3pdt.com Electric Mistress DIY Flanger kit doesn't affect sound when on

[Mukobi]

Hi,

I bought an Electric Goddess kit (http://www.3pdt.com/products/electric-goddess-flanger) from www.3pdt.com (it's their clone of the EHX Deluxe Electric Mistress), although through a seller on Reverb.com instead of their main website. I assembled it correctly (as much as the instruction book helped; it doesn't have a schematic included) and double checked everything, but when I turn on the pedal it has no effect on my guitar signal. Sound still comes out, but no flanging occurs no matter where the 3 internal trim pots or the 3 main potentiometers are; it sounds just like the true bypass sound.

Could this be the result of a faulty BBD chip, or could it be something else? I don't think I harmed any of the 6 ICs (IC1 is JRC4558, IC2 is MN3207, IC3 is LM324, IC4 is LM311N, IC5 is CD4013B, IC6 is CD4049B) because I only put them in their sockets after soldering the whole board. The LED does go on when the pedal is on, if that helps.

What I've tried so far is reflowing all sketchy solder joints, messing with the 3 internal trim pots and the 3 big external pots, and taking all the chips out and putting them back in, but nothing has changed the problem. In the instruction, they say that T2 regulates the BBD bias at IC2 MN3207 pin 3 which should be 4.9V, but I was only able to get it to about 4.84V by turning that trim pot all the way clockwise.

I'm guessing you will need some voltages too, but what should I measure? I'm pretty new to this and this is a fairly complicated board. http://imgur.com/a/FXPlC Here are some pictures of the schematic, the PCB with and without components, and the switch board, which may help in telling me what to measure.

Thanks!

[Keeb]

A user, Thomeeque, on this forum made an mn3207 flanger based on the electric mistress. The schematic you linked to seems identical to his (i didn't check every component). His thread can be found here: http://www.diystompboxes.com/smfforum/index.php?topic=91981.0. There might be some tips to tune it there, as well as some other debugging stories.

For which voltages to check, use the debugging thread: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[Mukobi]

A user, Thomeeque, on this forum made an mn3207 flanger based on the electric mistress. The schematic you linked to seems identical to his (i didn't check every component). His thread can be found here: http://www.diystompboxes.com/smfforum/index.php?topic=91981.0.

For which voltages to check, use the debugging thread: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Thanks for finding that, it does seem like the same schematic and components, but our 2 PCBs are arranged differently.

So do you basically want me to take voltages of all ICs, transistor, and diode? I'm not sure I can do that right now, but I should be able to find time to test and post that information soon.

[Keeb]

Thanks for finding that, it does seem like the same schematic and components, but our 2 PCBs are arranged differently.

So do you basically want me to take voltages of all ICs, transistor, and diode? I'm not sure I can do that right now, but I should be able to find time to test and post that information soon.

Thomeeque's PCB is single sided (DIY-community friendly!) so it probably doesn't match yours. For the debugging, yes. Voltages from all active components is helpful although quite cumbersome (especially on a more complex circuit like a flanger).

Welcome to the forum by the way! I didn't notice that was your first post.

[Mukobi]

Thanks for finding that, it does seem like the same schematic and components, but our 2 PCBs are arranged differently.

So do you basically want me to take voltages of all ICs, transistor, and diode? I'm not sure I can do that right now, but I should be able to find time to test and post that information soon.

Thomeeque's PCB is single sided (DIY-community friendly!) so it probably doesn't match yours. For the debugging, yes. Voltages from all active components is helpful although quite cumbersome (especially on a more complex circuit like a flanger).

Welcome to the forum by the way! I didn't notice that was your first post.

Thanks! I'll try to get those voltages.

Looking at the schematic, I can't find IC2 MN3207. Is it supposed to be on there, or am I just missing it?

[chuckd666]

It's the larger box shape on the middle top right of the schematic.

[Mukobi]

It's the larger box shape on the middle top right of the schematic.

Thanks, I see it now. Don't know how I missed it...

[chemosis]

i have the same exact problem!! no flange but my clean signal goes through fine. like theres no delay to creae the flange effect.

[Mukobi]

i have the same exact problem!! no flange but my clean signal goes through fine. like theres no delay to creae the flange effect.

Good to hear that this is not unheard of!

I think it might be like you said too. Because flange is based off blending in a slightly delayed signal, I wonder if the BBD IC that is in charge of delay is not working in ours for some reason. Maybe it's just a faulty part and we will have to get a new chip.

I'm taking all of my voltage measurements right now, so hopefully I can get those posted quickly and we can figure out what is going on.

[Mukobi]

I've taken done all the things suggested by the DIYstompboxes.com troubleshooting guide. Here are the results:

What does it do, not do, and sound like: True bypassed the sound is unaffected, but when switched on and powered the sound is still unaffected no matter where any of the 3 knobs or 3 internal trimpots are (it should be flanging) but the light goes on. Notably, without a power source, true bypass is still the true bypass signal but switching the pedal on gives no sound and no light. Also, battery power doesn't work at all (yes, with a cable plugged into the stereo jack) and doesn't give any light or sound when switched on; I was only able to get it light up with a 9V Boss style power supply or a 9V output my BBE Supa Charger isolated power supply.

The above issue and the below voltages were with IC6 as it is oriented in my pictures. The printing on the pcb is rather unclear which side should have the notch of IC6 (as you can see in my pictures below), so I also tried flipping it around. When I did that, it still didn't have any effect on my guitar signal, but a new quiet and constant high pitch whine could be heard that was oscillating in pitch and responded to the potentiometers. It is almost as if that was the flanged frequency, except the pedal was generating that noise and flanging it rather than doing anything to my guitar. Because spontaneous noises generated by a pedal are generally wrong and because the manufacturer's picture of the circuit shows IC6 to be oriented how I originally had it, I flipped it back around.

Name of the circuit = Electric Goddess Flanger (www.3dpt.com clone of EHX Deluxe Electric Mistress)

Source of the project = http://www.3pdt.com/products/electric-goddess-flanger

Pictures of the circuit schematic and my finished (but not working) kit: http://imgur.com/a/FXPlC

Any modifications to the circuit: None

Any parts substitutions: None

Positive ground to negative ground conversion: Not that I have done, and not that I know of in the circuit.

Voltage of the battery I used not connected to anything: -9.14V

Voltage of the isolated power supply 9V output: -9.26V

Voltage at the circuit board at end of the red battery lead with battery plugged in  = -3.2mV (does this mean there is a short on the board?)
Voltage at the center of stereo jack at end of the black battery lead with battery plugged in = 0V

Voltages of all major components using isolated 9v power supply. Multimeter black was attached to negative/ground and red probed the components. T2 Trim set so IC2 MN3207 pin 3 = 4.91V. T1 Trim, T3 Trim, Range, Rate, and Color pots all at noon. Filter/matrix switch is up (which I think is normal flanging mode):

Q1: 2n3904 (NPN)
E = -4.71V
B = -5.29V
C = -9.16V

Q2: 5087 (PNP)
E= -7.95V
B= -7.86V
C= -2.27V

IC1: JRC4558
P1: -4.95V
P2: -4.95V
P3: -2.46V

P4: 0V
P5: -4.47V
P6: -4.93V
P7: -4.91V
P8: -8.93V

IC2: MN3207
P1: 0V
P2: -4.57V
P3: -4.91V
P4: -8.54V
P5: -9.17V
P6: -4.57V
P7: oscillating between -5.55V and -5.65V over about 11 seconds full cycle
P8: oscillating between -5.55V and -5.64V over about 11 seconds full cycle

IC3: LM324
P1: oscillating between -2.87V and -5.23V over about 11 seconds full cycle
P2: oscillating between -4.04V and -4.13V over about 17 (!) seconds full cycle
P3: oscillating between -3.97V and -4.05V over about 11 seconds full cycle
P4: -8.93V
P5: oscillating between -2.40V and -5.75V over about 11 seconds full cycle
P6: oscillating between -3.97V and -4.05V over about 11 seconds full cycle
P7: oscillating between -0.55V and -7.64V over about 11 seconds full cycle
P8: -4.93V
P9: -4.93V
P10: -4.80V
P11: 0V
P12: oscillating between -1.02V and -1.87V over about 11 seconds full cycle
P13: oscillating between -1.05V and -1.89V over about 11 seconds full cycle
P14: oscillating between -1.08V and -2.89V over about 11 seconds full cycle

IC4: LM311N
P1: 0V
P2: oscillating between -1.06V and -2.85V over about 11 seconds full cycle
P3: oscillating between -0.91V and -2.28V over about 11 seconds full cycle
P4: 0V
P5: -9.16V
P6: -9.16V
P7: oscillating between -8.47V and -8.93V over about 11 seconds full cycle
P8: oscillating between -1.08V and -2.95V over about 11 seconds full cycle

IC5: CD4013B
P1: -4.57V
P2: -4.57V
P3: oscillating between -8.46V and -8.94V over about 11 seconds full cycle
P4: 0V
P5: -4.57V
P6: 0V
P7: 0V
P8: 0V
P9: 0V
P10: 0V
P11: 0V
P12: 0V
P13: -9.17V
P14: -9.17V

IC6: CD4049B
P1: -9.17V
P2: oscillating between -4.55V and -4.57V over about 11 seconds full cycle
P3: oscillating between -4.54V and -4.57V over about 11 seconds full cycle
P4: oscillating between -4.56V and -4.57V over about 11 seconds full cycle
P5: oscillating between -4.56V and -4.58V over about 11 seconds full cycle
P6: oscillating between -4.57V and -4.58V over about 11 seconds full cycle
P7: oscillating between -4.56V and -4.58V over about 11 seconds full cycle
P8: 0V
P9: 0V
P10: oscillating between -4.57V and -4.58V over about 11 seconds full cycle
P11: oscillating between -4.57V and -4.58V over about 11 seconds full cycle
P12: 0V
P13: oscillating between -4.56V and -4.58V over about 11 seconds full cycle
P14: oscillating between -4.56V and -4.58V over about 11 seconds full cycle
P15: oscillating between -4.56V and -4.58V over about 11 seconds full cycle
P16: oscillating between -4.56V and -4.58V over about 11 seconds full cycle

D1: 1N4001
A (anode, the non-band end) = -9.17V
K (cathode, the banded end) = -8.76V

D2: 1N4148
A =  oscillating between -0.93V and -2.28V over about 11 seconds full cycle

K =  oscillating between -8.43V and -8.92V over about 11 seconds full cycle

D3: RD10 10V 0.5w Zener
A = 0V
K = -9.17V

[Fender3D]

Troubleshooting a BBD pedal is quite different than with fuzzes or overdrives.
You must be sure BBD actually works.
In order to work BBD needs a clock, a bias voltage @ input, a proper pull-up or pull-down resistor(s) @ output and sometimes a gate voltage (Vgg).
Your BBD's voltages seem ok, now you should check you have a clock @ pins 2 and 6....

If clock is there, then you should check BBD actually passes signal by applying some kind of waveform @ its input, and looking for it @ its output, eventually trimming bias voltage.

Check then report.

[duck_arse]

I don't wish to sound rude, Mukobi, but is your meter actually reading all negative voltages? if it is, you either have a reversed power supply (protection diode says it can't be) or you have the red lead plugged into yr 0V/ground/black jack on the meter, or it has a +/- reverser switch like the old needle meter types.

oh, and NEVER EVER reverse a chip in its socket. if you are at all confused about correct orientation, pull the chip from its socket. put it into some anti-static foam, and leave it there until you have checked the manufacturers data sheet to see where is pin one, and then use your meter to find where the suppy connections are on the pcb. then match the supply pins with the datasheet, AND THEN you will know which way is up.

I understand those bbd chips can get quite expensive. reverse voltage won't make replacing them any cheaper.
[/rude_sounding]

[Mukobi]

I don't wish to sound rude, Mukobi, but is your meter actually reading all negative voltages? if it is, you either have a reversed power supply (protection diode says it can't be) or you have the red lead plugged into yr 0V/ground/black jack on the meter, or it has a +/- reverser switch like the old needle meter types.

oh, and NEVER EVER reverse a chip in its socket. if you are at all confused about correct orientation, pull the chip from its socket. put it into some anti-static foam, and leave it there until you have checked the manufacturers data sheet to see where is pin one, and then use your meter to find where the suppy connections are on the pcb. then match the supply pins with the datasheet, AND THEN you will know which way is up.

I understand those bbd chips can get quite expensive. reverse voltage won't make replacing them any cheaper.
[/rude_sounding]

That's not rude, I appreciate the help. All the negative  voltages in the pedal were recorded with the black multimeter lead on ground and the red lead touching each component to measure it. Also, when I measured the battery by putting the black multimeter lead on negative and the red lead on positive or when I measured my power supply plug by putting the black multimeter lead in the center and the red lead on the outside, my multimeter read negative. This makes me think that the multimeter leads are just plugged into the wrong ports, since the voltages of the circuit and my power supplies on the own were all negative. Either way, the voltage going in was the same polarity as that measured in the circuit, so nothing seems to have been flipping it.

[Mukobi]

Troubleshooting a BBD pedal is quite different than with fuzzes or overdrives.
You must be sure BBD actually works.
In order to work BBD needs a clock, a bias voltage @ input, a proper pull-up or pull-down resistor(s) @ output and sometimes a gate voltage (Vgg).
Your BBD's voltages seem ok, now you should check you have a clock @ pins 2 and 6....

If clock is there, then you should check BBD actually passes signal by applying some kind of waveform @ its input, and looking for it @ its output, eventually trimming bias voltage.

Check then report.

Thanks for the reply! Sorry, I'm rather new at this, but how can I check the clock at pins 2 and 6, and do I need to buy an oscilloscope to apply a waveform to the BDD and see its output?

[Fender3D]

well...

o-scope would be the easy way of course...

you may check clock if your meter can measure frequency and duty cycle (many cheap china multimeters can)
duty cycle should be 50%.

You can inject signal with any noise-maker (ipod, PC, guitar, your favourite index finger...) and listen to it connecting any amplifier.
Search for audio probe...

[Mukobi]

well...

o-scope would be the easy way of course...

you may check clock if your meter can measure frequency and duty cycle (many cheap china multimeters can)
duty cycle should be 50%.

You can inject signal with any noise-maker (ipod, PC, guitar, your favourite index finger...) and listen to it connecting any amplifier.
Search for audio probe...

Thanks for the help. I only have a super cheapo multimeter like this http://www.rocketreviews.com/images4/cen-tech_multimeter.jpg that doesn't have any of the fancy stuff like making noise for continuity or min/max or frequency and duty cycle measuring. Would you recommend I just buy a better one, or might there be some other way to get those readings?

[Fender3D]

https://www.aliexpress.com/item/Professional-True-RMS-Auto-Range-4000-Counts-Resistance-Capacitance-Frequency-Temperature-Victor-Digital-Multimeter-VC97/32545209139.html?spm=2114.01010208.3.56.lxFplA&ws_ab_test=searchweb201556_0,searchweb201602_3_10057_10056_10065_10068_10055_10054_10069_10059_10058_418_10073_10017_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_3&btsid=9e8fcf75-8e2f-4253-ac7c-05bb842d38ec

[slacker]

Here's a couple of quick things you can try that might help pinpoint where the problem is. First remove R16 or just unsolder one end of it and pull it out of the board, this breaks the dry signal path so you'll be able to hear if any signal is getting through the BBD. Try the pedal out and see if you can get any sound by adjusting the trimmers at all. If you can't get any sound, remove the MN3207 and place a piece of wire its socket joining pins 3 and 7, try the pedal out, you should get clean sound because the wire is jumpering where the signal would pass through the BBD. Let us know what results you get.