Current Lover needs lovin' (w/ pics and voltages)

[LateCentury]

Brian, thanks for the info. I was totally doing it wrong. I completely misunderstood how it works.

I'm going to go over my solder joints again and melt down the ones that look a little off and see if that does anything first. I think Ive been using solder that has a lower melting point and doesn't always bond when I think it is.

[BrianS]

If  Scruffie is saying your problem is around R9/10 that's where I would go first.  He's a guru with this stuff.

Don't fret over hooking it up wrong.  Even after I figured out how to use one I did the same thing a couple of times.  I have a Harbinger I built up a year ago, it was a no go and I set it in the does not work box until the other day.  Couldn't get the LFO led to go.  To make this short I had a transistor turned backwards.  This was after I changed a cap, resistor and trannie around led.  These things happen to everyone.  And to be honest most of the problems I've encountered have been easy fixes and you just go  what a DA. LOL. 

[LateCentury]

Ok.  Let's see if you are hooking it up correctly.  Your signal is going to the in jack of the effect (guitar, signal generator, etc...).  The probe phone jack is hooked into your amp and grounded to something.  There is nothing hooked up to the out jack of the effect.  The end of your probe acts as your out jack now, so to say. Not trying to insult your intelligence here so plse dont think that. 

If you want, take the cover off of one of your pedals that's works, hook it up as above, get a signal going through and probe around the board.  That will give you an idea of what you should be hearing. 

That's why I asked if you were getting sound up to C15. If you have no sound at R1 you will have no sound at C15.  So let's determine if you're getting signal to the board when you turn it on.  Thats the beauty of the probe.  If you can follow the signal path off the schematic you can quickly figure out where it stops and that normally will be where your problem is.

So i hooked it up like this and probed nearly the entire board. The only thing I got was humming and louder humming when I touched solder joints. Another wierd thing that was happening was that I had it originally hooked through the effects loop on my amp. I noticed when I had the pedal clicked off, it made a faint flanging signal like if it was turned on. My LEDs are lighting up so there is no mistake whether it is off or on.

At this point I'm tempted to disconnect the optional FX out-inputs and hook it up the regular way to see if that makes any difference.

Also, I have to point out that T1 is not a Bourns 3362P timmer like the others. It is a 10k though. Would that matter at all?

[BrianS]

The trimmer isn't going to make a difference as long as the legs (1,2,3) are soldered to the right pads.

You need to pull everything out and post a picture of the bottom of the board.  You may have a solder bridge that someone can see.  I wired mine up stock and it's working. 

So with your probe and the effect turned on did you have sound at the in jack (not hum), then the 3pdt, then at in In of the board or not?  Normally, if you have bypass sound and no sound when turned on, the first thing I always check for is a ground problem.  And it could certainly be in your wiring of the other jacks. 

Don't give up.  I really hate troubleshooting these things because I'm not IMO good at it.  That's why I have builds that sit in a box over a year old and I just don't want to bother with them.  This is all a good learning experience and sooner or later you will get the pedal going.

[LateCentury]

Thanks Brian. The help is much appreciated. For the time being, here is the bottom of the board.

[BrianS]

I don't see any solder bridges but on some pads the solder looks a little thin.  I would go back and reflow all your joints. Scruffie said your voltages indicated something around R9/10.  Your resistors are right so it's not the wrong value. 

When you have the pedal turned on are you getting sound at the in jack, the 3pdt and board in with your probe?  I'm not trying to be a butthead by continuing to ask this question. 

I myself would at this point take anything extra off of the board and see if you can get it to go with stock wiring. It just takes one more piece out of the equation.

[LateCentury]

Alright, I got the audio probe working like it should. Makes sense now. I disconnected the fx loop and wired it the normal way. Getting clean bypass. Power LED comes on and rate LFO flashing faster and slower with the rate pot.

When switched on, I get audio at R1-6, then R8-10, C1-4, IC pin 1,2 & 7 and bias pins 2 and 3. Other than that, R26 makes a ticking noise and everything else is just crackling and popping. R10 is a lot more faint of a signal but it's there.

[Scruffie]

You need to find out why there is no voltage on pin 3 of the 3007 in your readings.

Look at the schematic, voltage connects to R10, is divided by the bias pot and sent through R9 to pin 3, unless you have the bias pot set completely to the ground side you should have voltage on pin 3, without it the BBD can't work.

I don't know if you bought your 3007 through a reputable supplier, but, if you got it off ebay, I would consider removing it from the socket (using ESD precautions) and probing the voltage at pin 3 then to see if the chip its self is shorting it to ground.

[BrianS]

Glad you got the probe figured out. 

You've got Scruffies interest in this now and he's 9000 times smarter than I am about this stuff.  I will continue to follow because I learn from this also. 

[LateCentury]

I don't know if you bought your 3007 through a reputable supplier, but, if you got it off ebay, I would consider removing it from the socket (using ESD precautions) and probing the voltage at pin 3 then to see if the chip its self is shorting it to ground.

I bought the MN3007 from Smallbear last May. Do you mean probing socket 3 with an audio probe or volt meter?

[Scruffie]

Okay, hopefully it's good then but still, you need to see voltage on pin 3 so yes, probe the pin with your volt meter again with chip in and out and try to work out why voltage is not getting from R10 to pin 3 of the 3007.

[LateCentury]

I took readings with and without the 3007 in. Very different readings this time:

Without:
4.5
.19
1.69
Starts at about 4, then decreases gradually til it hits about .1
4.23
4.23
.21
4.39

With:
4.36
.17
1.92
Starts at about 3, then decreases gradually til it hits about .1
1.12
1.24
4.53

Then, I tried it again and got even different readings:
9.02
4.47
2.16
Starts at about 3, then decreases gradually til it hits about .1
3
3
4.45
.03

[Scruffie]

Right, I don't know what's going on there but the last set of readings you gave are correct but you've just taken the pin numbers in the wrong order.

Did you follow Brian's advice to reflow your joints? I agree with him that they look like they could do with it and that might explain your shifting readings.

[LateCentury]

I reflowed all the joints and got the exact same result.

At what point do I start replacing parts to troubleshoot? If I'm losing audio at R10, do I consider replacing that? Or is it highly unlikely that a resistor is bad?

Thanks a ton for all your help, btw

[Scruffie]

Sorry, I should have said before, your bias voltage is too low, have you tried fiddling with the trimmer? And if yes, what's the highest voltage you get on pin 3 of the 3007.