Axis Face Silicon tranny readout

[Greg M.]

Yes, I read the "?" thread and see the point of the original poster, but personally I'm fairly new at this (agonized over a tube screamer and got lucky on Ross comp and Orange Squeezer) and need some guidance.  I've been poring over this Axis Face Silicon (Fuzz Central) for 3 evenings in a row, I've used a couple of different hookup plans, soldered and resoldered, and here I am with no sound at all coming out of this sucker.
Just to give me a kick in the right direction, could some of you previous builders take a look at my transistor readings to see if they look fishy?  Thanks a million.
Q1(2N3904): C=1.5, B=.41, E=0
Q2(PA2369A): C=4.6, B=1.5, E= .86
battery=9.4v

If you can think of anything I may have done wrong, I'd greatly appreciate the heads up.

Thanks,
Greg

ps:  I have learned a great deal from posting and reading posts on this forum.  I do have lots more to learn though (obviously) so thanks for your help and patience.

[brian wenz]

Hello Hello Greg--
    I mentioned this on the "Tonebender" thread yesterday 'cuz this has really kept me confused in the past........have you gone through the circuit and touched-up all the solder connections?  I know you said you resoldered but sometimes just one little cold joint stops everything in it's tracks.  With the readings that you posted you should be getting at least SOME noise.........are all the outputs going to the output and inputs going to the input???    
Just some thoughts...
Brian.

[petemoore]

Thumbprobing yesterday, I found a bad cap I'd used for the input to a Reamer build.
 I use it as an audio injector, thumb noise IMO is handy to have, I just connect it to the signal path, at points throughout the cct. I can usually find where the sound is getting lost this way.
 Or use an Audio sound injector or Audio Probe.
 I'm sure you've re-read the debugging pages///

[Greg M.]

Thanks for the help guys.  And I have re-read the debugging page (actually printed it out and I continue to reread it).  I'm going to have to make an audio probe sooner rather than later.

I think my biggest problem with fx building is when it doesn't work at first, I cross reference myself to death.  Meaning I sit down at the table with the effect, tools, and about five different wiring diagrams and/or schematics and just confuse myself.  I'm referring to offboard stuff, not the circuit board (that would really confuse me).  

I have actually gotten to understand things a little more when the box  doesn't work at first.  When you have to spend some time to fix something, it forces you to learn.  Sounds like life, huh? :wink:

Thanks again,
Greg

[phillip]

Q1(2N3904): C=1.5, B=.41, E=0
Q2(PA2369A): C=4.6, B=1.5, E= .86
battery=9.4v

Your voltages readings look right on the money for Fuzz Face-based circuit like the Axis Face.  I would suspect that there's a bad connection somewhere in the circuit like Brian and Pete mentioned.

It's also worth a shot to make sure that the transistors are oriented the right way.  I can't tell you have many times I've stuck a transistor in a circuit the wrong way around...click it on....nothing happens

If you have a DMM with the "beep" continuity checker, that's also a very useful tool to use to check for shorted components and to make sure that connections are being made.  I also go through and check the resistors to make sure that they're not shorted or open.

Hope this helps some
Phillip

[Doug_H]

;lkj

[brett]

Q1(2N3904): C=1.5, B=.41, E=0

I'm no expert, but I'd be worried that the base voltage is too low.  It needs to be greater than 0.7 to be turned "on".
Also, swap Q1 and Q2.  ie the 2369A should be Q1
So double-check the input cap and 1M grounding resistor.
cheers

[Greg M.]

Thanks for the responses.  I had never used the beep function, but now that I know I have it, I'll sit down with the manual over the weekend and figure out how to use it in debugging.  I'm going to go over the whole thing from bottom to top with a fine tooth comb (I hate that cliche :roll: ).  It's too late at night to test it out, so I'll go at it this weekend.  

I just got a little champ amp clone and I'm dying to see what I can do to it with a fuzz :P .

Thanks all,
Greg

[Phorhas]

Also, swap Q1 and Q2. ie the 2369A should be Q1

The 2369A have less gain so putting it in Q1's spot would pbobably be wiesr from the tone part. I've experamented with 2369a as Q1 and BC109a (i think - no markings) as Q2 with favorable results

[petemoore]

Thanks for the responses.  I had never used the beep function, but now that I know I have it, I'll sit down with the manual over the weekend and figure out how to use it in debugging.  I'm going to go over the whole thing from bottom to top with a fine tooth comb (I hate that cliche :roll: ).  It's too late at night to test it out, so I'll go at it this weekend.  

I just got a little champ amp clone and I'm dying to see what I can do to it with a fuzz .

Thanks all,
Greg

Sorry if this sounds like I'm preaching...good on ya for reading the DMM manual...'when all else fails...read the directions' as my Dad used to say !!! Great recommendation.
  As you're reading the directions, or soon after, think of ways to apply that meter !!! I use 20v range, all resistance ranges and Beep Mode very often.

[Greg M.]

Preach it brother Peete  :lol: .  It's not preaching, it's advice.  And real good advice at that.  I actually read the manual when I bought the meter about a year ago, but my memory is worse even than my soldering skills.  

BTW, what is "thumbprobing"?  I've never heard that before.

Thanks,
Greg

[Greg M.]

Ever get the urge to throw a box that ain't working against the floor of your garage :evil: ?  I'm getting pretty close with this fuzz face.

I've put it together for the 3rd or 4th time and I still don't even get a bypassed signal.  If this were the first pedal I had built, I would think I had a simple hookup problem (which I guess I do actually), but I've built others and didn't have this problem.  This morning I tried another offboard wiring (GGG I think) method that I used on a Ross compressor I built that works beautifully.  Since I had it sitting right there in front of me instead of a sheet of paper, I thought that might help me to get it going.  Guess how well that worked.  

I'm not saying the Fuzz Central wiring layout is no good (it obviously works well and Phillip I'm sure doesn't take my failure or frustration as an insult).  Please don't take it that way as I value your knowledge, assistance, and respect you along with many others here.  It's just that I wanted to try something new since my first attempts fell flat.

I also put together the McCoy Wah/output buffer from Fuzz Central and have no effect there either, but at least I get a bypassed signal  :? .  

To prove this isn't a rant :wink: , I just want to ask a couple of simple questions.  please indulge this frustrated novice.

1.  This one will sound really simple but...do all board designers use the technique of drawing the layout as if you are looking from the copper trace side through to the components?  The transistor pinout is what I'm concerned about here.

2.  If transistors are put in 'backwards', does it ruin them?  I'm using sockets.

3.  The McCoy Wah uses an inductor with 4 leads on it right?  Will a Fulltone (2 lead) inductor work, and does it matter which way it sits?  I told you these were beginner questions, but I'm desperate!

4.  On the AF Si, is the effect output point  #7 (level 3rd lug) or #8 (fuzz 3rd lug)?  I got so used to the GGG layout, I guess I'm spoiled.

Thanks in advance for anyone brave enough to help me sift through this mess I made.

[phillip]

1.  This one will sound really simple but...do all board designers use the technique of drawing the layout as if you are looking from the copper trace side through to the components?  The transistor pinout is what I'm concerned about here.

2.  If transistors are put in 'backwards', does it ruin them?  I'm using sockets.

3.  The McCoy Wah uses an inductor with 4 leads on it right?  Will a Fulltone (2 lead) inductor work, and does it matter which way it sits?  I told you these were beginner questions, but I'm desperate!

4.  On the AF Si, is the effect output point  #7 (level 3rd lug) or #8 (fuzz 3rd lug)?  I got so used to the GGG layout, I guess I'm spoiled.

Thanks in advance for anyone brave enough to help me sift through this mess I made.

I draw the layouts so that it's as if you're looking at the PCB from the component side.

Putting transistors in backwards could ruin them, but I'm betting that it probably wouldn't

I'm not sure if the Fulltone inductor will fit the layout...I drew it with Stuart Castledine's Halo in mind, but the Fulltone inductor should fit.  It does matter which way the inductor sits on the layout.  On the inductor pads you'll notice that the pads are arranged in a square, with the bottom two pads connected by a horizontal trace and the top two pads connected by a horizontal trace.  One lead of the inductor should be connected to one of the two bottom pads, and the other lead of the inductor should be connected to one of the two top pads.  In other words, the two inductor leads shouldn't be directly connected together.

In the Axis Face Silicon the signal output is from the wiper lug (center lug) of the "Level" pot.  You just need to run a wire directly from the center lug of the Level pot to the bypass switch, and from there to the output jack.

Hope this helps some!
Phillip

[Greg M.]

You bet it helps my friend.  I'm going to get this bad boy fuzzing even if I have to work on it for diggidy-two more hours :lol: .

Thanks for the help,
Greg

[b_rogers]

dude, you have got to make the audio probe..take the cord you are using to go in to your amp and sandwich a wire in the threads of the sleeve (ground) and attach it to the ground rail on your board. take another wire and clip it or wrap it around the tip (positive) at the end of that wire put a .1 cap and use its leads to touch around the circuit, like each collector, feedback resistor...maybe omit the drive pot and put a 1k resistor to ground in its place.. then come back here and tell us what you find.