Defective LED panel?

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effix
 
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Joined: Tue Feb 04, 2014 5:58 pm

Defective LED panel?

Post by effix »

Hello,

I ordered a group of 5 of the small 32x32 led panels (order 429936) to build a dynamic marquee for an arcade cabinet.
After prototyping the driver logic with a single panel, I connected all 5 and discovered that one of them was missing a column of red right in the middle.

Image

It seems like one of the pins (I think pin 7/out2) on RU2 (one of the driver Jxi5020 chips) is always held with an off signal. I don't see any obvious solder bridges, but the solder on that one is sloppier than the others.

Is there any possibility of a replacement?

Thanks!

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adafruit_support_mike
 
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Re: Defective LED panel?

Post by adafruit_support_mike »

Could you post a photo of the back showing the dodgy connections please?

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effix
 
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Re: Defective LED panel?

Post by effix »

Here are a couple of angles.

Up this close, that slop actually looks like if could be just flux. There is a curious column of solder coming off of pin 15 there, but doesn't seem to be in the way.

Pin 7 on the chip looks fine. However! If you follow the trace from that pin to the resister pack (RP7), the top view makes it look like there isn't any solder at all.

Image

I have confirmed that bridging that gap manually brings back the missing red leds.

It looks fixable, but I've never soldered any surface mount components before.

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pburgess
 
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Re: Defective LED panel?

Post by pburgess »

Can't quite tell...is the solder mask blocking the pad? If so, that'd need to be scraped away before soldering.

Anyway, if you'd prefer a replacement, we can do that. If you'd like to have a go at fixing the soldering to get this done sooner, go ahead and try...we'll replace the panel if that doesn't work out for you.

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effix
 
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Re: Defective LED panel?

Post by effix »

It is pretty hard to tell from my bad photography - it looks dark because that pad is perfectly flat and not catching light in the same way as the sloped ones that have solder on them.

I held my breath and went for it. It totally works now! No missing pixels.

Thank you for your time.

Image

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