No sound BYOC VB-2 (vibrato)

[HHR18]

Hi guys, I'm having a problem with my BYOC VB-2 clone. No sound at all, bypass works. Probing the circuit with my audio probe I have sound at emitter of Q1 and Q2 and at IC2 pin 3. After that, nothing. Would love you're help! Thanks in advance

BYOC VB-2 (Vibrato)
http://buildyourownclone.com/products/analogvibrato
Build instructions: http://byocelectronics.com/vibeinstructions.pdf
Layout: http://www.freeinfosociety.com/media/images/4078.jpg
Followed suggested layout 1:1 with the BYOC instructions and used exactly same components (provided by BYOC)

Voltages:

Adaptor voltage = 9.4v, no battery used

Q1 (BC550, npn CBE pinout)
E = 3,27
B = 2,2
C = 9,4

Q2 (BC550, npn CBE pinout)
E = 4,27
B = 4,79
C = 9,4

Q3 (BC550, npn CBE pinout)
E = 3,87
B = 3,38
C = 9,4

Q4 (BC550, npn CBE pinout)
E = 3,25
B = 3,77
C = 9,4

Q5 (2SC945, npn ECB pinout)
E = 0
B = 0
C = 0,13

Q6 (2SC945, npn ECB pinout)
E = 0,08
B = 0,56
C = 0,13

Q7 (2SC945, npn ECB pinout)
E = 0,13
B = 0,3 (seems to drop when probing)
C = 9,4

Q8 (2SC945, npn ECB pinout)
E = 0,77
B = 1,35
C = 3,34

Q9 (2SC945, npn ECB pinout)
E = 0,2 (seems to drop when probing)
B = 0,39 (seems to drop when probing)
C = 9,4

Q10 (2SC945, npn ECB pinout)
E = 0
B = 0,26
C = 0,27

Q11 (2SC945, npn ECB pinout)
E = 0
B = 0,20
C = 8,91

Q12 (2SC945, pnp EBC pinout)
E = 9,4
B = 8,88
C = 8,88

Q13 (2SC945, pnp EBC pinout)
E = 9,4
B = 8,88
C = 0,03

Q14 (2SC945, pnp EBC pinout)
E = 9,4
B = 8,77
C = 0,72

IC1 (4558)
P 1 = 4,90
P 2 = 4,91
P 3 = 4,89
P 4 = 0
P 5 = 4,84
P 6 = 4,9
P 7 = 4,9
P 8 = 9,4

IC2 (3207)
P 1 = 0
P 2 = 0
P 3 = 4,28
P 4 = 0,11
P 5 = 0,12
P 6 = 0
P 7 = 0,12
P 8 = 0,12

IC3 (3102)
P 1 = 0,12
P 2 = 0
P 3 = 0
P 4 = 0
P 5 = 0
P 6 = 0
P 7 = 0,09
P 8 = 0,11

IC4 (TL022)
P 1 = 0,7
P 2 = 0,37
P 3 = 0,53
P 4 = 0
P 5 = 4,6
P 6 = 0,77
P 7 = 0,77
P 8 = 0,13

IC5 (BA6110)
P 1 = 0,76
P 2 = 0,76
P 3 = 0
P 4 = 0,05
P 5 = 0
P 6 = 0,69
P 7 = 0,69
P 8 = 0,82
P 9 = 9,4

Diodes are not labeled on PCB, here I used D1 for the diode that is most left looking on the top of the PCB.

D1 (1N4148)
A = 0,72
K = 0,5 (seems to drop when probing)

D2 (1N4148)
A = 0,4 (seems to drop when probing)
K = 0,72

D3 (1N4148)
A = 0
K = 0,1

D4 (1N4148)
A = 0,1
K = 0,13

D5 (1N4148)
A = 0
K = 9,4

D6 (1N4148)
A = 0,77
K = 1,36

[armdnrdy]

Here are the IC voltages that I pulled off of BYOCs forum a few years back.



I built a version of this circuit...routing my own board...work and sounds great!

[armdnrdy]

This might help as well.

This is my redrawn schematic including the BA662 to BA6110 retrofit as in the circuit that you built.

[armdnrdy]

Taking a glance at the schematic, the working voltages, and your voltages...

It looks like IC5 (TL022) isn't getting voltage on pin 8.
One half of IC5 is the LFO. The other half supplies voltage reference.
Also, Q7 (945) supplies a reduced voltage (around 8 volts) for IC2, (MN3207) and IC3. (MN3102)
You should have 8 volts at the emitter.

There are two different 945 transistors. They have different pinouts.

2SC945 is ECB
KSC945 is EBC

Check which transistors were supplied.

You might want to post a few shots of both sides of the circuit board.
Many times another eye can spot a problem when you have looked it over for days. 

[HHR18]

Thanks so much for your pictures and help! I will post pictures tommorow and see which transistors were supplied!

[R.G.]

What does BYOC say you should do?

[HHR18]

What does BYOC say you should do?

Haven't contacted them yet, should I do that?

[R.G.]

Seems like they would known their product better than anyone, and ought to be interested in helping their customers succeed.

[HHR18]

I can't really tell which type of C945 transistors they are. One the back it reads C945 and after that GCA47. I will upload pictures soon, having some problems with uploading them Any clue which transistors these are? I would however assume BYOC supplies the correct transistors for the PCB. In there user manual they say it's 2SC945 with an npn ECB pinout.

[armdnrdy]

I would however assume BYOC supplies the correct transistors for the PCB.

First word of advise.....assume nothing....verify! 

After taking a glance at the build PDF...
it seems as if there are a few anomalies.

BC550 and 2SC732 are listed as having the same pin out, (CBE) when 2SC732 actually has a pin out of EBC.

2SA733 is listed as EBC when it is actually ECB.

The part number you gave for the 945 (C945 GCA47) leads me to believe that this might be a KSC945.

The 2SC945 uses a HFE classification of R, Q, P, & K.
The KSC945 uses R, O, Y, G, & L

The G following the 945 is most likely the HFE designation...which would make this a KSC with a different pin out.

Did you socket the trannys or solder them?

Once again....pictures would really help!

[HHR18]

First word of advise.....assume nothing....verify! 

Will do!

I also contacted BYOC a couple of hours ago, one thing I'm also not certain of is if have a newer or an older PCB board. They apparently made a mistake on the first batch of PCBs which should be solved by a jumper between pin 4 from 6110 and Q13 (see build guide). There is however nowhere V2 on my board and as far as I can see, no cut traces.

Unfortunately I soldered the transistors on there! Here are some pictures, if you need more or of specific areas I'll make some more:

https://dl.dropboxusercontent.com/u/137602/BYOC%20VB-2/C945.jpg
https://dl.dropboxusercontent.com/u/137602/BYOC%20VB-2/Front.jpg
https://dl.dropboxusercontent.com/u/137602/BYOC%20VB-2/Front%202.jpg
https://dl.dropboxusercontent.com/u/137602/BYOC%20VB-2/Back.jpg
https://dl.dropboxusercontent.com/u/137602/BYOC%20VB-2/Back%202.jpg

[armdnrdy]

Check this....and all solder connections for bridges and faulty connections.

The connection with the red arrow looks like C22 (10µf) is shorted.
That would cause the voltage running through R38 (10K) to be sent to ground, which in turn would cause no output at the emitter of Q7 (VCC2) which powers IC2, IC3, and other assorted goodies!

[armdnrdy]

Something else that came to my attention.

The above issue (C22 shorted) will cause IC5 (TL022) to have no power as well...as IC5 pin 8 is powered from the emitter of Q7.
My drawing depicts IC5 pin 8 being powered by VCC as per the original VB-2 factory schematic and verified on board shots.

BYOC changed IC5 power to VCC2.

It looks like fixing this one short may solve all of the voltage problems.

[HHR18]

Yeah I saw that one. That is because I replaced C22 because it looked bloated. I however already removed the connection and still have the same voltages as posted above. Any further suggestions which I could look at?

BYOC also responded and told me this:

Looks like you've got something shorted out around the TL022 and MN3102.  That's the best I can give you based on your voltages.  A signal probe would be a very useful tool here.  Try removing the MN3207 chip from its socket and using a piece of wire to jumper pins 3 and 8.  If you can hear dry unaffected signal when the pedal is on, then this means your problem is somewhere in the LFO/Clock Driver portion of the circuit.

I'm also gonna try their suggestion and see if it works. Thanks for help!

EDIT: Ok, so I tried there suggestion and indeed get a dry unaffected sound when connecting pin 3 to pin 8. There problem is thus in the LFO/Clock Driver right?

[armdnrdy]

If you jumper the BBD input and output...you will get dry signal.
The voltages are normal from the input to the output. (All of the trannys and IC1)

If you look at my drawing, note everything that is being fed VCC2, (output from Q7 emitter) compare that to your voltages...you'll see that everything that is being fed with VCC2 you listed as .12/.13 volts.

The voltage at all of those points should be around 8 volts.

You may have fried Q7. There is no voltage at the output.

Edit:

C22 looked bloated...did you have it installed with the polarity reversed?

[HHR18]

Ok, so I ordered 7 new 2SC945 trannies. Will replace Q7 (and maybe all the others) once they are in! C22 wasn't installed with polarity reveresed. That would be a real rookie mistake  Why?

[armdnrdy]

In the mean time...follow the VCC2 trace (top and bottom) to see if you can find any other shorts.

Another thing to try:
Pull all ICs that are connected to VCC2. Take voltage readings again on the power pins. (DIL8 sockets)
Use my drawing to see which pins are the power pins.
With the ICs removed if you get around 8 volts...then there is something wrong with one of the ICs.
If the voltage remains low....the problem is somewhere else.
That will rule out a bad IC.

[HHR18]

Mmm, I'm getting totally different readings with the BA6110 and TL022 ICs out. Here are my readings without both ICs in the circuit:

TL022
P 1 = 8,17
P 2 = 4,12
P 3 = 5,71
P 4 = 0
P 5 = 4,6
P 6 = 8,12
P 7 = 8,12
P 8 = 0

BA6110
P 1 = 8,11
P 2 = 8,11   
P 3 = 0
P 4 = 0,03
P 5 = 0
P 6 = 7,43
P 7 = 7,44
P 8 = 0
P 9 = 9,4

[armdnrdy]

The BA6110 isn't being powered from VCC2

IC2, IC3, and IC5 are.

Look at the VCC2 symbol connected to the output (emitter) of Q7 on my drawing.

[HHR18]

Reading with IC2, IC3 and IC5 out:

IC2
pin 5 = 0,19v

IC3
pin 1 = 0,19v
pin 5 = 0
pin 7 = 0

IC5 same as readings on previous post