10 min dirt & boost buzzes like hell..

[Brynngar]

Hi guys,
this is my first, noobish attempt to build a pedal. I followed the instructions and built a 10 min dirt & boost pedal,
with the parts from the diyguitarpedals shop. The bypass works fine, no humming here. When I turn on the pedal function, this happens:

Pot = 0% -> No sound at all
Pot = 50% -> only 1/2 of the usual sound, mild buzzing
Pot = 100% -> Loud buzzing, weak sound (maybe 80% of original)

Here are the pics, maybe someone can already see my failure. Otherwise I'll measure everything through and upload my results.




Thanks in advance!

Update: some measurements

+9v : 8,92 V
R1: 8,92 V
R2: 7,0 V
R3: 0.39 V
D1: 0 V
D2: 0 V
U1 (Transistor, top to bottom): 7,0 V, 0,93 V, 0,39 V
C1: 0,93
C2: 7.0

Btw, THIS is the schematic I built it upon: http://www.diyguitarpedals.com.au/shop/boms/10_Min_dirt_&_boost.pdf

[stonerbox]

Double check your ground connections. A badly or faulty connected ground will make the pedal hum like crazy. Also, check the orientation of the transistor pins. Collector (v+), Base (output) and Emitter (ground).

Edit: After comparing you pictures to the layout it seems like your transistor sits correctly, all good there. You better check all your cable connections one more time and check for iffy soldering points.

Full size pictures of your pedal (easier for others to check)
http://fs2.directupload.net/images/150723/wcdd8499.jpg
http://fs2.directupload.net/images/150723/7dwou3uh.jpg

[Brynngar]

Hi,
thanks, I will just resolder the whole PCB I guess.. What I'm still wondering about is the 0V at the diodes,
is that supposed to be like that?

Update:
I measured the resistances for all connections outside the PBC and got a 0.00 everywhere... So it seems that the fault lies
within the PCB.

Update:
I multimetered around a bit and measured all kinds of stuff, without gaining any insight sadly.
My results:

Connection between tips when in bypass: yes
Connection between grounds in bypass:    yes
No connection between tips when on:        yes
No connection between tips and ground:   yes
Correct resistor values:                               yes
Connection between the grounds:              yes

Could it be that the diodes are defect? The 0V issue there is still the only thing I find somehow odd
(with my limited knowledge on this field).

[Brynngar]

Pushpush! I still have no clue and it starts to get VERY frustrating.. If you need any more info/ measurements, just tell me!

On a further note, when I add the LED to the places where it's supposed to be, it starts to hum even louder than before (but works).

[mcknib]

Diodes / transistors /IC's don't like heat when soldering you should only apply heat from your soldering iron for about 4 seconds or use a heat sink like a small croc clip on the legs.

You should test the diode both ways and should get a reading in one direction. You're only looking to see if they are conducting in one direction so you should be ok leaving them soldered in place normally you'd have to remove one leg for accurate measurement. With these diodes being 1N34A's it's very easy to crack the glass body when bending the legs to fit the PCB but the effect circuit would normally still work but not as intended unless you've broken it through it's entire circumference creating a short circuit but you can of course switch the diodes out of circuit have you done that and if so do you get the clean boost?

http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/how-to-test-diodes-using-a-digital-multimeter.html

I'd look at your 3PDT connections your yellow IN wires look to be touching but it's hard to see.

With low effect volume that would suggest that your jack connection via the PCB IN and OUT may not be making a full connection i.e not fully connecting the signal from IN jack through the circuit to OUT jack and if you're saying there is no connection from the PCB to the jack tip(s) in effects mode like I think you are then your problem hopefully only lies with the connections from the PCB to the jacks.I'd re-do your wires to the 3pdt and make sure none are touching a few look to be.

[duck_arse]

brynngar - this is the circuit diagram link, yours was for the layout. we get upset when those two get confused:

http://www.diyguitarpedals.com.au/shop/boms/10_Min_dirt_&_boost_Schematic.pdf

that diagram shows that the diodes have one end connected to ground, and the other end has a capapcitor one side, and a resistor (pot) to ground on the other side. so, the cap will block dc voltage from the diodes, and the resistor connects that end to ground (0V). you have 0V DC on both ends of the diodes, and you have measured 0V, so this is good/correct/as expected.

can you measure the resistance between your board gnd/0V/earth and the case itself, please?

U1 (Transistor, top to bottom): 7,0 V, 0,93 V, 0,39 V

this also upsets us - please use C=7,0 B= ... etc, so no confusions possible. also, your voltages on the transistor suggest it is wired correctly.

[Teledimed]

Try this out:

http://www.diystompboxes.com/pedals/debug.html

Can be your best friend for diagnosing a circuit problem (along with the good folks here) 

[mcknib]

No connection between tips when on:        yes

Just to clarify does this mean you've got no continuity from the board in and out to the in and out jack tips when it's switched to effects mode?

[Brynngar]

Resistance between my ground and the case: ~1.0 at a scale of 200 on the multimeter. Is that possibly the reason ?

I checked the resistance between the case and the input jack, where the ground connection to the case is. There it also said 0.9 - 1.0.
So could it be that the input jack is either faulty or has a bad connection to the case somehow? Or is a value like that "usual" ?

[PRR]

Most meters won't read 1 Ohm or less correctly.

"about 1 ohm" (or the same as when you short the ohm-meter probes together) IS the right reading.

10 Ohms would be dubious. 100 Ohms might work in many cases but is surely "wrong", bad joint.

Is the case wide-open as seen in the pictures? Did you turn off all fluorescent lamps, soldering station, PCs, arc-welders in the area and try it? A wide-open box under a fluorescent is sure to buzz bad.