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By: Anonymous: Dirk Doofusson () on Sunday, December 14 2008 @ 11:56 PM PST (Read 24105 times)  
Anonymous: Dirk Doofusson

Thank you for all of your help, answers and advice over the last year.

The last pair of panels I assembled had some leds that stayed on, but I checked the connections and fixed the issue easily. The latest one though has been more difficult.

When plugged in, D10, 12, 14, 16, & 18 light up constantly, but that is it. I have triple checked all of the connections, polarities, and resistor values, and after reading through the forums, I am worried that perhaps I fried the chip(s).

Please advise. I have a multimeter also.





       
   
By: Windell (offline) on Monday, December 15 2008 @ 12:23 AM PST  
Windell

Not sure I understand the problem clearly yet-- perhaps you can clarify this a bit.
Do you mean
(1) In all four quadrants, D10-18 (even) are stuck on, panel is otherwise off.
(2) Everything is working except for one quadrant, where D10-18 (even) are stuck on, or
(3) Nothing is working in any quadrant except for one quadrant, where D10-18 (even) are stuck on.

-Windell


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By: Anonymous: Dirk Doofusson () on Monday, December 15 2008 @ 11:50 AM PST  
Anonymous: Dirk Doofusson

Sorry,

Nothing is working in any quadrant except for quadrant four (lower right corner), where D10-18 (even) are stuck on.





       
   
By: Windell (offline) on Monday, December 15 2008 @ 01:51 PM PST  
Windell

Well.. you're right-- that doesn't sound good at all. It may be the case that your chips have been damaged. Has anything happened that would lead you to suspect that?

Please check the board power supply first:
U101 pin 1 is at 12 V
U101 pin 11 is at ground
U101 pin 4 is at 24 V


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By: Anonymous: Dirk Doofusson () on Monday, December 15 2008 @ 04:10 PM PST  
Anonymous: Dirk Doofusson

Yes, I crazy monkey soldered the chips in so that could have possibly done it.

I will check those pins tonight.





       
   
By: darryllicht (offline) on Monday, December 15 2008 @ 10:24 PM PST  
darryllicht

Ok, well ... could you please tell me how to check those pins with the multimeter. I am not quite sure how.

Gosh Oops!


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By: Windell (offline) on Monday, December 15 2008 @ 11:00 PM PST  
Windell

No problem. Smile

Set your multimeter to DC volts, with range sufficient for up to 24 V.

Pin 1 of the chip is on the end by the half-moon shape. The pins are numbered counterclockwise, starting at that pin #1, through pin #14 which is also at the end with the half-moon. Pins 4 and 11 are at the middle of the chip on opposite sides.

Touch the black (negative) point of your multimeter to pin 11, and measure the relative voltage at pins 1 and 4.


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By: darryllicht (offline) on Tuesday, December 16 2008 @ 09:13 PM PST  
darryllicht

Thank you again for the help,

I followed your directions and pin 1 showed 20V, and pin 4 showed 39V. That didn't seem possible but what do I know?


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By: Windell (offline) on Tuesday, December 16 2008 @ 11:47 PM PST  
Windell

No... that shouldn't be possible. If you're using a 24 V power supply, you should not be able to generate more than 24 V between any two points on the board. Are you sure that you're set to measure volts dc, not some other quantity?


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By: darryllicht (offline) on Wednesday, December 17 2008 @ 09:59 AM PST  
darryllicht

I must be reading it wrong. I will send photos later.


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By: darryllicht (offline) on Wednesday, December 17 2008 @ 10:17 PM PST  
darryllicht

Ok,

So thank you again for holding my hand through all of this. I uploaded the photos to flickr and put the details in the notes.

http://www.flickr.com/photos/18297379@N00/


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By: Windell (offline) on Thursday, December 18 2008 @ 12:56 AM PST  
Windell

Okay... I presume that you've checked that the battery on your multimeter is good. I suspect that you're not reading the value right. Set the scale to 50 V. Then, the reading should be read off of the scale that goes to 50. This is 8 V: http://www.flickr.com/photos/18297379@N00/3116957537/

Update:
I do see one cause for concern in your photo: It looks like you've put the switch *under* the circuit board on wires, and the switch is made of metal... and has parts at 24 V and ground. If you haven't protected the switch suitably, it could easily touch some of the metal underparts of the board there and cause a short circuit or worse.


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By: Anonymous: Debs () on Thursday, December 18 2008 @ 12:18 PM PST  
Anonymous: Debs

Hi,
I had a problem similar to this, from the sounds of it. I asked my dad who is into all the electronics stuff, and he told me to change the chips. Somehow, the chips were either faulty or i blew them up. So try changing all of the chips and see if that works. It is possible that the two panels were not plugged in correctly, if they are plugged in so they are one pin out, it might damage the chips.

Smile Hope it helps! Let us know how you get on.

Debs





       
   
By: Windell (offline) on Thursday, December 18 2008 @ 01:15 PM PST  
Windell

So try changing all of the chips and see if that works. It is possible that the two panels were not plugged in correctly, if they are plugged in so they are one pin out, it might damage the chips.

Careful with that advice! If the power supply was applied to the boards backwards, or if the boards were powered on while plugged in to each other "one pin off," the chips can get damaged and will need replacement.

Exclaimation However, *DO NOT* replace the chips unless this has happened-- We've seen a lot of cases where people have replaced the chips when there was no reason to, often causing severe damage to the board in the process. The number one cause of non-working boards is a missing or incomplete solder joint. Number two is randomly replacing components to debug the board.


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By: darryllicht (offline) on Thursday, December 18 2008 @ 07:54 PM PST  
darryllicht

Ok,

Fresh batteries and recheck pins one and four with switch at 50 reads the same as the corresponding photos I posted: pin 1= 4v, pin 4 = 8v (thanks for explaining how to read that, duh!).

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


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