Help Please For an IC Problem

[Peppercorn]

Hi all
I'm a newbie but I am trying to teach myself and understand how all this works.....I'm gettin there!

I decided to build the Soul Preacher Compressor and made the pcb and checked for any faults or shorts and everything seemed fine! I built the "Soul Preacher" Compressor from this site.....

http://www.aronnelson.com/gallery/main.php/v/MarkMs-Gallery/album15/album76/Soul_Preacher_revision_7_LAYOUT.gif.html

I have used all of the correct components except the diodes which were 1n415's I think.

I have put all the electrolytic caps in the right way and "as far as I know" have made no blunders!

I have plugged it in and added power and I get no sound at all.

I then used a trace lead to follow the signal through and it worked up until pin 3 of the IC.

As I understand the IC pin 3 is the in and pin 1 is the out. IF that is correct I have no signal coming out of pin 1. Does this mean the IC is stuffed???

or is there another explanation??
Thanks for any help

[petemoore]

  There's another explanation if that one doesn't work.
   To find the answer, the question must be appropriate, this requires understanding ohms law and...
  Taking voltage measurements of the IC in question to find out whether it is set up with a suitable power supply and bias arrangements...
   "Debugging" what to do when it doesn't work [sticky thread] explains in fair detail, greater detail can be studied simultaneously and separately, RG also teaches a great deal at GEO, other links are also quite applicable for learning to do IC setups [data sheet].

[Peppercorn]

I have checked the voltages but I'm just about on my last legs so I'm gunna get some sleep now! I'll post the voltages in the morning. They were all around 2-3 volts from  memory! But I'll do it right in the morning

thanks!

[MikeH]

It could be a fried IC, or perhaps there is a problem on the v+ supply and the IC is not getting power. Orrrrrrr.... it could be biased incorrectly.  Could be  few things.  If the IC is socketed you could swap it for another and see how that works.  If it's not socketed you'll want to put in a socket when you remove the old IC.

[Peppercorn]

Thanks for the help fella's

I am getting 8.99 volts at the input of the pcb and I'm using a power supply, not a battery. I don't understand what "biasing" means either! So, sorry bout that! I'm NOT dumb and I learn quick, so I won't be a waste of time if you help me!
ANYWAY.............

Here are the voltages.............
Pin 1 2.83
pin 2 2.81
pin 3 3.26
pin 4 0
pin 5 2.84
pin 6 2.84
pin 7 2.84
pin 8 2.31

Can anyone make any sense of any of that for me??

The IC is socketed! I have a few IC's a tl072 and a mn3001 and a mn3007. I bugged if I know whether I can just try and put them in or not!

Thanks in advance

[Peppercorn]

Hi again I don't know if this is relevant or not but....

I have removed the IC and these are the voltages, which are different.

pin 1 3.09
pin 2 3.16
pin 33.27
pin 4 0
pin 5 3.2
pin 6 3.2
pin 7 3.2
pin 8 8.26

Now pin 8 is reading 8.26 as opposed to 3.21.

Is that relevant?

[PRR]

Do you have the jumper-wire above the IC? Is it soldered perfectly both ends?

[Peppercorn]

Yea mate, I've checked the voltage there and it seems fine, but I am about to go and double double check it at all again!