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By: Windell (offline) on Friday, December 19 2008 @ 01:04 AM PST  
Windell

There is no switch, just two wires, joined with a twisty cap thing, so no short there.

*Great.*

So... you've got the right scale on the multimeter now, and you're measuring the voltage at pins 1 and 4 with respect to pin 11 (the middle pin on that side), right? If pin 4 (the middle pin on that side) reads 8 V, and you're sure, then you have a short circuit on your board somewhere. Verify this by checking the voltage across the pins at the power jack. So, you could have a real, physical short due to a stray wire or solder blob-- check the whole board very carefully. It's also possible that the short is internal to the chips-- if they had reverse power applied to them at some point, that could produce a short in them that would give this effect. Do you know if it's possible that something like that happened?


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By: darryllicht (offline) on Sunday, December 21 2008 @ 01:33 PM PST  
darryllicht

I checked the voltage across the power jack and it read 24. I don't think it is possible that the board had reverse power applied to it, but I'm not even sure how that would happen.

I have quadruple checked all of the solder joints and they are clean. I think that when the crazy monkey was trying to tack down one pin of the chip from the top, he might have held the iron a bit too long on the pin.


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By: Windell (offline) on Sunday, December 21 2008 @ 03:28 PM PST  
Windell

I checked the voltage across the power jack and it read 24.

Great, but this is not consistent with what you have said earlier-- If there's 24 V across the input, and the switch is on, you should also see 24 V between pins 4 and 11 of each chip. (Previously you said pin 4 was at 8 V from pin 11, not at 24 V.)

Please again measure the voltage at pin 1 and pin 4 with respect to the voltage at pin 11, and let me know what you see this time.
-Windell


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By: darryllicht (offline) on Sunday, December 21 2008 @ 06:04 PM PST  
darryllicht

Sorry I think I checked it wrong,

Looking down at the top side of the panel, there are three soldering points to the power jack: 12:00, 9:00, and 6:00. With positive (red) lead at 12:00, and the black lead at 9:00, the reading is 8V.

Is that the right way to measure it?


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By: Windell (offline) on Sunday, December 21 2008 @ 06:21 PM PST  
Windell

Looking down at the top side of the panel, there are three soldering points to the power jack: 12:00, 9:00, and 6:00. With positive (red) lead at 12:00, and the black lead at 9:00, the reading is 8V.

Is that the right way to measure it?

Yes, that's the correct way.... so you're actually seeing 8 V there, not 24, right? If that's the case, then you have definitely got a short circuit somewhere on the board. (If you were soldering the chip in "from the top" that might be a contributing factor.)


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By: darryllicht (offline) on Sunday, December 21 2008 @ 07:56 PM PST  
darryllicht

Yes, 8V

So what next? I have one or two extra chips from past orders.


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By: Windell (offline) on Monday, December 22 2008 @ 12:08 PM PST  
Windell

Unfortunately, there's no way to measure exactly where the short circuit is occurring. If you are *sure* that there's no visible short circuit on the board-- no stray solder or other wire connecting two pins that it shouldn't, the next most likely causes are (1) you've got a component in the wrong place or (2) one of your components is damaged. It could be a resistor, capacitor, or chip causing the problem-- LEDs are not likely suspects. One of the clearest signs that there's trouble in a component is that it is getting hot-- the chips, for example, should never get hot. If you do want to try removing the chip, you can, but it's possible that you won't see any improvement until all of the chips are removed, depending on where the short actually is. Once you have removed the short, you should again be able to read 24 V on the circuit; that will be your sign that it's fixed.


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By: darryllicht (offline) on Monday, December 22 2008 @ 12:39 PM PST  
darryllicht

What kind of chips should I order?


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By: Windell (offline) on Monday, December 22 2008 @ 01:12 PM PST  
Windell

If it is the chips, then type LM324N. You can get some on the garage sale page.


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By: Anonymous: issac () on Friday, May 11 2012 @ 10:03 PM PDT  
Anonymous: issac

I wanted to ask about making LED strip to be attached to cycle type and when we drive cycle it makes an image or text, how to do that?






       
   
By: Windell (offline) on Saturday, May 12 2012 @ 01:07 AM PDT  
Windell

This question does not seem relevant to the thread, or indeed to the interactive LED projects. Perhaps post this question in a different forum here, in a new thread?


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