Please help a total noob with 1st build issue! (DIY distortion pedal kit)

[djhollowman]

Hi all.
As stated, I'm a total noob - this is my first DIY build. It's a distortion pedal kit, "Metal Mother" from www.diypedals.com. I have contacted them for help, but I've not heard back and now the site is down, so here I am for (hopefully!) some pointers from you good folks.
Having built up the kit I find that I get the clean guitar signal through the pedal with no problems (this is the case if the pedal is connected to the power or not) however as soon as I press the switch to power-up the effect the signal dies completely - no sound at all. The LED lights up, but there is no sound. The volume and gain pots have no effect.
Here's a picture of the schematic I got with the kit:



Having read the DEBUGGING page, here are my findings:

1.What does it do, not do, and sound like? Guitar sound is present when plugged in but not switched on, whether power is switched on or not.
2.Name of the circuit = "Metal Mother" from www.diypedals.com
3.Source of the circuit (URL of schematic or project) = Their site is currently down so I can't post a link.
4.Any modifications to the circuit? Y or N No.
5.Any parts substitutions? If yes, list them .No.
6.Positive ground to negative ground conversion? Y or N I don't know what that is, so I'll say not as far as I know.
7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? => It is powered with a power supply, not 9v battery. The power supply reads 10.9volts with centre negative.
Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead = Now I'm a bit lost.
Voltage at the circuit board end of the black battery lead =


OK, I'm a bit lost now!
However, here are some other things I have tried:

- the switch is good and wired correctly
- 10.8v is getting to the circuit board
- the jacks, circuit board and switch are all correctly grounded
- the transistors are definately in the correct way round
- the LED on the circuit board is correctly orientated
- I have the circuit out of the enclosure

I should point out that when I originally wired the 'board, I installed the 10uF 35v capacitor backwards. I have since replaced the cap with a new one and correctly orientrated it, but still have the problem - could I have damaged something else within the board by having that cap in backwards?

I'm also confused as to how to wire up the pots - the instructions are a bit vague and they were clearly meant for a situation where you connect the pots DIRECTLY to the board. As this was not physically possible inside the enclosure I got with the kit, I had to connect the pots to the board with pieces of wire, and I'm not 100% sure I've got this correct either. Specifically, on the schematic where it says "Gain 2&3" I connected the 2 pot terminals together and ran a wire to the appropriate point on the board - is this right? The pots don't appear to do anything, but is this just because there's a fault with the board???

I would really appreciate any help with this pedal - it's driving me nuts!!! I can happily supply more info/photos/whatever is required.

Thank you.


Can't get photo to show up! I've uploaded a pic to Flikr, but I can't make a link work in this post?
http://www.flickr.com/photos/101459828@N02/9700749984/

[pappasmurfsharem]

diypedals.com for me forwards to madbeanpedals.com
doing a whois on the diypedals domain seems to show that Brian the proprietor of madbeanpedals.com is the owner of the diypedals.com domain.
It would appear that he has owned that domain for some time.

After some quick googling it appears that you mean diypedalkits.com
which appears to be owned by Kevin Duncan. there is an email registered with the domain which email address did you use to try and contact them?


I posted the image for you here.

Ill try to get a quick diagram up on how to connect the pots

[djhollowman]

Hi, and thanks.
Yes, you're right, I meant www.diypedalkits.com!
I have contacted Kevin through the contact form on the above site at the above site, and he said he would going to reply with help but that was a week ago, so I figured I'd ask here as well.
Thanks for posting the photo - could you mention how you did that please? I tried 3 different ways but none of them appeared to work for me, thanks.

Could it be that I simply have the pots wired up incorrectly and that is all that's wrong?

[GibsonGM]

SOMETHING isn't connected right.  You have to go back over your build, and make sure all the parts are in the right way.   AND you have to make sure there is no solder making a 'bridge' between 2 places it should not (that's a short circuit!).  I wouldn't think your pots would do what you're reporting.  A short somewhere would.

From the sounds of it, SOMETHING is shorted, if you have sound going thru with no power applied.  What you really do need to troubleshoot is a schematic.   Did you use VERO board, and did you cut out the "X" spots on it?

Yes, "gain 2&3" means pins 2&3 on the pot are connected together and run to the board there.

When you read voltages on a PCB, you clip the negative lead of your meter (black) to the ground, or battery "-" terminal with the battery plugged in.   Then you probe with the "+", or red, lead to read voltages.  You have to be VERY careful not to short things with the probe, like transistor legs!  Only touch one place at a time or you'll damage something.

[pappasmurfsharem]

Its to fuzzy for me to see what the Orange thing on the right is on the pic so I didn't include it. Is that an LED??

The picture mentions a tracecut under r1 and r3 but it doesn't make sense to have one under R3. So I assumed it was under the lower section of r1 (this might not be correct however) also NOTICE the tracecut under the horizontal 100n cap.

Take pictures of the Top and Bottom of your board.
Try to get them as clear as possible, and try to keep the wiring in perspective so we can easily see where they are terminating.


See Diagram here for wiring....

.....

to add the image here I Clicked on your Link -> Right Clicked the image -> Clicked Original -> on new page right clicked image again -> Clicked Copy Image URL.

Then you would do the following

Code Select Expand

[img]<place URL Here>[/img]
so in your case it would look like this in the text edit box.

Code Select Expand

[img]http://farm6.staticflickr.com/5328/9700749984_f2e806fec9_o.jpg[/img]

[djhollowman]

Ah, thanks for that.
Here are some pictures of how it looks now, before I've made any changes to it.
http://www.flickr.com/photos/101459828@N02/9701986844/
http://www.flickr.com/photos/101459828@N02/9698753235/
http://www.flickr.com/photos/101459828@N02/9701993388/
http://www.flickr.com/photos/101459828@N02/9701996830/
http://www.flickr.com/photos/101459828@N02/9701998238/

Hopefully these will help.
And yes, the orange thing on the right is an LED (I didn't get any value info etc about it)
The tracecuts were already there on the board as part of the kit.

I think I'll await more comments before breaking out the soldering iron just yet!
Thanks!

[peterg]

I'm working from a handheld so I can't see the pics too closely but I see a couple things you should double check...

May sure there are no bridges between the rows of solder. Run a knike along the rows if you haven't done so already.

There are a lot of wires running to you power jack. The neg from the battery snap and a wire from the input jack switch should connect to the large neg lug. The power wire to the board should connect to the lug furthest from the neg lug. The batt snap pos should connect to the middle lug

All you neg wires need to connect with each other.

I can't tell if your switch is wired properly but you should double check it.