Author Topic: Power/Wiring problem I keep having  (Read 2798 times)

Matmosphere

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Re: Power/Wiring problem I keep having
« Reply #15 on: July 31, 2016, 04:54:03 PM »
Agreed, that kinda stuff happens to everybody. I know it's happened to me before as well. Definitely don't get discouraged though, this is a fun hobby, the more you build the smoother things will start going. It might help to build a testing rig like the one Brian just posted a tutorial for. If you plan on sticking with this it's definitely worth dropping ten bucks into a testing rig, makes life much easier in the end.

galaxiex

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Re: Power/Wiring problem I keep having
« Reply #16 on: July 31, 2016, 05:18:35 PM »
Ya, I've done everything from inserting an I/C backwards, to wiring up power leads backwards, jacks installed wrong etc.

It happens, we're not perfect, and we certainly weren't born knowing this stuff.

Biggest thing for me, is to not work tired/distracted or hungry.

The other thing is to not get cocky.

The following happens when I'm any of the above.....

"I've built dozens of pedals!"
"I know what I'm doing!"
"I couldn't have made a mistake!"

Yes, I'm guilty of all those.... it's a humbling experience.

The other thing that happens is, looking at something and not realizing that it is indeed, installed backwards....
... for whatever reason, you just don't "see" it.

"i put that in there.... It's gotta be right!"   

Ha! It don't gotta be anything....
Fear leads to Anger, Anger leads to Hate, Hate leads to Suffering.

olejason

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Re: Power/Wiring problem I keep having
« Reply #17 on: July 31, 2016, 05:50:40 PM »
Thanks for the words of encouragement everyone, I've managed to not get too frustrated with this one.  I tinker for awhile and then take a break.  I don't mind the troubleshooting as long as I feel like I'm making a bit of progress here and there  ;D

The TL074 IC does have a notch, sorry I should have noticed it was cropped out in those pictures.  I wasn't sure if the dot or notch took precedence so I tried the IC both ways just to be sure.  Below is a better picture of the IC & component side of the board and a picture of how I have everything breadboarded.  The red lead connected to ground is my input/output jacks.  None of the wires in the middle rows are connected to the PCB.  If I disconnect power and ground to the PCB I do get a guitar signal through the amp so the wiring appears to be okay.





galaxiex

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Re: Power/Wiring problem I keep having
« Reply #18 on: July 31, 2016, 06:10:01 PM »
................. I wasn't sure if the dot or notch took precedence so I tried the IC both ways just to be sure.  ...........

If the TL074 was installed backwards and powered up, it's a given that it fried.

Do you have a spare?
Fear leads to Anger, Anger leads to Hate, Hate leads to Suffering.

olejason

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Re: Power/Wiring problem I keep having
« Reply #19 on: July 31, 2016, 06:25:27 PM »
Oh wow, I definitely fried it then.  Unfortunately I don't have a spare but I'll order one now.  I don't recall how the IC was oriented when I first applied power but it very well could have been wrong at that point.  Would a bad IC explain all the weird oscillation noises and stuff when I jiggle it?

galaxiex

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Re: Power/Wiring problem I keep having
« Reply #20 on: July 31, 2016, 06:30:50 PM »
...........  Would a bad IC explain all the weird oscillation noises and stuff when I jiggle it?

Very likely.
Fear leads to Anger, Anger leads to Hate, Hate leads to Suffering.

BrianS

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Re: Power/Wiring problem I keep having
« Reply #21 on: July 31, 2016, 08:44:03 PM »
Pm'ing your address and I will send one to you tomorrow in the mail if you would like. I have an extra one you can have. 

olejason

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Re: Power/Wiring problem I keep having
« Reply #22 on: July 31, 2016, 08:58:29 PM »
Thank you Brian that is very kind of you, I went ahead and ordered a few earlier though since I needed some other parts as well.  They should be here this week and I'll update the thread... hopefully this will solve the mystery :)  Thanks again to everyone who has offered assistance.

olejason

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Re: Power/Wiring problem I keep having
« Reply #23 on: August 08, 2016, 05:15:10 PM »
I received the replacement chips today but unfortunately I still don't get any audio when power is supplied to the PCB.  I was very careful to have both IC's seated in the sockets before connecting the battery for the first time.  Is there anything else you'd recommend trying?  I'm not real sure where to go from here.  I'm getting power throughout the circuit but I don't really know what kind of values I should be looking for.  If I turn the amp up quite a bit I can hear a little hiss coming through and it is affected by turning the pots.  Thanks all, I appreciate your help.


davent

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Re: Power/Wiring problem I keep having
« Reply #24 on: August 08, 2016, 06:20:10 PM »
I'm sure someone's mentioned but i haven't gone back through, an audio probe to trace the guitar signal through the circuit to pinpoint where exactly it disappears.

http://www.diystompboxes.com/pedals/debug.html

dave
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If my photos are missing again... they're hosted by photobucket... and as of 06/2017 being held hostage... to be continued?

olejason

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Re: Power/Wiring problem I keep having
« Reply #25 on: August 08, 2016, 09:34:32 PM »
Thanks!  The audio probe is helping.  I actually had a transistor with a wrong pinout in Q3.  Now that is sorted and I traced to IC1 and can still hear the clipped signal going through D1, D2, D3 up to C8 but then I lose it.  It also seems to be draining the battery rather quickly, maybe I should use an adapter for power for now?  It's late so I'll resume tomorrow. 

Bizarrely enough, the complete circuit passed signal for a moment after I changed the transistor.  I thought "Hey it's fixed" and went about hooking up the output to my amp.  Then it didn't work  ;D

Jules

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Re: Power/Wiring problem I keep having
« Reply #26 on: August 09, 2016, 11:14:02 PM »
Reflowing the solder pads often helps. It looks like you have a few points there that could do with a bit more solder too.

olejason

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Re: Power/Wiring problem I keep having
« Reply #27 on: August 10, 2016, 08:04:36 AM »
It works!  Hooking up an adapter to the breadboard seemed to do the final trick.  My battery was still reading around 8v but I guess the circuit was dropping it too far to power the IC's.  Someone mentioned that could be an issue a few posts back.

Thanks to everyone for all the help, setting up an audio probe will make all of this troubleshooting much easier in the future.

devilsnight

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Re: Power/Wiring problem I keep having
« Reply #28 on: August 11, 2016, 12:29:47 AM »
Have you tried a brand new battery here?? Your last post you were measuring 7.62v unloaded. That seems unusually low to me. I throw out my 9 volts if they have less than 8.8 volts. A new 9 volt should read closer to 9.5 volts. You have to take into account also how much current your circuit is going to draw.. One reason I don't bother using batteries in the pedals I build. 

doh! Didn't see page 2! Good to see you got this working
« Last Edit: August 11, 2016, 12:36:23 AM by devilsnight »