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 Problem+solution:: Half of the LEDs stay lit up, all the time
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By: Windell (offline) on Monday, November 19 2007 @ 02:09 PM PST (Read 2694 times)  

I encountered an unusual error in one of the panels as I was testing it this weekend, so I thought that I should make a note of it:

Symptom: Half of the LED banks on the board stay on essentially all the time, no matter what. It never settles down to near zero.

Cause: One of the four op-amp chips did not have its power supply connected correctly and was interfering with the virtual-ground reference point of the whole board.

Solution: Double-check the soldering of the four chips-- pay particular attention to the middle pin on each side of each chip, which are the power supply connections. One of those, on one of the chips, had a crappy excuse for a solder joint.

Windell H. Oskay

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