DiyLightAnimation

Hardware => Lynx Express => Topic started by: Kappa2006 on November 21, 2011,

Title: 3.3v led not lit
Post by: Kappa2006 on November 21, 2011,

I plugged my LE in for the first time tonight, with no chips installed.  The 5v light is lit but the 3.3v light is not.  LED orientation is good, and I've gone over the board touched up some solder joints with no luck.  I measured voltage at the inop led and I have 2.4 volts, compared to 3.5volts at the working led.  Any suggestions on where to look next?  Thanks.

Brian

Title: Re: 3.3v led not lit
Post by: deplanche on November 21, 2011,

Check the numbers on the voltage regulators and make sure they are correct.  That was my problem last year.  Sometimes the parts you get aren't the parts that you are supposed to get.

Title: Re: 3.3v led not lit
Post by: combustionmark on November 22, 2011,

Also check board for solder bridges, You may have shorted the 3.3v regulator. May be a bad 3.3V chip or a bad led. Measure the resistance across pins 27, 28 of the pic24 chip, If it is not shorted turn on the express and measure the voltage, if you have 3.3V should be OK. 28 is the +

Good Luck