Simple Woolly Mammoth clone refuses to cooperate

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Simple Woolly Mammoth clone refuses to cooperate

Postby ElSpeakoDelSpanisho » 19 Jan 2014, 21:25

I'm using the Tagboard Effects layout for this, and I've run into a bit of a snag...

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I've substituted a 4.7K resistor in place of the 4K99 the original layout recommends. Everything else is built to spec.

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I've built and re-built this pedal so many times that I'll try ANYTHING at this point to get it to work. Thanks for reading!

Edit: Wow, I completely forgot to say what the problem is in the first place! I get no signal whatsoever when the switch is pressed on, but I get a fine, clear signal when it's turned off/bypassed. The only way I can get noise out of it when engaged is by pressing the input and output cable tips with my fingers- literally- and even then all I get is a loud, fuzzy beep noise.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby tonyharker » 19 Jan 2014, 21:52

You've probably got the transistors the wrong way round. Mine are the other way up.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby ElSpeakoDelSpanisho » 20 Jan 2014, 04:12

Changing the orientation of the transistors has made some interesting results: I still don't get a signal when engaged- all I hear is a feedback-y buzz noise- but the Output and EQ knobs change the volume and EQ of the buzz.

Is it possible I'm just powering this incorrectly? My DC adapters are center-pin negative, like Boss pedals and such; if I plugged a pin-positive wallwart into this pedal, could I get some sound, or would it make my board explode or something?
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby dwmorrin » 21 Jan 2014, 04:04

Can't quite see what's going on with your power jack. Almost looks like it only has 1 wire connected to it. There are 2 wires, right? What's the voltage measurement right at the power jack? Red and black probes right at the jack.
Does the LED light up?
What transistors are you using? The device number will tell you the pinout so you can be sure about orientation.
Can you provide voltage measurements from ground to each transistor terminal?

If you plug the power in backwards it won't work, unless you've made some pretty big errors! Won't explode either. If something were to break, you'd have another thing to fix, so at least wait until you actually get to play through it a couple times before you purposely try to destroy it. :D

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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby ElSpeakoDelSpanisho » 21 Jan 2014, 04:51

Just an update, I tried re-wiring the 3PDT with this layout just for giggles to see if it would change anything, and as I expected, it didn't.

Can't quite see what's going on with your power jack. Almost looks like it only has 1 wire connected to it. There are 2 wires, right?


You're correct, I only have one wire going to the DC jack, the red 9V coming from the board. I don't think there are two wires for this schematic, since I'm not using a battery clip in this pedal. As for the voltage of the jack, I'll get back to you tomorrow, since it's getting late here.

Does the LED light up?


It's not actually wired up right now, lol, forgot to mention that too. I didn't want to add the extra hassle of keeping that part in place on the cardboard.

What transistors are you using? The device number will tell you the pinout so you can be sure about orientation.


They're 2N3904 transistors. I'll flip the transistors back around again and measure the voltages to ground tomorrow for you.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby Nocentelli » 21 Jan 2014, 06:58

IvIarks's layout show the correct orientation for 2N3904 so put the transistors in as they are shown.

Every circuit needs two power wires, positive and negative. In pedals, we tend to connect the power supply negative to the guitar and amp's ground (i.e. input and output shield) as well as the circuit ground/negative.
brownwhopping wrote:How can I learn by reading threads an making circuits, when some day I can see a lawsuit or somebody beat me in the face for that?
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby bato001 » 21 Jan 2014, 13:11

Take a box cutter, a razor blade or penknife and clean between the traces on your vero board. Vero is unforgiving of solder bridges and flux fried between the traces.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby dwmorrin » 21 Jan 2014, 13:17

You're correct, I only have one wire going to the DC jack, the red 9V coming from the board

There's at least one problem for you. You need 2 wires coming from the dc jack. You also need the negative from the power supply, and this gets connected to ground. It may not be explicitly mentioned, but this is how power supplies work. Remember, it's a circuit, a loop. Your circuit is OFF at the moment.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby ElSpeakoDelSpanisho » 21 Jan 2014, 22:47

Alright, after adding a wire from DC negative to ground and thoroughly knifing the vero traces, still nothing.

Image

BUT, I do have some measurements (all in volts):

DC Jack-9.10

Q1 C- .66
B- 0
E- 0
Q2- C- .02
B- .66
E- 0
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby dwmorrin » 22 Jan 2014, 13:21

Q1 C- .66
B- 0
E- 0
Q2- C- .02
B- .66
E- 0

Q2 emitter needs voltage there, and that will supply Q1 base.
Check for short to 0V on Q2 emitter. Low resistance check with meter, no eyeballing or cutting.
Check that the transistor legs are really connected to circuit board through socket. Low resistance check from leg on lop to solder on bottom.

If it's not a short to 0V there, then you may still have power wired up wrong.
Q2's collector is a bit low even for fully saturated (0.02V), so it looks like a error. Check the collector resistor, 20k, that it is indeed delivering 9V. If so, then Q2 is fully on/saturated if the 20k is dropping 9.08V (9.1V supply voltage).

Since you've got sockets, this is a good test: pull out the transistors, plug in the circuit, and check for +9 at both collector sockets, and Q2 base. You should have +9 at all 3 of those points with the transistors pulled.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby mattlee0037 » 26 Jan 2014, 04:50

Yeah I would think the Collector voltage would be higher than that... check for a bad solder joint right off the 9v supply on the 51k resistor.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby ElSpeakoDelSpanisho » 26 Jan 2014, 05:58

While fiddling with the board, I was actually able to get some sound for a split second while jiggling the Q2 transistor. I figured it might have a loose solder joint on the socket holding it in place, so I desoldered the socket and soldered the transistor directly to the board, but even after that I got no sound with the effect engaged.

After having done that, I realized my solder work on this board is so shoddy that I can't justify spending any more time trying to fix it when I have plenty of spare parts that I can use to make a new board, so I've scrapped this current board. I'm sorry if I've wasted your time, I truly appreciate all of your help! If my next build has issues I will be sure to keep you all updated, with measurements, pictures, and all.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby bato001 » 26 Jan 2014, 06:14

ElSpeakoDelSpanisho wrote:While fiddling with the board, I was actually able to get some sound for a split second while jiggling the Q2 transistor. I figured it might have a loose solder joint on the socket holding it in place, so I desoldered the socket and soldered the transistor directly to the board, but even after that I got no sound with the effect engaged.

After having done that, I realized my solder work on this board is so shoddy that I can't justify spending any more time trying to fix it when I have plenty of spare parts that I can use to make a new board, so I've scrapped this current board. I'm sorry if I've wasted your time, I truly appreciate all of your help! If my next build has issues I will be sure to keep you all updated, with measurements, pictures, and all.


I have done this more than once myself. I have found it quicker and less stressful to just redo the board than to spend a week trouble shooting a marginal solder job.

And if your question were a waste of time, no one would have answered. :thumbsup
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby dwmorrin » 26 Jan 2014, 14:06

I don't see shoddy soldering.
More to the point- our eyes are never the best judge of an electronic circuit.
Use your multimeter on low resistance or continuity beeper to check your soldering jobs.
Use the voltages to see what's going where.
If you have a loose connection, you're almost there.
Keep fiddling with it until you can figure out the bad connection.
Don't give up now!
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby ElSpeakoDelSpanisho » 01 Feb 2014, 18:54

SUCCESS!!11!1!!

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(yes, I know I wrote "of reach" twice, I wasn't paying attention while painting it)

I used some leftover parts and vero board to make a new board, and it works! Super fuzzy and crunchy, I love it.

The only problem now is that the LED doesn't light up. I have the positive end attached to a 2.2k resistor going to the DC jack, and the negative end going to the 3PDT switch.

Image

Thanks a bunch everybody! I owe you all a ton.
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby Duckman » 01 Feb 2014, 23:23

ElSpeakoDelSpanisho wrote:The only problem now is that the LED doesn't light up. I have the positive end attached to a 2.2k resistor going to the DC jack, and the negative end going to the 3PDT switch.

Looks like you need to ground this pin in your switch
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby bato001 » 02 Feb 2014, 15:34

Congrats on getting it to work. :thumbsup
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Re: Simple Woolly Mammoth clone refuses to cooperate

Postby ElSpeakoDelSpanisho » 10 Feb 2014, 05:38

Duckman wrote:
ElSpeakoDelSpanisho wrote:The only problem now is that the LED doesn't light up. I have the positive end attached to a 2.2k resistor going to the DC jack, and the negative end going to the 3PDT switch.

Looks like you need to ground this pin in your switch


Wow, tried this and it does indeed light up now, thanks a bunch!
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