Current lover MN 3007 Pin 7 & 8 no signal

[Kai]

Hi guys,

I am new to the forum. I am from Germany and developed a pedal building addiction during the last two years. I built around 25 pedals so far.

Even though I succesfully built several madbean pedals (Pork Barrel, Fat Pants, Nautilus and Collosalus), I am stuck with my recent Current Lover project. I searched all forum entries and noticed that most of the people get this damn thing running. I only get a dry signal but no wet signal.

My explanation is that one hears the original signal from the send and return path. Since I didn't here any flanging at all while I tried to bias I decided to try an audio probe. It turned out that I get a signal at the MN 3007 input only (Pin 3) but no output. As I understand, I should get a signal at pin 7 & 8 (output 1 and output 2).   

I triple checked all component values  and there are no obvious solder bridges. The IC itself is working, cause it runs properly within another project.

After having this described problem (no signal at pin 7 & 8 of Mn 3007) for the first time I ordered a second pcb and started from the very beginning. Exactly the same problem. This never happened to me before. Now I am completely helpless.

Is there anybody out there who has an idea how to solve the problem?

I would appreciate your help, guys.

[Scruffie]

Voltages of your chips please.

And make sure you did all the 3007 mods required and not the 3207 version mods.

[madbean]

Kai, first off: I got you email and let me apologize for not getting back to you in a timely manner. I have no good excuse other than it got away from me But, I am glad to see you here on the forum!

Next, as Scruffie said: let's have your voltages on at least the MN3007 to start. Also, please confirm that your jumpers are set according to the build doc (which I'm sure you have done anyway) and that specifically you have done the following:

MN3007 – Omit D4, D5 and C5. Connect the square and round pins of C5 together via a jumper. This does two things: connects pin1 of the MN3007 to VC via a 100R series resistor for (nearly) full voltage operation and connects the VGG pin of the chip to ground. Note that while the Current Lover is intended for 9v operation, you can safely operate it up to 15vDC provided it is well regulated. If you change to a larger supply after biasing it for 9v, you will most likely have to re-bias the effect for the larger supply voltage.

Also, have you tried any other value for C18?

[Kai]

Dear Scruffie, dear Brian,

I am glad to get your sophisticated help.

Anyway, I am pretty sure that everything was exactly done as described in the documents. Since I chose an MN 3007 D4, D5 and C5 have been omitted and C5 was jumpered. The jumpers underneath IC2 (MN3007) are connected from north to south as shown in the document. I also jumpered the two send and return pads. Just take a look at the picture. Maybe I have overseen something important. The PCB is not boxed yet. I tested the circuit with a self-built Beavis Audio breakout box.

Here are the voltages (12V adapter, 0.4 A):

IC1 (JRC4558D):
1 5,86
2 5,86
3 2,91
4 0,00
5 5,31
6 5,84
7 5,82
8 11,69

IC2 (MN3007):
1 11,69
2 5,83
3 4,68
4 0,00
5 0,00
6 5,83
7 8,49
8 8,46

IC3 ((CD4049UBE):
1 11,7
2 5,83
3-7 all 5,87
8 0,00
9-12 all 5,87
13 0,00
14 5,87
15 5,85
16 0,00

IC4 (CD4013BE):
1 5,85
2 5,85
3 11,26
4 0,00
5 5,84
6-11 0,00
12 11,72
13 0,00
14 11,72

IC5 (LM324N):
1 5,84
2 5,84
3 5,32
4 11,71
5 1,33
6 1,35
7 6,18
8 0,6-10,4
9-11 0,00
12 11,72
13 0,00
14 11,72

I appreciate your help, guys! BTW, is there any literature that explains how to understand ICs and their pin voltages?

I am looking forward to hearing from you soon
Kai

[Kai]

Sorry, I forgot to mention voltages for IC 6 (LM311N):
1 0,00
2 5,99
3 5,49
4 0,00
5 11,76
6 11,76
7 11,28
8 11,76

Thanx
Kai

[Kai]

Hi guys,

I am just curious if you have any suggestions how to solve my problem, meanwhile.

Thanks for any help in advance
Kai

[Scruffie]

Your audio path voltages including the 3007 look fine, your 4049 also does but your 4013, 311 & 324 voltages don't look quite right and no working clock, no working flange.

The 324 isn't varying where it should if it's in Flange mode and seems to lack voltage on some pins i'd expect to see it (for instance, pin 9 has nothing where it should) I would suggest you reflow those areas to start off. Might be worth posting a solder side shot of the board.

[Kai]

Dear Scruffie,

now it is weekend again. Time to get back to this issue.

I obviously made a mistake while posting voltages at the first time. I was interrupted by my 5-year-old son and my 8-year-old daughter. I think IC5 is working as it should.

Here's my update for IC4-6. I need your expertise.

IC 4 (CD4014BE):
1 5,82
2 5,82
3 11,11
4 0,00
5 5,84
6-12  0,00
13 11,66
14 11,67

IC 5 (LM324N):
1 5,82
2 5,82
3 5,3
4 11,66
5 1,33
6 1,34
7 5,35
8 0,6-10,4
9 5,06
10 2,9-7,35
11 0,00
12 5,22
13 5,31
14 3,75-6,75

IC6 (LM311N):
1 0,00
2 4,8
3 3,95
4 0,00
5 11,69
6 11,69
7 1,11
8 11,69

I attached a shot of the board's solder side, too. As far as I can see, there is no obvious mistake.

By the way, Brian asked, if I had changed values of C18. Why could this procedure help respectively what would this do to the circuit?

I really appreciate your help. Building effect pedals is an obsession only within a small (worldwide) community.  Thank God for the internet.

Have fun
Kai 

[Scruffie]

Judging by the 324 not moving voltage on Pin 5 i'll assume you're in Matrix Mode, can you flip the switch and measure the voltages on the 311 again... wondering if you VCO isn't work, which can be a common issue with this design.

If they look more like this
LM311
1-0
2-varies
3-varies
4-0
5-11ish
6-11ish
7-varies
8-11ish

Then we'll assume it's working and the problem is your audio path or improper biasing & clock trim set up (they do interact a bit) the rest seems fine.

[Kai]

Dear Scruffie,

I really forgot to switch to the filter mode. Now, I get voltages exactly as you predicted:

IC5 (LM324N):
1 5,87
2 5,87
3 5,33
4 11,74
5-10 varies
11 0,00
12 varies
13 5,34
14 varies

IC6 (LM311N):
1 0,00
2 varies
3 varies
4 0,00
5 11,74
6 11,73
7 9,3-11,2
8 11,74

When I follow biasing instructions in the document nothing happens - no flanging.

There's also one thing I forgot to mention: I need to turn the volume pot fully clockwise to get the right audio level. If one turns it counter clockwise it gets far too quiet - even at "12 o'clock". Is there something wrong with the audio path?

What's should be the next desperate step in my debugging procedure?

Thanks again for your help
Kai

[Scruffie]

Search for and build an audio probe and trace the signal through the pedal.

[Kai]

Dear Scrufffie,

unfortunately, I am back at the very beginning of my debugging process. As I stated in the subject line, the audio signal stops at IC 2 (MN 3007). Actually, there still is a loud signal at pin 3. None of the other pins has an audio signal. Shouldn't there be a signal at either pin 7 or pin 8?

My first guess was, the MN 3007 chip is a fake. I tested the chip in another circuit (FL 301 from Tonepad) and it worked perfectly.  I have absolutely no idea what the reason is.

Doing the audio probe with the bias trimmer I can here a very quiet dry signal. It is possible to set the working range without any effect on MN 3007. The audio signal still stops at pin 3.

As another member said concerning the Current Lover: This seems to be the Moby Dick of all circuits I built so far. What else can I do?

Thanx
Kai
 

[alanp]

I remember swearing at my Current Lover. They tend to be dominatrix rather than bunnies. In my one it was a bridge, don't think I can see any on yours though.

[Kai]

Okay guys, I finally made it. Since it didn't make any sense to me to waste time with my 2nd CL board, I ordered a third one from madbean. I started from the very beginning with brand new resistors, capacitors, diodes and so on. I double-checked all parts before soldering and only kept the old transistors and ICs from my first and second board.

After soldering all parts the beast still had no wet signal (no flangering). I was somehow really dispaired big time. As I reported before I already built around 30 effects of all kind with success.

After a while a magic voice talked to me and said: "If you checked all new parts it has to be one of the old ones." So, I did the audio probe and the signal stopped at pin 7 & 8 again. I put the iron on all solder points around pin 7 & 8 and suddenly I heard a signal on pin 7 & 8. After following the trace to Q1 the signal died again. Finally, I had found had the suspect. I put in a new 2N3904 and ... it finally worked.  This moment was better than ... you know what I mean (don't tell my wife :-)).

Now, I have the unbelievable flanging effect that Andy Summers is famous for. It really sounds like The Police. The only thing is, one can hear a little clock noise in the background. It's a little annoying when there's silence. I have a similar problem with madbean's Collosalus (Eddie Van Halen flanger sound).

How can background noise/ticking be eliminiated in these kind of projects? Any suggestions?

[madbean]

Great to hear you've got it working! It is rewarding to stick with something, even when you want to chuck it...believe me I can empathize.

As far as clock noise- you should be able to dial it out with the clock trimmer. It is set too high. If that doesn't do it, try 47pF for C18 (if it is easy for you to do). Lastly, check that your wires are not crossing paths over the LM311, 4013 and 4049.