guizmo Posted May 13, 2010 Report Share Posted May 13, 2010 Hi, this is my very first post on this forum, so I hope someone will kindly answer my question.I'm building the Darkroom timer found on this site. I have made the circuit on my breadboard and everything works very well. So I'm making the first part, the display unit. Just for your information I make my own PCB.That's where my problem is !!!! I'm loosing my mind here ....Let say I have the number zero displayed on all 4 LEDS, the letter D, E don't light up on LED 1 but the other 3 LEDS are ok ???? Sometime letter C of LED 1 2 3 is barely visible but LED 4 is ok ???? That goes for other numbers too !!!!And before you ask, none of the 7-segment of the LEDS are burned because I can switch the LED is any position, they are mounted on 20 pins dip socket that I cut.Thanks for your answers. Quote Link to comment Share on other sites More sharing options...
guizmo Posted May 16, 2010 Author Report Share Posted May 16, 2010 Problem solved, I made sure that they were no more flux between pads !!!!!Did not know that flux could do that but anyway that's the only thing I did and it is working well now !!!! Go figure it out ??? ......... Quote Link to comment Share on other sites More sharing options...
mendimano Posted June 12, 2010 Report Share Posted June 12, 2010 Hey Guizmo how did yu removed the flux?? :D Quote Link to comment Share on other sites More sharing options...
KMoffett Posted June 20, 2010 Report Share Posted June 20, 2010 Flux , except in extremely high impedance circuits like pH meter inputs, should not cause a problem. Years ago I read in an H-P service bulletin concerning field repairs to PCBs, that unless "all" flux can be removed (think in-factory process) it should be left in place. Ken Quote Link to comment Share on other sites More sharing options...
Hero999 Posted June 20, 2010 Report Share Posted June 20, 2010 I generally try to remove as much flux as possible because it looks better and I've heard stories about it attacking copper in moist environments. Quote Link to comment Share on other sites More sharing options...
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