Author Topic: Bionic Guzz Fun kit : no sound :-(  (Read 3952 times)

bgf2016

Bionic Guzz Fun kit : no sound :-(
« on: September 18, 2016, 05:17:55 AM »
Hi

I'm currently stuck on this kit, with no sound or hum at all coming from the pedal.
First time doing a pedal kit, but not first time soldering and have already completed Shruthi XT synthesizer without problems (http://mutable-instruments.net/shruthi1/build/digital_xt) (note : step by step detailed tutorial).

I have no idea of what could be the problem, could you please help me ? Thanks

1.What does it do, not do, and sound like? No sound coming from the pedal, no buzz or hum.
2.Name of the circuit = Bionic Guzz Fun kit - Board-mounted version, from Fuzzdog (unable to provide support at this moment).
3.Source of the circuit (URL of schematic or project) = http://shop.pedalparts.co.uk/Bionic_Guzz_Fun_kit_-_Board-mounted_version/p847124_12169773.aspx
                                            http://pedalparts.co.uk/docs/BionicGuzzFun-OBP.pdf
4.Any modifications to the circuit? No
5.Any parts substitutions? No
6.Positive ground to negative ground conversion? Not sure, but apparently negative ground.

- transistors and electrolytic capacitors are rightly oriented I think.
- Double, triple checked parts placement and resistor values.
- Transistors are on sockets, so they shouldn't be toast.
- checked the PCB for bad solder joints, resoldered those that could pose problem (I'm not a pro, but it's not my first time soldering, didn't have any problems).
- Currently in testing mode, no switches (see PDF p.4). Tested wiring with meter in "sound mode", seems ok.

Battery voltage = 8.58V
Voltage at the circuit board end of the red battery lead = 8.57V
Voltage at the circuit board end of the black battery lead = 0V

Q1 (2N5089)
C = 6.83V
B = 4.49V
E = 7.43V

Q2 (2N5089)
C = 6.84V
B = 3.2~2.9V
E = 7.3V

Q3 (2N5306)
E = 0.39V
C = 6.25V
B = 0.8~1V
(values apparently affected by "FUZZ" potentiometer position)

Verified that the voltage on the (+) pin is more positive than the voltage on the (-) pin.

Google Photos album : https://goo.gl/photos/fYYDzARa2pFYC2YcA
(Yellow wire : output
green wire : input)

Vinnie500

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #1 on: September 18, 2016, 06:27:20 AM »
Have you seen/made an audio probe, it's really useful for no sound problems. http://www.diystompboxes.com/pedals/debug.html
I just put a drilled a hole in a medicine bottle put in a jack and soldered on some coaxial cable with the capacitor the thick copper of the coax makes a great probe.
Just start at the input and move along and see where the signal stops. I find doing this it also helps me spot things I've missed.

bgf2016

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #2 on: September 18, 2016, 06:53:56 AM »
Thanks for the response

Unfortunately I don't have any spare caps at the moment. I'm planning to make an audio probe, but also wanted to post here to see if someone could immediately see what's wrong from experience

Vinnie500

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #3 on: September 18, 2016, 07:13:01 AM »
I'm new to this as well but I think any more experienced people will need a bit more info to be able to help. Did the kit come with a schematic?

bgf2016

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #4 on: September 18, 2016, 08:52:14 AM »
Yes, all the info is in the kit PDF : http://pedalparts.co.uk/docs/BionicGuzzFun-OBP.pdf

rutabaga bob

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #5 on: September 18, 2016, 09:53:56 AM »
Edited - comment removed.
« Last Edit: September 18, 2016, 10:34:39 AM by rutabaga bob »
Life is just a series of obstacles preventing you from taking a nap...

I cant resist a filter - Kipper

M.A.P

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #6 on: September 21, 2016, 04:46:04 AM »
Your pictures show that there is no oscillation switch soldered in.

Connect the switch as shown in the PDF or solder a bit of wire between the pins S1 and S2 instead. Also check the solder joints on the FUZZ pot. It may just be the picture but they look strange to me.

Hope you get that thing working  ;)

Greetings from Germany
Marcus

Hemmel

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #7 on: September 21, 2016, 10:56:19 AM »
^^ +1 on what Markus said

If nothing links S1 and S2 (or S2 and S3) then both Q1 and Q2 transistors don't have their collectors grounded.
As Markus said, put a jumper between S1 and S2, unless you already have a switch for oscillation, then solder that in.

B.

bgf2016

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #8 on: September 21, 2016, 01:50:46 PM »
 ::) Of course !

what a dummy I am !

I didn't remember that auto-oscillation switch was mandatory, or to be bypassed, since I chose the footswitch option instead of standard PCB mount.
I'll email fuzzDog to advise to put a warning in the pdf especially for scatterbrains like me.

It's a case of "shouldn't have done a test mode" ;D, it works fine now.

I should have looked more closely at the schematic, wouldn't have wasted your time, sorry for that. Thank you very much guys for pointing the obvious !

Hemmel

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #9 on: September 21, 2016, 02:06:43 PM »
If our replies helped, then no time was wasted.

Good idea to warn fuzzDog about this.

Happy to see that it works now.

Go on and play ;)
B.

M.A.P

Re: Bionic Guzz Fun kit : no sound :-(
« Reply #10 on: September 22, 2016, 01:56:34 AM »
Good to hear you got it working bgf2016 :icon_biggrin:  I like to help others with debugging because it helps a lot to understand the different circuits and the more possible errors you know the easier they're to find at your own projects. It's definetely not a waste of time ;)
The easiest mistakes are often the hardest to find. I have made a lot of stupid mistakes since I'm building pedals ::) :icon_lol:

The building description is really puzzling. First it says now you can test the pedal and a few pages later it tells you how to wire the oscillation switch.