cuts out

I've came across it twice once on an ehx holy grail and once on a tube pedal I'd built because I didn't heatsink the regulator but obviously the tube heaters draw a lot more current

I just replaced it with 150k and it did not solve the problem. Haha. I did get my hopes up!

 

[Mcknib]

I was talking about checking the regulator IC6 to see if it gets warm or hot with the fact it works for 30 seconds then cuts out if it did heat up the thermal shut down would shut it off automatically

But still don't get your hopes up!

 

[squirrelboy]

As an update, I just also determined that I have the wrong value in for R39. I am going to fix that and then report back.

 

[squirrelboy]

I replaced R39 with the correct value and it did not fix the problem. It sounds great for 30 seconds and then goes static.

 

[PJS]

Working for 30 seconds sounds like either something gradually heating up until it stops, or a capacitor gradually charging up until it is fully charged and that stops the circuit working. Check (carefully) for over-warm components, check capacitor values and orientation, and check to see if some short or similar could be leaving voltage into a cap.

 

[HamishR]

I don't know if anyone told you but when you number the pins on an IC the convention is that you count top left as one, go down that column and then back up the right hand side. So on an 8-pin IC the lowest right hand pin is pin 5 and the top right hand pin is pin 8. It looks from your voltages that you are starting at the top for both sides. I apologise if you already knew this! And worry about your voltages!

 

[squirrelboy]

I don't know if anyone told you but when you number the pins on an IC the convention is that you count top left as one, go down that column and then back up the right hand side. So on an 8-pin IC the lowest right hand pin is pin 5 and the top right hand pin is pin 8. It looks from your voltages that you are starting at the top for both sides. I apologise if you already knew this! And worry about your voltages!

This is one of the few things I did know. Haha

 

[squirrelboy]

UPDATE: I reflowed all the solder points and now the pedal is not even working for 30 seconds. Instead, I get the static filter sound that I would get after 30 seconds before reflowing the solder.

 

[PJS]

Honestly, it may not sound like it, but it may be a good thing. A problem that is there all the time is easier to find and fix than a problem that as erratic.

I think I would first be audio probing to see where the signal dies.

 

[squirrelboy]

UPDATE:

Using the schematic, I built the LFO section of the circuit on a breadboard and patched it into the pedal using an alligator clip. Pedal works perfectly now. So, the problem is definitely with the LFO on the PCB. Now that I know a bit more about LFOs, I am going to see if I can figure out what I did wrong on the PCB.

 

[Giorfida]

UPDATE:

Using the schematic, I built the LFO section of the circuit on a breadboard and patched it into the pedal using an alligator clip. Pedal works perfectly now. So, the problem is definitely with the LFO on the PCB. Now that I know a bit more about LFOs, I am going to see if I can figure out what I did wrong on the PCB.

Good thinking on isolating the problem!

 

[PJS]

That is crazy good troubleshooting

 

[squirrelboy]

UPDATE:

I had some time last night to continue to investigate what I might have done wrong on the PCB. I learned that when the power was on, I was getting continuity between pins 1 and 2 of the TL022.

I checked whether I was getting continuity between pins 1 and 2 of the TL022 on the breadboarded version, and I was NOT.

I looked at the schematic, and I don't think I should be getting continuity between pins 1 and 2 of the TL022:


So, I decided to try to figure out why I was getting continuity on the PCB. I determined that Pin 1 of the TL022 was getting continuity with the anode of C30 AND the anode of C3. Pin 2 was getting continuity only with the anode of C3.

To correct this, I removed C30 and C3 from the PCB and then soldered the cathode legs of 2 33uF capacitors together and then soldered the anode of one of them to Pin 1 and the anode of the other one to Pin 2. Now, I am not getting continuity between pins 1 and 2 of the TL022. However, still no oscillation. So, the investigation continues.

Also, I should probably say that I am kind of just posting all of this for posterity or in case someone else has the same problem and my investigation is useful to them.

The investigation will continue tonight once my 14 month old goes to sleep.

 

[Giorfida]

UPDATE:

I had some time last night to continue to investigate what I might have done wrong on the PCB. I learned that when the power was on, I was getting continuity between pins 1 and 2 of the TL022.

I checked whether I was getting continuity between pins 1 and 2 of the TL022 on the breadboarded version, and I was NOT.

I looked at the schematic, and I don't think I should be getting continuity between pins 1 and 2 of the TL022:
View attachment 70497

So, I decided to try to figure out why I was getting continuity on the PCB. I determined that Pin 1 of the TL022 was getting continuity with the anode of C30 AND the anode of C3. Pin 2 was getting continuity only with the anode of C3.

To correct this, I removed C30 and C3 from the PCB and then soldered the cathode legs of 2 33uF capacitors together and then soldered the anode of one of them to Pin 1 and the anode of the other one to Pin 2. Now, I am not getting continuity between pins 1 and 2 of the TL022. However, still no oscillation. So, the investigation continues.

Also, I should probably say that I am kind of just posting all of this for posterity or in case someone else has the same problem and my investigation is useful to them.

The investigation will continue tonight once my 14 month old goes to sleep.

I like how you are working through this. Thank you for sharing the steps

 

[music6000]

UPDATE:

I had some time last night to continue to investigate what I might have done wrong on the PCB. I learned that when the power was on, I was getting continuity between pins 1 and 2 of the TL022.

I checked whether I was getting continuity between pins 1 and 2 of the TL022 on the breadboarded version, and I was NOT.

I looked at the schematic, and I don't think I should be getting continuity between pins 1 and 2 of the TL022:
View attachment 70497

So, I decided to try to figure out why I was getting continuity on the PCB. I determined that Pin 1 of the TL022 was getting continuity with the anode of C30 AND the anode of C3. Pin 2 was getting continuity only with the anode of C3.

To correct this, I removed C30 and C3 from the PCB and then soldered the cathode legs of 2 33uF capacitors together and then soldered the anode of one of them to Pin 1 and the anode of the other one to Pin 2. Now, I am not getting continuity between pins 1 and 2 of the TL022. However, still no oscillation. So, the investigation continues.

Also, I should probably say that I am kind of just posting all of this for posterity or in case someone else has the same problem and my investigation is useful to them.

The investigation will continue tonight once my 14 month old goes to sleep.

When testing for Continuity, you should not have the Power connected to the circuit or you will get a false reading.
Also the pots should be at approx the middle rotation as sometimes they effect the reading when fully C.C.W

 

[squirrelboy]

When testing for Continuity, you should not have the Power connected to the circuit or you will get a false reading.
Also the pots should be at approx the middle rotation as sometimes they effect the reading when fully C.C.W

Oh shoot. Thank you for the tip!

Still, with test conditions the same on the breadboard (power on), I wasn’t getting continuity between pin 1 and 2. Ultimately, this didn’t end up solving the problem, so maybe I WAS testing incorrectly.

I will keep this in mind for my further testing.

Thanks!