Honey bee clone not working. HELP PLEASE!!!

[alfonso_bundis]

Hello everyone,

I just built a Yellow Shark (http://www.madbeanpedals.com/projects/YellowShark/docs/YellowShark.pdf) , a Honey Bee clone, using a home-made pcb. When the pedal is engaged I get no output. I used a probe and realized that the problem seems to be in the transistor since I get some signal at the gate but none on the source or drain.
My voltage readings are the following:

ic
0.06
4.24
3.09
0.00
0.06
4.25
8.54
4.46

trans

G 0.00
S 0.00
D 8.45

I tried changing the transistor but the problem persisted. I get those voltage readings even when there is no transistor in the sockets.
The soldering seems to be kind of ok and I cannot detect any shortcircuits or interrupted paths.
Hope these pics help.





I had to replace the non polarized 1uF capacitors for electrolytic ones.  The positive end of C6 was connected to R6 and the positive end of C11 was connected to R12/Q1.

Thanks in advance for your help.

[aion]

My money would be on the PCB etching... it could be OK, but the traces look pretty rough around the edges, so you may either have a bridge or a broken trace someplace.

[R.G.]

When the pedal is engaged I get no output. I used a probe and realized that the problem seems to be in the transistor since I get some signal at the gate but none on the source or drain.
My voltage readings are the following:
[...]
trans
G 0.00
S 0.00
D 8.45

Your intuition is correct. You get no output because the transistor is not conducting. The drain is at the power supply potential, and that means that the voltage across the drain resistor is zero, and that can only happen if the current through the resistor is zero. Likewise, the source is at 0V, and that means there is no current through the source resistor.

The source should be at a volt or two above ground if it were working correctly.

Possible causes include
- wrong transistor, not a JFET 2N5457
- right transistor, inserted into the wrong PCB holes
- PCB problems
- soldering problems; there is at least one place in the photo that looks like there's a solder tread lapping over two traces that should be isolated, but it may be that the source of the JFET or resistor is not really making contact inside the solder "joint".

[Les Paul Lover]

Difficult to say with certainty, but the soldering looks like it has bridges in many places too?

This may have no impact depending on whether they should all be directly connected or not, but i would recommend using thinner solder wire in the future.

And yes, the pcb traces don't look great, but I feel harsh saying this as I've never etched one yet.

[midwayfair]

Use your multimeter, not your eyes, to figure out if there are solder bridges.

[alfonso_bundis]

Hi guys, thanks a lot for all your replies.
I tripled checked my paths but I am still unable to fine any bridge or any damaged path.
Will try o do it a couple of times more.
I did some tests with the sound probe. If I connect the sound probe to the output cable I get signal up to the gate of the transistor. Connecting the probe to the input jack I can get signal starting from the transistor drain.
The values of the resistors and capacitors seems to be OK.
Is there something else I could try?

Thanks for your help.

[antonis]

 
Maybe I'm missing something or you connect your probe wrongly..

[alfonso_bundis]

Maybe I'm missing something or you connect your probe wrongly..

Sorry, I guess I didn't explain it clear enough, or maybe the test it self made no sense.
So, I am not getting any sound signal from the output of the honey bee.
I checked the soldering looking for cold joints, bridges, and discontinuities but found none (probably I should check again).
I used a sound probe to pin point where does the signal stops, it turns out it is at the transistor gate.
Commonly the sound prove is connected to the sound source to find where the signal stops.
I tried doing the opposite, connecting the sound probe to the amp and scan the circuit backwards starting from the output. the idea behind this was to confirm whether the problem is in the volume pot, he resistors and capacitor before the pot,  or any other point. Doint this I saw that, going backwards, the signal stops at the transistor drain.
Since I am still unable to find any bridges I guess the problem is just the transistor.
Is there a way to check if the transistors I have are OK? or any other transistor I could use to check if the problem is the circuit r the transistor?

Thanks for your help

[antonis]

the signal stops at the transistor drain.

If get it right, you do have signal on junction of Drain/R12/C11...

If so, then you have to check for "open" C11, continuity between right leg of C11 and R13/C12 AND possible C11 right leg grounding (straight or via R13..)

[alfonso_bundis]

Good news everyone, I finally solved the issue.
After checking the board for bridges and broken paths without any success I abandoned the project for a couple of weeks to clear my mind.
Today I decided to try some other transistors, I bought another 2n5457, and BC255C and a 2N3819 as replacements. The first one did not work, the second one let signal pass through but with a lot of volume loss and the third one made the trick. Probably there is a bad batch of 2n5457.
Thank you everyone for all your suggestions and help!!!

[pappasmurfsharem]

If the 2n3819 works then you would probably need to bend the legs for the 5457 to work

2n5457 pinout


2n3819 pinout

[alfonso_bundis]

In fact i had to bend the legs of the 2n3819 to make it work so he drain, source and gate legs matched the holes intnded por the 2n5457

[pappasmurfsharem]

Hmmm bad luck I suppose.