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DIY Stompboxes => Building your own stompbox => Topic started by: deadastronaut on July 09, 2011, 07:52:38 AM

Title: HELP!...with an lfo!!!!!.....
Post by: deadastronaut on July 09, 2011, 07:52:38 AM
right ive built this lfo as part of a circuit onto pcb...twice!..and both times it just wont flash the led.

it all works fine on the breadboard..nice slow and fast pulsing...but as soon as i put it on pcb it wont have it...

heres the schematic....which works fine!..
(http://dl.dropbox.com/u/7464107/LFOBITCHSCHEMO.jpg)

and heres the pcb layout lfo part...( i isolated all the relevant lfo parts..)

(http://dl.dropbox.com/u/7464107/LFOBITCH.jpg)

heres my numbers for the op amp..tlo72.

p1  8.46 - 133  up n down...
p2  5.72 - 3.59 up n down..
p3  5.84 - 3.47  up n down
p4    0.00
p5  5.44 - 3.90  up n down
p6  5.44 - 3.90  up n down
p7  5.44- 390   up n down
p8  9.09......

so its definately oscillating on the ic, just not doing it with the leds....can anyone spot an error in the pcb conversion...i'm losing it with this @#$%ing  lfo!... :icon_evil:

thanks in advance for any help...rob.  (speed pot is 470kb. btw...)
Title: Re: HELP!...with an lfo!!!!!.....
Post by: deadastronaut on July 09, 2011, 09:25:51 AM


whooohooo......got it working....nice n quiet too.....


i had an end of another bloody resistor touching another... :icon_redface: :icon_redface: :icon_redface:  @#$%er... :icon_mrgreen:
Title: Re: HELP!...with an lfo!!!!!.....
Post by: newfish on July 09, 2011, 02:40:15 PM
...so you're building another Trem then?   :icon_cool:

Title: Re: HELP!...with an lfo!!!!!.....
Post by: deadastronaut on July 09, 2011, 02:45:37 PM
nope!... :icon_wink:

this..verified today...whooo hooo.... :icon_cool:

http://www.diystompboxes.com/smfforum/index.php?topic=88582.msg792803#msg792803


but yeah its a much better lfo....noiseless... :icon_mrgreen:
Title: Re: HELP!...with an lfo!!!!!.....
Post by: newfish on July 10, 2011, 09:39:02 AM
WOW!

That's insane!

Congratulations - here's your straightjacket...  :icon_twisted:
Title: Re: HELP!...with an lfo!!!!!.....
Post by: deadastronaut on July 10, 2011, 03:24:12 PM
^ ha ha, yeah i need one now!!!.... :icon_mrgreen: