Current Lover: No Effect

[eldanko]

Ok, I've searched through the other threads on this board but still haven't come up with a solution.  Jumpers are correct, C5 is jumpered... this is an MN3007 version currently running on a 9V supply.  Here's my IC voltages at the moment:

INPUT: 9.5

IC1
1: 4.7
2: 4.7
3: 4.3
4: 0
5: 4.6
6: 4.7
7: 4.7
8: 9.4

IC2
1: 8.8
2: 4.7
3: 5.0
4: 0
5: 0
6: 4.7
7: 6.5
8: 6.5

IC3
1: 9.4
2: 4.7
3: 4.7
4: 4.7
5: 4.7
6: 4.7
7: 4.7
8: 0
9: 4.7
10: 4.7
11: 4.7
12: 4.7
13: 0
14: 4.7
15: 4.7
16: 0

IC4
1: 4.7
2: 4.7
3: 9.0
4: 0
5: 4.7
6: 0
7: 0
8: 0
9: 0
10: 0
11: 0
12: 0
13: 9.4
14: 9.4

IC5
1: 4.7
2: 4.7
3: 4.6
4: 9.4
5: 1.0
6: 1.0
7: 5.2
8: 8.0
9: 4.2
10: Varies
11: 0
12: 4.2
13: 4.2
14: Varies

IC6
1: 0
2: 5.2
3: 2.9
4: 0
5: 9.4
6: 9.4
7: 9.0
8: 9.4

So... what's off?  Should half of IC4 be dead like that?

[madbean]

Look at the schematic to see that those pins on IC4 are grounded. You are good there.

You are getting signal through, just no effect, correct?
Do you have any signal going into pin3 of the MN3007? Any signal coming out of pins 7 or 8?
Have you tried any other values for C18 other than 22pF, such as 15pF or 47pF?
Since is the MN3007 version, have you omitted D4 and D5?

Thanks for posting voltages first. They seem to be good, in general.

[eldanko]

D4 and D5 omitted....

I am NOT getting signal on pin3 of the MN3007.  What does that mean?

UPDATE: I am, actually... but not pins 1 or 7.

[madbean]

I means you are not even getting signal into the BBD. That's good, because it means the BBD may actually be working correctly, but it has no signal to process.

So, you need to trace back and see where your input drops off. Probe pin1 of IC1 and pin7. See if you have output in both of those places.

[eldanko]

Crap.  I measured wrong earlier.  Turns out I do have signal on pin3, but not on the others. 

[eldanko]

I just switched out all of the ICs with spares one at a time... no change.  Still baffled.

[eldanko]

I just socketed C18 and swapped in a 47pF.  Still no dice.

I got my MN3007s from Mojo Musical.  They're reputable, right?

[marmaliser]

Any chance of a board photo.

Can you try running it at 12 or 15v and rebiassing ?  I had a lot of trouble getting my MN3007 PorkBarrell to bias at 9v

[eldanko]

Sure - here ya go.  I will try running it with higher voltage on my lunch break and see if that changes anything.

[eldanko]

Anyone?  The only thing I can come up with is that I might have two bad MN3007s (came from same source).  Any other theories?

[jkokura]

That's probably what you're looking at. Really, if you've used your audio probe and DMM to get to this point and you're coming to that conclusion, that's what you're dealing with.

The only time I'd doubt that is if I knew that the parts I had worked in another pedal already.

Jacob

[eldanko]

Yeah, I was afraid of that.  I do not have a circuit to test these in, sadly.  Over to Small Bear I go...

[eldanko]

Grrrr.

Ok, popped in a brand new MN3007 from Small Bear.  STILL no effect.  I've tried biasing at both 9V and 15V.  I've swapped out every single IC one by one.  I've double checked my soldering.

I can get it to flange intermittently if I tweak the bias and clock knobs carefully and increase the rate a bit... it will sort of pop in and out of flange every couple of seconds, but won't stay there continuously.  I can also hear a clock-like knocking at the extreme of the clock trimmer and a particular setting on the bias.

Any help would be appreciated at this point.

[Scruffie]

Intermittent flanging is flanging, your BBD works and the audio path seems fine.

Which leaves us tracing further down, the 4049 looks fine, as does the 4013 so we're looking at the LFO & Clocking section.

LFO output isn't running right uness you have it stuck in the Filter Matrix mode for those voltages (I suspect you do).
311 is also stuck. Can you take voltages for the 324 & 311 in both modes for me?


What transistor have you used for Q2? And what diode for D1 & 2?

[eldanko]

You're probably right...

Q2 = 2N5087 / D1 = 1n4148 / D2 = 1N4007

Hmm... it appears I've subbed for D1.  Aren't 1n4148 and 1n914 interchangeable?  I have some 1n914s in stock now if it would be worth swapping that out.

Here's voltages:

DPDT Switch "Up" Position:

IC5
1: 4.7
2: 4.7
3: 4.6
4: 9.4
5: 1.5
6: 1.5
7: 2.6
8: 4.3
9: 4.3
10: 4.3
11: 0
12: 4.3
13: 4.2
14: 4.3

IC6
1: 0
2: 2.6
3: 1.7
4: 0
5: 9.4
6: 9.4
7: 6.3
8: 9.4

DPDT Switch "Down" Position:

IC5
1: 4.7
2: 4.7
3: 4.6
4: 9.4
5: 1.0
6: 1.0
7: 4.3
8: 4.3
9: 4.2
10: 4.2
11: 0
12: 4.2
13: 4.1
14: 4.2

IC6
1: 0
2: 4.3
3: 2.6
4: 0
5: 9.4
6: 9.4
7: 7.6
8: 9.4