I have 0 output on my cosmo, but bypass signal works fine. LED lights up when I hit the switch, but I get no sound at all. Any ideas? I'm about to hit it with a signal tester, but I would like to have your input on it as well.
I have output at the 9.1 Zener, I have output at C2, but I lose it after that. So frustrated.
And of course, I"m out of soldering braid. fml.
So here's what I've worked out so far. I am getting a signal through; however, fuzz knob is completely unresponsive, and it is a clean tone passing through. What is the pin layout for the NPN germ tranny on the pcb?
The pinout orientation should be as follows: emitter on top (toward gain pot), base in middle, and collector on bottom (toward r11). It sounds like it could definitely be an issue of a backwards or faulty transistor. If that doesnt work, check orientation of the other trannies also.
I think it's a faulty tranny. I'm going to stick an NPN silicon transistor in there and see if i get anything.
Are you using the npn I sent you? That should definitely be working. I tested a solid gain of 50 on those. The emitter is the little tab on the bottom. Try an npn silicon and see how it works. If it is the tranny I can search through the pile again and find another to send.
Little mixup. The GAIN knob is unresponsive, not the fuzz knob. The fuzz knob will increase in volume, but there is no added fuzziness or gain.
EDIT: Gain knob coincides with the transistor. Labels confused me for a bit.
Running out to Radio Shack right now to pick up an NPN sili tranny and some desoldering braid. I'll check in in a couple hours.
Sounds like something might be up with the mosfet stage. The gain knob should increase the signal level into the fuzz stage. Did you use a bs170?
Oh yeah I see now. The gain is actually what I would call the fuzz. It does control the gain of the npn germanium. Man I'm sorry about that, when I get back I'll try and test a few of mine to see what's up. Just to be sure it says 2n1304 on the top right? I hope I didnt mail you a pnp on accident. BTW do you have a gain tester?
I am getting signal from the BC109, but the signal breaks down somewhere before it hits the transistor. You sent me a 2n1304, it's the right one. I don't think it's the tranny. Trying to trace the signal path. After it hits the BC109, where does the signal go?
Oddly enough, I accidentally put the transistor in backwards, and I was getting signal. Now that I have put the transistor in the correct way, I get dead output.
After the bc108 the signal goes straight into the base of the germanium transistor. Your most conclusive test will be to replace the germanium tranny with a cheapo silicon one and see if it fuzzes like it should. Are the transistors in sockets? That posisiton should probably be socketed. Heat causes diffusion of the semiconductor dopant ions that are critical to the operation of the device, too much heat and it will fry. I would also test the gain using keens simple DC tester to see if it still is around 50 and the leakage is still low. What is the voltage measured from the npn germanium transistors collector and ground?
I am using an audio probe atm, can't find my dmm. All 3 Q components are socketed. If this is the case, I am not getting any signal to the base of Q3. I have signal coming into the BC109, but lose it after that.
A little more accurately, I have signal on the middle lug of the BC109.
WOW. I don't know what I just did, but I saw sparks and smelled burning.. Think I just blew my zener somehow. wtf.
EDIT: So I didn't blow the zener. I took out the BC109 and put the 2n4401 in there to see if I can get any signal to pass through. Something passed through alright..sparks galore.
Zener is still passing signal..I think I'm good on that front. Jesus, this is one of the easier builds I"ve had, why am I having so much trouble?
:o crazy. That doesn't sound good. If you are not getting a signal out of the collector of the bc109 the collector might be shorted or the bc109 could be bad. Sparks indicate that something is shorted. The zener is definitely the first thing i would test, the BS170s are notorious for burning out really easily too.
Screw it. I am going to buy a new BS170, new Zener diode, and a new BC109. SUCH a headache. I don't understand how the BC109 could have shorted to begin with, though.
The 2n4402 defnitely shorted. There's a chunk of plastic missing at the collector.
It sounds like there is just way too much current passing through that position. maybe one of the resistors off of the collectors which connect to the power supply is bad. I would break out the continuity tester and see if there is a short between the two lugs of power supply.
definitely. I'm hanging it up for tonight, though. Just getting more and more frustrated. gonna start from square one tomorrow.
it works! It was a bad BC109.
Thanks, Jake, for all the help. As frustrating as this whole ordeal was, I'm glad I went through it. I've substantially improved my schematic reading ability as well as my ability to troubleshoot.
the transistor sounds great, I'll post up a clip when I get everything buttoned back up!
Glad to here you got it up and going, way to stick with it !!
This thing is FUN!
It's so versatile. I can go from light overdrive to over the top fuzziness all in one pedal. Jebus, why didn't I get this sooner?
Sweet! Glad you got it working. Definitely one of my favorites. Everyone should have one ;D