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 Peggy 2.3 problem: D16 to D24 are darker (updated)
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By: Windell (offline) on Wednesday, May 26 2010 @ 11:01 PM PDT  
Windell

>I do not know what is the P2 option

That's the "Peggy 2" mode-- standard, as you call it. I really like your header system for switching between the two modes.

Okay-- works with white LEDs and batteries, but not with 5 V power supply. Batteries have higher short-term current sourcing ability, and there's less load on the chips. Not sure which the problem is. Maybe the power/ground connections to the second chip are inadequate... or maybe it needs a bigger decoupling capacitor nearby. Do you happen to have extra caps on hand that you could try adding there? I don't think that this means that the chips are overloaded-- because when they have problems, the problems *lessen* as they heat up.


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By: tof (offline) on Thursday, May 27 2010 @ 12:06 PM PDT  
tof

Ok, I tried a bunch of capacitors connected (by pressing with my fingers, I did not solder anything) between pins 1 (GND) and 24 (VDD) of U5.

0.1uF changed things a little bit, but from 1uF up to 100uF the problem seems to be solved! What final value do you suggest? And should I solder the capacitor directly to the chip?


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By: Windell (offline) on Thursday, May 27 2010 @ 05:35 PM PDT  
Windell

Well that's fantastic news. I think that there's a default 0.1 uF cap by that chip, so we should switch that out with a 1 uF, maybe.

Is anyone else with the same issue following this discussion?


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By: Anonymous: project2501 () on Monday, June 21 2010 @ 06:55 PM PDT  
Anonymous: project2501

Hi Windell,

I have been AWOL for a while because I have been busy with work....

I will try a 1uF and 100uF cap there this week and let you know if it solves my board's issues. Note that I was experiencing issues w/ batteries while tof was using wall power, hopefully my issue is the same.





       
   
By: Anonymous: project2501 () on Monday, June 21 2010 @ 07:25 PM PDT  
Anonymous: project2501

One question before I start... should I remove the 0.1uF capacitor at C10 and replace it with a 1uF cap? Or just solder a 1uF cap across pins 1 and 24 on U5?





       
   
By: Windell (offline) on Monday, June 21 2010 @ 07:31 PM PDT  
Windell

If you can confirm that this fixes the issue for us, that would be *very* helpful to us-- if so we'll make a change to the kit BOM.

It's up to you whether to remove the 0.1 uF cap; it won't hurt to leave it there, so it's largely a matter of whether you like to desolder and/or object to an extra cap stretching across your board. You can also temporarily add the cap directly in parallel: across the pins of the 0.1 uF cap.


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By: Anonymous: project2501 () on Thursday, June 24 2010 @ 01:41 PM PDT  
Anonymous: project2501

I soldered in a 1uF cap with the 0.1uF cap at C10 and the problem is fixed. I am using batteries.

It took a while but I am glad it is fixed, thanks Smile





       
   



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