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 Bulbdial for Xmas | problems with assembly
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By: Anonymous: Dan Mandle () on Sunday, December 26 2010 @ 08:47 PM PST (Read 4297 times)  
Anonymous: Dan Mandle

So I finally got a Bulbdial for Xmas. I have all of the blue PCB assembled and I'm testing it. The problem is that LED # d21, d26, d25, d24, d24, d62, d52, d42, d32, and d12 are not lighting. After looking at (and trying to understand) the schematics I've determined that it's "channel" LED 2:1 and pin 23 out of the microcontroller. It goes through resister R2 which I thought might be bad so I removed and replaced that with no luck. I don't have a multimeter now, but I'm going to try to borrow a friend's tomorrow. Any idea of what the issue might be? And yes, I've double and tripple checked the quality of the solders.
http://danmandle.com/bulbdial/mov.mov
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By: Windell (offline) on Sunday, December 26 2010 @ 11:57 PM PST  
Windell

Probably not related, but you should put something in location R8.

There are two likely causes of the problem. Either there's no electrical connection from the chip through R2 to the LED ring, or there's a short circuit from the "channel" to somewhere else. You could check both of those easily with a multimeter.

The relevant solder connections do not look particularly clean, to be fair. There's probably a good connection there, but I'd touch up the two connections at R2 to be sure, and check with the multimeter when you get it.

Again, it could also be a short circuit. It's probably not a connection between two of the LED pins, or there would be more LEDs out than just those connected to signal 2. Could also be a short circuit at the pins of the chip-- accidental solder blobs can sometimes do that. But, your best bet at this point is to see if you can verify continuity -- i.e., the resistance from the chip to the LEDs --and check for short circuits using the multimeter.


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By: Anonymous: Dan Mandle () on Monday, December 27 2010 @ 06:31 AM PST  
Anonymous: Dan Mandle

Wow, thanks for the quick reply!

What should go into R8? I thought you only put something there if you have a monochromatic clock?





       
   
By: Windell (offline) on Monday, December 27 2010 @ 09:32 AM PST  
Windell

What should go into R8? I thought you only put something there if you have a monochromatic clock?

Step 6 says to install 24 ohm resistors in R1-R9. That range normally includes R8. Wink


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By: Anonymous: Dan Mandle () on Monday, December 27 2010 @ 10:16 AM PST  
Anonymous: Dan Mandle

Quote by: Windell

What should go into R8? I thought you only put something there if you have a monochromatic clock?

Step 6 says to install 24 ohm resistors in R1-R9. That range normally includes R8. Wink



So it does! I installed the resister there but that didn't make a difference. I will investigate with a multimeter and will update with my findings.





       
   
By: Anonymous: Dan Mandle () on Monday, December 27 2010 @ 11:19 AM PST  
Anonymous: Dan Mandle

So in my infinite stupidity, one of the pins to the microcontroller didn't have proper solder. My friend bent the pin over and it worked great. Will add more solder when I get home. That should solve it!

Thanks for your quick responses and sorry for my stupidity!





       
   
By: Windell (offline) on Monday, December 27 2010 @ 01:49 PM PST  
Windell

No reason to assume any stupidity here-- things happen. Please let us know how it all works out, or if you need more help after the next step.


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