Zvex mammoth vero clone issues

Started by thebangbangbox, March 16, 2014, 12:55:45 PM

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thebangbangbox

The pedal simply does not work. I have wired it it up without a switch to make one less problem. I can get audio through the pedal but it comes out clean with no fuzz. The only knob that work is the output knob. i have checked my soldering and everything is shiny and all components are in the right spot and I checked them all before going on the board with a multimeter. I have taken a blade in between the tracks. I am really stumped here. Why no fuzz or any modulation of the audio signal?  :icon_evil: :icon_evil: :icon_evil:

http://tagboardeffects.blogspot.com/2011/02/zvex-woolly-mammoth-vero.html This is the layout i used for the pedal.

Batterry is at 7.58 volts
Q1
C =7.20volts
B =6.39volts
E =7.00 volts

Q2
C=7.45volts
B=7.20volts
E=7.02volts

I have used a 5.1k resistor in place of the 4.99k one on the layout.

thebangbangbox

#1
I tested all the pots to and they all are in working order just don't have any effect on the circuit  :icon_rolleyes:

nocentelli

Quote from: thebangbangbox on March 16, 2014, 12:55:45 PM

Batterry is at 7.58 volts

Q1
C =7.20volts
B =6.39volts
E =7.00 volts

Q2
C=7.45volts
B=7.20volts
E=7.02volts

I have used a 5.1k resistor in place of the 4.99k one on the layout.

Q1 emitter is connected directly to ground and should therefore be zero volts, so clearly you have a problem here at the very least.
Quote from: kayceesqueeze on the back and never open it up again

thebangbangbox

Okay I have figured out the grounding issue with Q1 emitter had a over looked bad joint  :icon_rolleyes: This has been aggravating me. Still plays clean no fuzz or any control with the pots. Only pot that works is the output pot.

Battery is 7.58
Q1
C =0.54volts
B =0.00volts
E =0.00 volts

Q2
C=0.44volts
B=0.54volts
E=0.01volts 

What other things should i be looking in this circuit that could cause this fault?? I have reflowed all the joint and checked every path again and all is fine. Im kinda stumped with my limited knowledge with pedal building.... ???

PRR

> all is fine

Apparently not.

First ALL your voltages were high (and your battery is weak). That's a missing ground, and not just one transistor.

Now ALL your voltages are low. Not sure how, but I'd trace from Q2 C to battery +, find the bad joint.
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LucifersTrip

#5
...and the elephant in the room...Q1E & B are basically shorted

edit:


always think outside the box

LaceSensor

Ive built that layout numerous times now and it works fine

problem is at your end

thebangbangbox

^^^ I completely understand that. Like I have said in previous post in this thread I am looking for tips for some help. I know the problem is on my end. Duh. I am just trying to learn what else to look for in my case of trouble and looking for some pointers and such. If I didn't think the layout was right do you think i would have soldered it up to give it a shot at starting this new venture.  :icon_wink:  

mthibeau

Post some clear close up pictures of both sides of your board. That may help...

I have built this layout twice with no problems.

Whenever I have issues with vero, it's usually a bad cut, missing cut, or something misplaced or soldered in backwards.
- MikeT