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 2nd Panel Problem Panel.
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By: xDGx (offline) on Wednesday, February 24 2010 @ 01:37 PM PST (Read 4262 times)  
xDGx

After assembling my first Interactive LED Table, I decided to assemble some more...
After finishing the second board and pluging it to the first one (which works fine), I noticed 2 problems, and even after checking some solder joints the problems persist.
I'll try to be as clear as possible for fast/best troubleshoot Smile

The problem is:
Scenario: 2 boards (one working, other almost working lol) - Regulated 24V, 2A power supply.
The first panel ALWAYS WORK. The problem is only on the second panel (no switch or plug on the second one).

Switched connectors (male and female, both sides), no luck.

LED Locations D110 D112 D114 D116 D118 *never* light up.

When the ROOM lights are OFF, the whole panel is dim, apart from the LEDs that don't light up, but it seems like it captures movement as the "water effect" is working, but very dim compared to the neighbor panel.

When turning the room lights ON, the LEDs light up normally (very bright) and both panels work the same apart from the LED locations mentioned above that never light up. I could almost live with that but the 5 LEDs that are off kinda kills the effect.

Looks like the problem is on the 1st quadrant so I've tried replacing the IC but no luck either.

Unfortunately, I'm (still) a graduate evil mad scientist and can't fix it. Help ? Thank you very much in advance..


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By: Windell (offline) on Wednesday, February 24 2010 @ 02:10 PM PST  
Windell

Is there more than one issue here? I'm not sure that I fully understand your question-- I can't tell if you're describing several different things or if it's just that those 5 LEDs do not light up. If there are additional issues, it would be *very* helpful if you could phrase each one as a single question.

* For the five LEDs that aren't lighting up: A problem at any one of those five locations would cause this, and there are no other component locations that can cause this. Likely causes include a flaky solder joint at one of these places, a backwards LED, or an LED damaged by lead bending or heat. Try touching up all five locations. If there's still no response, flip the boards over, and turn on the power. Then *carefully* touch an LED across each location on the back side. Long lead to square pad as usual. If the LED lights up in any one of those five locations, mark it to indicate which LED needs replacement.

* I'm not sure why you were switching connectors. I don't see any reason to suspect that the connectors were causing a problem and if you mean that you *desoldered and swapped them,* let me assert that preemptive desoldering is a *bad* idea.

* I can't tell what you're asking about with respect to the "idle" level of the boards. This could be about the idle setpoint or perhaps about the LED brightness itself.
-- Is this panel from a different batch than your old one? We match LEDs per kit, but there are always batch to batch variations between white LED lots.
-- If it's a true *setpoint* issue, as though there's a significant bias in each quadrant as to which sets of five are brighter, it's possible to tune that by adjusting one resistor value slightly.
-- If you're trying to match two panels exactly in every respect, it's possible to drive yourself insane this way.


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By: xDGx (offline) on Monday, March 08 2010 @ 01:14 PM PST  
xDGx

I still have more panels to solder and had problems with more than one board, so I'll post a video of the issues when I'm done. The problems must be caused by bad solder joints somewhere, which makes me wonder if I could use a "solder bath" to avoid hand soldering and finish the boards faster. BUT, I have no clue of what I'm talking about. Is that even viable ?
Thank you Smile


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By: Windell (offline) on Monday, March 08 2010 @ 01:49 PM PST  
Windell

Yes, there are solder baths that can be used for bulk soldering; this is one of several high-throughput methods used for mass production of boards with through-hole parts. However, it's probably not nearly worth the effort for just a few boards. I'd suggest instead spending your time learning to identify good and bad solder joints by appearance; it's usually pretty quick to scan a board for potential issues once you have that skill.


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By: xDGx (offline) on Wednesday, March 24 2010 @ 02:29 PM PDT  
xDGx

Quote by: xDGx

After assembling my first Interactive LED Table, I decided to assemble some more...
After finishing the second board and pluging it to the first one (which works fine), I noticed 2 problems, and even after checking some solder joints the problems persist.
I'll try to be as clear as possible for fast/best troubleshoot Smile

The problem is:
Scenario: 2 boards (one working, other almost working lol) - Regulated 24V, 2A power supply.
The first panel ALWAYS WORK. The problem is only on the second panel (no switch or plug on the second one).

Switched connectors (male and female, both sides), no luck.

LED Locations D110 D112 D114 D116 D118 *never* light up.

When the ROOM lights are OFF, the whole panel is dim, apart from the LEDs that don't light up, but it seems like it captures movement as the "water effect" is working, but very dim compared to the neighbor panel.

When turning the room lights ON, the LEDs light up normally (very bright) and both panels work the same apart from the LED locations mentioned above that never light up. I could almost live with that but the 5 LEDs that are off kinda kills the effect.

Looks like the problem is on the 1st quadrant so I've tried replacing the IC but no luck either.

Unfortunately, I'm (still) a graduate evil mad scientist and can't fix it. Help ? Thank you very much in advance..




I've returned to that board that's not working properly and recorded a video of the whole thing... help appreciated, thank you in advance.

http://www.flickr.com/photos/xdgx/4460238983/


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By: Windell (offline) on Wednesday, March 24 2010 @ 03:28 PM PDT  
Windell

It's a little hard to see what's going on the video, but it looks like the left panel is simply not very responsive in the dark, but is working fine when the room lights are on. Is that correct?

If so, it indicates that the active IR is not working correctly. Check the soldering at the eight IR LEDs and resistors R215, R315, and R415. If you happen to have a voltmeter handy, you could also measure the voltage across each IR LED; they should be at about 1.25 V, each.


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