Pork Barrel Chorus without vibe

[desmoben]

Hi from France and thanks for this website,
I just finished my pork barrel chorus, but I experience some trouble:
first of all, I removed C4 due silver mica cap with larger (I don't know the word in english) than drill hole on the pcb. I will put a ceramic disc instead of silver mica tonight.
But I think that does not explain my problem:
When I put the effect ON, I have sound but only the regular sound of the guitar. When I put the vibe switch on, then I have no more sound.
I received MN3007 and MN3101 with the (same word I don't know, but I hope you will understand) nearly broken. I put them back straight to fit in the socket.
I have one multimeter to test, but I don't know how to begin the testing.
Could you please give me some tips.
Thanks in advance for anyone that may help.
Best regards,
Benoit.

[bigmufffuzzwizz]

Hey Benoit, sorry to hear your experiencing problems but we can do our best to help you.
I think the word your looking for is "leads" which would be the metal legs on a component that you solder to the pcb. I don't think your problem has to do with the silver mica. If your only getting clean sound and no effect when the chorus is on, then we gotta figure out whats not letting the chorus signal through to blend back with the clean. It sounds like you probably wired the vibrato switch wrong which if its that would be a really easy fix. Could you post clean, clear large photos your build. Try to get everything, top of the board, bottom solder joints and your wiring (especially the vibrato switch). 

[desmoben]

Yes, that is the word I was looking for.
I do not think I have a problem on the switch VIBE because it seems to work properly (it put the vibe and regular guitar with OFF and vibe only when ON).
I think I have problem between C8 and mix pot on the chorus part of the effect.
I can make pictures of my work, but I think I will have to do a audio probe if nobody can give me what would be Voltages VB, VD  ...
I never experienced any problem on my DIY projects, it is now time to get one's hands dirty!
If I am able to fix and measure the VB/VD, I will try to post it to help?
Thanks for your reply,
Benoit.

[bigmufffuzzwizz]

It seems like you have some grasp on what your doing. I'd advise building an audio probe, it's always handy to have and its so cheap to make one. I haven't build this so I couldn't give you voltages but someone should have one who can.

[desmoben]

Hi all,
now, I think I need your help:
I have build my audio probe (I will keep it, very usefull).
But doing my tests, I have seen that the 9V battery was extremely hot (it hurts me while removing the battery from its socket).
I will continue my tests when battery will be colder but do you have any idea why my battery become hot when I plug it?
Thanks in advance for your answer.
Best regards,
Benoit.

[desmoben]

For helping: I have tested the sound until R19 and until R19 I have the guitar regular sound.
I have no sound on R28 and R24.

And I have tested 8 pin of IC4, and it seems that I have sound only on pin3 (connected to R19).
(hard to do a test with my probe on IC but it seems that I have only guitar sound on IC4 Pin 3).

What test could I do?
Does it means that IC4 is out of order (as I supposed first when it arrives with all legs nearly broken)

Thanks in advance for your answer.

Benoit.

[bigmufffuzzwizz]

Your in the right direction. If your not receiving any signal besides whats going into the chip then I would assume that chip isn't functioning at all by what your saying.
I would recommend getting another one. You could try to contact the distributor you got your chip from originally and see if they will replace it for you, mention the leads being almost broke etc. Might not be worth it as they are relatively cheap. I've seen them for about $5 on ebay. It is possible IC4 is all that is wrong with your build. 

[gtr2]

I wouldn't just look at the chip.  Your battery should not be hot like you say.  You have a voltage issue in my opinion. You'll never get a chorusing with incorrect voltage.  Pictures may help.  Double check your component values in the power section of the schematic for VD and VB.  Also check for a short to ground.  Is the pedal boxed up?

[desmoben]

First of all, thank you all two for your input.
I have find another chip on ebay and I am now waiting for it (from another country it will take some days :-( ).
I will check voltages and send a picture of my pedal (not boxed yet : rock it before boxing it!).
I will wait until next IC receipt before sending picture.
As promised with other people whose pork barrel did not work, I will also send the voltages when I will solve my problem.
I will give you news when I will install new IC4.
Thanks again,
Benoit.

[gtr2]

I'll say it again    Your battery should not be hot to touch.  This means too much current is flowing due to little or no resistance between the positive and negative terminals of your battery.  There is a short in your circuit somewhere.  Possibly a bridged joint in the power section of the pcb...

Josh

[gtr2]

Pictures of both sides of the board and your wiring may clear this up faster.

Josh

[desmoben]

Thank you very much for your prompt reply.
While taking pictures, I realize chekcing again all components that D3 was not in the good way. That is way I remove my previous message but I did not see you already answered it!

Here the picture of the BAD D3:




I will keep you informed and I will post the voltages of Q when I will fix this pedal!
Benoit.

[desmoben]

I have fixed D3 and measure Voltages on

9V : 7.88V

VD : 7.81V

VB : 4.41V (I assume it depends on my trimpot position)

Still no sound after IC4.

Voltages on IC4:
1 : 7,81V
2 : 3,82V
3 : 3,69V
4 : 7,27V
5 : 0V
6 : 3,80V
7 : 6,50V
8 : 6,50V

Does it means that IC4 is dead?

Am I not supposed to have sound on pin 7 and 8?

Benoit.

[gtr2]

You should have sound on 7 and 8.

Try a new battery so your operating at a higher voltage.

Josh

[desmoben]

Hi,
I have tried with a 9V boss (delivers 9,48V), and I still have no sound.
I am waiting my new IC to check with another IC as the one I received first had legs nearly broken.
I will keep you informed.
I hope I will success in that debugging, cause I have sold my small clone and I want this chorus :-)
Benoit