Axis fuzz clone help

[brudy92]

Hello, I'm a newby stuck on my rullywow return fuzz build. So far the bypass works but when I click it on no sound. I'm running a 9v battery right to the rullywow switch pcb for testing. My question is what should be my next step for diagnostics? I'm pretty bummed its not working this only my second build any help would be appreciated. I have some pictures if anyone would like to see them

[patrick398]

Pictures will be useful to help people (not necessarily me) figure out what the problem might be. When i first started building chances were that someone could look at a pic and tell me what the issue was.

Pictures of the component side of the board(s) and also solder side.

If you have a multi-meter volt readings at certain points will also be very helpful. Check out the 'debugging' thread, provide the relevant information and some clever so and so will help as best they can

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[brudy92]

Thanks for the advice im going to try some of these things tonight

[brudy92]

Here are a few images of my project and the schematic. I highlighted in yellow where I'm not seeing any voltage.

[Pedal love]

Here are a few images of my project and the schematic. I highlighted in yellow where I'm not seeing any voltage.

The potentiometer on the output should be a 47k not a 2.2k.

Sent from my SM-S327VL using Tapatalk

[Pedal love]

Here are a few images of my project and the schematic. I highlighted in yellow where I'm not seeing any voltage.

The potentiometer on the output should be a 47k not a 2.2k.

Sent from my SM-S327VL using Tapatalk

However, I have used between 25k - 1meg.

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[thermionix]

2N3906 is a PNP.

[brudy92]

2N3906 is a PNP.

Is it possible my wiring to the switch and jacks are just wrong then?

[patrick398]

Do you have an audio probe? easy enough to build if not but then you can just follow the signal path and see where your signal dies

[antonis]

Thermionix is trying to tell you that 2N3906 is a P-N-P bjt and should not be used for Q1 (probably is a typo on schematic..)

If you have indeed used a 2N3906 for Q1, it will not work properly..!!
(despite their indentical pin-out or, to be more accurate, presicely due to it..) 

P.S.
Most of your highlighted yellow points with "no voltage" should indeed exhibit 0V..
(i.e. all items connected to GND...) 

you can just follow the signal path and see where your signal dies

I'm pretty sure that signal dies on Q1 Collector..
(which actually is Emitter in case of use 2N3906..)

[Fancy Lime]

Nope, 2N3906 PNP is the correct BJT to use as Q1 in an Axis Fuzz, it's just the symbol in the schematic that is wrong. But if they made that mistake when printing the materials, who knows if the orientation of the PNP is correct. You have installed it according to plan but the plan may be wrong, I can't tell from the materials. Check the resistance between the Emitter of Q1 and the bottom of R6. The value should be that of R6. Q1 Emitter to top of R6 should be no resistance. If it is not, the transistor is probably installed backwards. once you are at it, try the same for the Emitter of Q2 and the bottom of R8 (= value of R8) and top of R8 (no resistance).

The yellow points should indeed all be at 0V DC to ground. That assumes that the 0V end of the resistors that only have one of those is the one that goes to ground. We cannot see that from the materials you posted because it does not show the copper traces on the board.

Your switch and jack wiring may or may not be to blame. Try to draw exactly how you did that and let's have a look together.

Cheers,
Andy 

[brudy92]

Nope, 2N3906 PNP is the correct BJT to use as Q1 in an Axis Fuzz, it's just the symbol in the schematic that is wrong. But if they made that mistake when printing the materials, who knows if the orientation of the PNP is correct. You have installed it according to plan but the plan may be wrong, I can't tell from the materials. Check the resistance between the Emitter of Q1 and the bottom of R6. The value should be that of R6. Q1 Emitter to top of R6 should be no resistance. If it is not, the transistor is probably installed backwards. once you are at it, try the same for the Emitter of Q2 and the bottom of R8 (= value of R8) and top of R8 (no resistance).

The yellow points should indeed all be at 0V DC to ground. That assumes that the 0V end of the resistors that only have one of those is the one that goes to ground. We cannot see that from the materials you posted because it does not show the copper traces on the board.

Your switch and jack wiring may or may not be to blame. Try to draw exactly how you did that and let's have a look together.

Cheers,
Andy

Hello Andy,

Thanks for your help. I will try testing for the resistance when I get home from work. Shouldn't I be receiving some sound when this is on? I have nothing, not even a buzz. Meanwhile here is a photo of how I wired it. I will be using outlet power when its done. 9v for testing.



Also if it helps here are the materials:





I believe it was c7 that I changed to an electrolytic cap. Not sure if this is right but it didn't look like a film when there on the pcb.

[rutabaga bob]

On the schematic, the diagram of Q1 is an NPN, even though the name shows a PNP.  Pop a 2N3904 in there.  The name is wrong.

[brudy92]

On the schematic, the diagram of Q1 is an NPN, even though the name shows a PNP.  Pop a 2N3904 in there.  The name is wrong.

Would this explain why it makes no sound at all. I'm confused here because I'm being told its is and is not right

[brudy92]

Do you have an audio probe? easy enough to build if not but then you can just follow the signal path and see where your signal dies

I do not have one but I am considering making one, this is driving me nuts

[MaxPower]

Both should be npn.

[thermionix]

Nope, 2N3906 PNP is the correct BJT to use as Q1 in an Axis Fuzz, it's just the symbol in the schematic that is wrong.
Andy

This is what I thought.  They've got V+ going to the emitter of Q1.  I thought it would need to be PNP to work in this setup, but TBH it's a little over my head.

But with multiple obvious errors on the schematic, who knows how much else is wrong.

[Pedal love]

Nope, 2N3906 PNP is the correct BJT to use as Q1 in an Axis Fuzz, it's just the symbol in the schematic that is wrong.
Andy

This is what I thought.  They've got V+ going to the emitter of Q1.  I thought it would need to be PNP to work in this setup, but TBH it's a little over my head.

But with multiple obvious errors on the schematic, who knows how much else is wrong.

You're schematic is good except all of your signal out is going to ground. 2k pot to out is wrong.

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[MaxPower]

Ha. Very sneaky. The way the schematic is drawn threw me for a loop. Gave it a quick glance and saw the collector of Q1 going towards the top and assumed it connected to the +9V. Upon closer inspection it does indeed call for a PNP transistor for Q1.

Sorry for my error adding to the confusion.

[Pedal love]

Q1 transistor is marked with the arrow going out > Its actually right except for the arrow direction should go in <  I have been through things like this myself. A lot of people here have helped me.

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