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PostPosted: 29.09.2008 15:04 
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Junior Modder
Junior Modder

Joined: 16.07.2008 17:44
Posts: 6
Hi!
I built that ColorFade but the led seems only shine all the time..tried also to put trimmer before transistor base but no effort, it makes led darker but no any fading effect. I have check the wires sure tens of times but cant see any mistake.. :|

I took photos of PCB both sides and put them together with photoshop. Maybe it tells more.
http://koti.mbnet.fi/petex/colorfade.jpg

Can anybody help me with this?
Thanks!


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PostPosted: 29.09.2008 16:24 
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Site Admin
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Joined: 24.01.2002 10:09
Posts: 4683
Location: Finland
Can't find any wiring errors... There are some key issues that people have had with this circuit that you might want to check. Some people had a dry electrolytic capacitor. Few people have had a deal LM324 chip. One major issue have been a poor quality wall transformer. You need a stable voltage for timing to work properly. Try the circuit with a battery for example.


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PostPosted: 29.09.2008 18:20 
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Junior Modder
Junior Modder

Joined: 16.07.2008 17:44
Posts: 6
Yeap, I have tested with battery and 2 different capasitors..maybe I have to check the chip next.


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PostPosted: 02.10.2008 19:34 
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Junior Modder
Junior Modder

Joined: 16.07.2008 17:44
Posts: 6
Now tested with another LM324N and ceramic condensator but same fault again. Maybe I have to take this to school and test with oscilloscope :twisted:


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PostPosted: 05.10.2008 06:11 
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Regular Modder
Regular Modder

Joined: 26.05.2007 10:06
Posts: 128
Location: Texas
I think its GREAT how you used an image as you did to help explain how it is wired. I still may not understand it completely, BUT I am getting closer because of images like yours along with the schematic. When you do find out what it was, PLEASE update us. I would really like to know.


Dan


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PostPosted: 05.10.2008 12:39 
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Regular Modder
Regular Modder

Joined: 02.11.2006 19:30
Posts: 249
Hmmm. Is collector of bc548b connected to pin 11 (witch is connected to ground) of lm324? For me it looks like it should be connected to pin 4 (wich is connected +5V) instead of pin 11. It might be that I understood wrong, but I'm 90% sure that transistor is connected wrong.


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PostPosted: 06.10.2008 15:55 
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Junior Modder
Junior Modder

Joined: 16.07.2008 17:44
Posts: 6
:idea: BIG THANKS!!
*banging my head to the wall* ..the problem was that NPN-transistor. I put PNP instead of it and it works now :)


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