Please help - after a week solid first build still won't go.

[Naefunk]

So I am trying to build the DAM Meathead following the guide on http://tagboardeffects.blogspot.co.uk/2010/10/dam-meathead.html.

When it is plugged in the bypass signal is solid. When I activate the switch however it is just a "jack unplugged" sound. Constant buzzing - no change when guitar is strummed or potentiometer moved.

There are no modifications or part substitutions. As far as I know there are no "6.Positive ground to negative ground conversion" as nothing of the sort has been posted or mentioned anywhere.

Here are some voltage readings.

Where the 9V+ lead meets the board it reads 9.19.
Where ground leaves the board it reads 0.

Q1 (2N3904)
C 9.03
B 0
E 0

Q2 (BC182L)
C9.14
B 0
E 9.03

LED + 9.17
LED - 9.19





Off board wiring is based on http://gaussmarkov.net/wordpress/thoughts/wiring-up-a-1590b/

I don't know where to turn next. I am totally stuck. Thanks in advance.

[induction]

It looks like you've built the board upside down (meaning you flipped the layout vertically, the top row is where the bottom row should be, etc.) Assuming you're using the original transistors (or that they at least have the same pinout as the originals) you'll have to reverse them, too.

Pop out the transistors, rotate them 180 degrees, pop them back in, and report back.

[Naefunk]

Thank for your reply.

Transistors flipped and same problem. I don't think I've built it upside down. What makes you think that? I compared what I was doing before hand to other builds out there. The diagram I looked at (the first one on the link to the website I followed) I did essentially this :

The board is facing me copper side.
The components are basically showing through the board.
For instance the first component, starting from the left (a 10nF polymer capacitor) goes in 2 rows down, one in from top left and one row in from bottom left so that when I flip it over horizontally I solder it in 2 rows down, one in from the top on the right  and one row in from the bottom on the right.



I soldered the board as if I am seeing the copper face with xray vision. Does that make sense?

[canman]

When I look at the copper side of your board, I see two cuts.  Now, when I imagine the board being flipped over, those cuts are in the wrong spot.  I agree induction, it seems like the layout has been built upside down.  Input should be at the bottom left, but looking at your PCB, the input is only at the top left, or bottom right, depending on how you position the board.

Not saying it won't work the way you built it, but it's going to be much easier to debug if it's been built exactly as the layout shows.

One thing worth doing if you're planning on building more pedals, is to throw together an audio probe.  Then follow the schematic, probing each side of each component, starting from the input, and see where the signal stops.  http://www.diystompboxes.com/pedals/debug.html

[Naefunk]

I'm sorry but I don't understand what you mean. Maybe I'm being daft but I'm confused. Here is the copper side of the board again.


Directly next to the input, before the cut on the bottom row is the leg of the 10nf cap. Is that not how I should be viewing this diagram? Sorry for the derp.

[duck_arse]

the big 47uF cap is backwards on your build.

always look at the board from the component side. poke a lead thru from component side where the orignal diagram indicates each cut, then tell us how far out your actual cuts are.

I give you extra points for the interesting upside-down-ness of the whole build, though.

[edit :] oh, and those guys have no good manners: welcome to the forum.

[induction]

I soldered the board as if I am seeing the copper face with xray vision. Does that make sense?

Yes, it makes sense, but it's wrong. The layout is drawn so that you are viewing the component side. The copper and cuts are positioned as if you are seeing them with X-ray vision.

I see a possible cold solder joint in the very center of the board, and another one just below and to the left of it in the photo. Try remelting all of your joints.

I also second the audio probe.

[Naefunk]

Again - thank you for your prompt replies. I've had to leave the house for a bit.

I will reply as soon as I get in. Cheers for the welcome. If I've built this thing upside down TWICE...well that'll just be plain funny.

Speak to you later.

[Naefunk]

Here is a picture of the board with leads sticking out from where the cuts should be and marks where they are.



RE - 47uF cap : it's negative side should be facing towards the bottom of the board and there is an arrow on the cap with a "-" symbol on it, presumably indicating that that is the negative facing direction. By my logic (which we've established may not be sound) it is facing the right way (?).

[Naefunk]

And if I understand what you're telling me : looking at this diagram



I am looking at the component side as it is and using my magical xray vision to see through to the copper side and where the cuts are - whereas previously I assumed the opposite?

Nobody told me how this worked I just made an educated guess by looking at other peoples builds online and looking at where their components were.

[induction]

Now you've got it. And I agree, your caps are oriented correctly for the way you built the board.

[jimilee]

It is built backwards, which in itself is very impressive and should work fine I'd think. The stripe side of both electros are the negative side. Don't feel bad, I've seen a layout built completely in the copper side. Also, I believe your trannies should be flipped 180 degrees.

[mth5044]

Something is wrong with your voltages as well. You shouldn't be getting full voltage to your LED, and there should be a voltage drop across it. Your transistor voltages are also way wrong - I'm guessing it's because your layout is backwards, but can't be sure. This circuit is basically a fuzz face with a dimed gain control, so you can compare your voltages to that.

[GGBB]

It looks like it is built properly (although mirrored). Check your solder joints and check your switch. Also check for shorts between adjacent strips, and make sure the cuts are complete (can't make them out clearly enough from the photo).

[LightSoundGeometry]

Ive been tying to build one of the fuzzes from the vero layouts there on that particular website for 4-5 months now. I am convinced they are not verified , and checked, and may not be laid out properly ..99.9% of the stuff there I try does not work..I think I tried the colorsound one knob and the mosrite each at least 100+ times ..probably wasted a 100 bucks in parts in doing so ..

probably just me - but since the stuff there never turns out, I have been forced to BB myself and now create my own layouts. I still cannot get a fuzz to turn out ..I think its the lack of proper transistors in my case now . I think I can BB a circuit up to 15-20 components now except a fuzz of fuzz type effect. the closet i got was the escobedo tightwad fuzz but it sounds like a distortion and not a fuzz

[LightSoundGeometry]

I'm sorry but I don't understand what you mean. Maybe I'm being daft but I'm confused. Here is the copper side of the board again.


Directly next to the input, before the cut on the bottom row is the leg of the 10nf cap. Is that not how I should be viewing this diagram? Sorry for the derp.

I see a cold unsoldered joint on copper side - row 5 from the top left and to my left is a cold solder joint for sure

blue input wire looks like a bad solder joint as well ..need to reflow the tracks to make them smooth and cover the leads properly

row 6 and to the left looks like a suspicious solder joint as well..

I see at least 3 suspicious solder joints

[mth5044]

Ive been tying to build one of the fuzzes from the vero layouts there on that particular website for 4-5 months now. I am convinced they are not verified , and checked, and may not be laid out properly ..99.9% of the stuff there I try does not work..I think I tried the colorsound one knob and the mosrite each at least 100+ times ..probably wasted a 100 bucks in parts in doing so ..

probably just me - but since the stuff there never turns out, I have been forced to BB myself and now create my own layouts. I still cannot get a fuzz to turn out ..I think its the lack of proper transistors in my case now . I think I can BB a circuit up to 15-20 components now except a fuzz of fuzz type effect. the closet i got was the escobedo tightwad fuzz but it sounds like a distortion and not a fuzz.

If you read a few of the comments, the layout has clearly been built by more than a few people with success. Tagboardeffects is the site for vero layouts, dozens of comments on each layout with successes, debugging, etc. I just looked at the Mossrite that you mentioned - quite a few people commenting on their success, one even saying this was the best sounding layout of a few different ones. I'd first question your building skills, considering you are not only having trouble with vero, but mention breadboard as well, before slandering a website that has done an incredible amount of work for the community without any type of profit.

[Naefunk]

tagboardeffects is rated across many different forums and builders and yes, their forums are littered with success not to mention endorsed by parts and electronics vendors.

They are not the problem, that is for sure. It's me.

Thanks for you comments everyone. I now know what I need to do before I progress any further. I'm off to cut a new board and start at the beginning. Some may call that an unnecessary step. I feel that every mistake is the best lesson I could hope for and I can only further my skills and confidence in myself by doing so. My soldering improved tenfold when I had to move all the parts to a new board (yes, it's not the first time I'm doing this.

If it still doesn't work after rebuilding it the right way - I'll be back. If it does work I'll be back to shout it out, from the rooftops, baby yeah!

Thanks a bajillion million. +1 to everyone.

'Mon the forum!

[mth5044]

Good luck man! I think building it mirrored isn't helping to figure out what's going on, so that's probably a good first step.

[J0K3RX]

You coulda de-soldered your parts, flip the board over and solder them on the copper side of the board.. should work. Just forgt the x-ray vision and all that and build it just like the pic. Or, make a new board..