Help my first build isnt working!

[petemoore]

  With the talk of learning analog meter [something that would do well to become moot exp. with the acquisition of a DMM], wires touching under the board...many other items I can think of and probably even more...
  Perhaps setting this board aside and beginning with a gain stage booster, something simple.
  anyway, for a dual oa to work...
  it's a whole lot of typing to go through, working with results which are hard to impossible to verify..
  I can't tell whether it's an 'analog misread' [I used an analog meter, but between the adjustment which it probably needed, the multi-scaled faceplate etc. I often questioned the validity of my reading of it or the indications of the meter itself.
  Adding to that, questions of grounding unfamiliarity, it could be these two hurdles' are simply too close together to be leaped over no matter how many times tried...when you don't know what to look for, deciding what to do with uncertain readings with no reference probably leaves you with a ground floating....or something else...the only thing known for certain is that it still doesn't work.
  Once you get a DMM, clip the black lead to ground point, unpowered, test that all points marked ground on the schematic, including both sleeve connections..beep.
  Then go ahead and touch everywhere else looking for stray grounds to eliminate.
  The battery clip has a ground marking too...anything marked Gnd.
  clip to the + lead of the battery clip, hear a beep at pin 8, or make that connection.
  Each equal value resistor of the voltage divider has a rail connection, one to Gnd., O.V, one to V+, where they meet, with circuit powered, 1/2v should be there.
  All pins except 4 and 8 are inputs and outputs of gain stages {IIRC this is two gain stages?], and need room to swing above and below their bias points. Say the battery is 8v, if the output of a gain stage is at 4v, it has 4v to swing toward Gnd- and V+...it's riding in the middle, and the waveform at output can and swings above and below the bias when input 'tells it to.     
  If the OA stages output were at 2v, it would have..depending on the OA requirements etc. [say it needs 1v 'padding'...it can't swing linearly all the way down to ground]...when it tries to swing toward negative it has only 1v left before the rail starts making it act funny or run out of steam...it can't swing below ground, and needs room between ground and how low the output can swing.
  Basically all the pins [except of course 4 and 8] need to be 'sorta close to the middle' for operational bias voltage.
  I tell get a DMM and suggest build a booster on perf.

[DBDbadreligion]

do you think if i just got a new perf. board and used my existing components to rebuild the circuit board i might be able to fix the issue.  and this time i would use IC sockets?  and also not put put everything so far apart from each other.

[gaussmarkov]

do you think if i just got a new perf. board and used my existing components to rebuild the circuit board i might be able to fix the issue.  and this time i would use IC sockets?  and also not put put everything so far apart from each other.

probably, but it is always possible to damage an IC, so you may need to replace that.  resistors and capacitors are
more robust.

lots of space is not the main issue.  in fact, i think you should continue to give yourself lots of space so that you have
plenty of room to work without making connections between things that should not be connected.  using IC
sockets is a great idea.  lots of people always use IC sockets, even after they have been building for a long time.

secondly, i suggest that you go slowly and try to stick to the layout.  as i mentioned above, crossing different nets
over each other is risky.  i make most of my mistakes rushing to finish because i want to hear the circuit work.  try
not to take shortcuts.    i know how hard that can be!

[DBDbadreligion]

yeah also i saw this stuff on radio shack's website.
http://www.radioshack.com/product/index.jsp?productId=2104395&cp=2032058.2032230.2032265&parentPage=family
could i just draw traces with it on the perfboard and not use the leads?  it might work better for my first time.

[gaussmarkov]

yeah also i saw this stuff on radio shack's website.
http://www.radioshack.com/product/index.jsp?productId=2104395&cp=2032058.2032230.2032265&parentPage=family
could i just draw traces with it on the perfboard and not use the leads?  it might work better for my first time.

if you search the forum for references to "circuitwriter" you will see what others have said.  the most important thing is that you cannot solder to this stuff.  so you would have to solder all of your parts onto the perfboard first, and then draw the traces afterwards.  i suggest you try it with a simpler, smaller circuit--like a booster.

alternatively, for your first project, you might consider buying a pcb made by someone else, like tonepad, generalguitargadgets, ...  then you wouldn't be drawing traces after soldering.  once you've soldered, you will be done. 

[DBDbadreligion]

ok, well i went out and got ic sockets and new op amps, i put all the compnents onto a new perf board and it is still having the same problem.  pin 4 is still getting 9V of power throughout the board, and all the grounds are too.
i think ill make a voltage divider and see what that might help with.  i just havent been able to get a DMM, because i dont have enough money.  i guess ill ask my dad to lend 30 bucks to go buy a decent one from radioshack.

[DBDbadreligion]

is this how the voltage divider should look?

battery (+) ----R1----- battery (-) ----R2----- ground

[gaussmarkov]

ok, well i went out and got ic sockets and new op amps, i put all the compnents onto a new perf board and it is still having the same problem.  pin 4 is still getting 9V of power throughout the board, and all the grounds are too.
i think ill make a voltage divider and see what that might help with.  i just havent been able to get a DMM, because i dont have enough money.  i guess ill ask my dad to lend 30 bucks to go buy a decent one from radioshack.

now that is really disappointing.  i have a feeling there is something simple, an assumption or an understanding, that is messing this up.  do you want to mail your builds to me and i will look them over?  it probably won't cost more than your time and a couple of bucks.  i will send them back fixed, with explanations.

[DBDbadreligion]

yeah that might be the easiest thing, are you sure you can surly fix it?

[gaussmarkov]

yeah that might be the easiest thing, are you sure you can surly fix it?

yep.  i'll send you an email. 

[DBDbadreligion]

alright i sent u a PM

[mattpocket]

I bet this is something really simple...

Let us know what it was!? 

Matt