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Clock Kit worked but now don't work...
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Clock Kit worked but now don't work...

by tlavite on Fri Sep 18, 2009 5:31 pm

First off ive assembled lots of kits and built many electronic projects so I'm not "new" to this... I built the kit and did all of the testing along the way and everything was fine. I have nice clean solder joints and no solder bridges.. Anyway when assembling the kit i got to the step where you solder the tube insert the boost converter and then test the clock to see if it comes on, and it did come on it beeped came on and dissplayed the numbers. I removed the power supply and soldered the battery holder, diode, and buttons in. Assembled the case and pluged in the clock.... nothing happened no beep or anything. I unplugged it and took the case apart plugged in the clock and tested the regulator and got nothing no 12v no 5v i tested the power adaptor and got 13.9v. Also i noticed that the fuse gets warm now when plugged in... for some reason the fuse seems to be doing its job and not allowing the power to the rest of the circuit. I can not figure out what is wrong. It worked and now no longer works.
Attachments
DSC_0015.jpg
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Re: Clock Kit worked but now don't work...

by adafruit on Fri Sep 18, 2009 6:01 pm

you probably want to take a photo from the top
also, take a much larger photo, no details are visible here
obviously, there is a short and the fuse is protecting the circuitry (thats what fuses do)
until you remove the short, you will not be able to see any voltage on the regulator
since it worked BEFORE the last parts were put in, it is clear where you should start looking

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Re: Clock Kit worked but now don't work...

by tlavite on Fri Sep 18, 2009 6:19 pm

Yeah i figured that lol... ill also include an external link to a larger version of the picture. Also as another note the included power supply says 9v 200mA output. I am getting 13.72v out of the supply... is that correct? I have looked up and down the board for solder bridges and get nothing. I have even compared pictures from the instructions to my board to make sure everything looks fine... like i said it worked fine before i installed the buttons, switch, the batteries diode and the battery.


Bigger picture (bottom)
http://i81.photobucket.com/albums/j208/ ... C_0029.jpg

Bigger picture (top)
http://i81.photobucket.com/albums/j208/ ... C_0017.jpg
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Re: Clock Kit worked but now don't work...

by tlavite on Fri Sep 18, 2009 6:46 pm

IDK where the short is.... could the fuse have done burned itself... open? idk how that type of fuse operates but i am sure it has a failure point right? where it will just fail and keep the circuit open so nothing get through. Is it possible that the short may no longer exist but the fuse is now burned up? because i have no solder bridges at all... i have even removed the parts that where installed after it worked and still nothing.
tlavite
 
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Re: Clock Kit worked but now don't work...

by mpeg2 on Fri Sep 18, 2009 6:59 pm

Sounds like the fuse blew - with it open, there's no voltage going to the regulator, so nothing for the rest of the circuit - although I'm not sure why its getting warm.

I think you need to look very carefully at the parts you installed in the last step - working OK before, fuse blown after - therefore something is wrong with them. Look for a short...

Can't really tell anything from the pictures, too low of a magnification...

Rich
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Re: Clock Kit worked but now don't work...

by tlavite on Fri Sep 18, 2009 7:08 pm

I know the pictures are ridiculous lol i have gone over every part i can not find a short anywhere... idk what to do.
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Re: Clock Kit worked but now don't work...

by hinermad on Fri Sep 18, 2009 7:41 pm

I haven't built the clock but I've built lots of other failed kits. A couple of things you can prove me wrong on:

1) In the bottom view, there's a pad to the right of center that looks like it might be bridged to the trace running just to the right of it, or maybe to the ground plane above it. It looks like it might be one of the pads for the diode behind the battery holder, the pad nearer to the middle of the board. It might be just a trick of the light though.

2) Is the diode in backwards?

3) If the fuse is getting hot I'd suspect something (a short circuit) is trying to draw too much current through it. These kinds of fuses don't blow open like a traditional fuse, they're temperature-sensitive resistors. If you draw too much current they heat up, increasing their resistance and decreasing the current to a safe level. If you clear the short or turn off the power and allow them to cool down they return to normal. Self-resetting, in other words.

4) Is the battery holder touching anything nearby on top of the board?

Dave

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Re: Clock Kit worked but now don't work...

by tlavite on Fri Sep 18, 2009 7:45 pm

Thanks for the reply... i see what your saying in the picture... its not on my board no more it was a piece of solder but it was just sitting there. Ive sat here for about an hour staring at the board every solder connection every part... everything is in correctly the diodes are in correctly... idk... like i said it worked before installing the last few parts after they were installed it would not power on... i then removed them parts and tried again to no success. idk... is the power adaptor that comes with the kit suppose to put out 13.73 volts?
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Re: Clock Kit worked but now don't work...

by adafruit on Fri Sep 18, 2009 9:12 pm

the diode on the coin holder is shorting against it

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Re: Clock Kit worked but now don't work...

by tlavite on Fri Sep 18, 2009 11:40 pm

I thought the same exact thing.. i took it out and still the same results...
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Re: Clock Kit worked but now don't work...

by adafruit on Fri Sep 18, 2009 11:46 pm

remove all the last few things you added, until it starts working?

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Re: Clock Kit worked but now don't work...

by tlavite on Sat Sep 19, 2009 12:16 am

I'm trying that again right now. I think ceramic capacitor C5 might have been shorting against diode D5.
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Re: Clock Kit worked but now don't work...

by tlavite on Sat Sep 19, 2009 12:33 am

Okay well i removed the capacitor and placed it again i know its not touching now but it is still not coming on.... if its not a short... what are the other possibilities? is the power supply suppose to be putting out 13 volts?
tlavite
 
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Re: Clock Kit worked but now don't work...

by tlavite on Sat Sep 19, 2009 1:27 am

I just went through every part, every pin, and every single solder joint on the entire board... i went through the entire instructions around 3 times and gone over every part checked the placements and everything is correct... I can't find a single short anywhere... the fuse just continues to heat up... i am just at such a loss i have never had such a problem with a project lol and to think i am going to school to be an electrical technician lol is there any part that could have in some way gone bad that could be causing the fuse to open?

When i first tested the tube i forgot to put in the transistor by the alarm on off switch... after i turned off the clock i installed that transistor.. but i do not think that would have caused any problem since it is to turn off tube for power save mode.


Also am i suppose to have an R4 by the inductor and pizo speaker? also what is the CT1 thing the two open pins next to the pizo?
tlavite
 
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Re: Clock Kit worked but now don't work...

by ki4mmm on Sat Sep 19, 2009 7:26 am

Did you check for solder bridges *on top* of the board? There is quite a bit of solder coming through several holes in what is visible in the picture - how about at the legs of the transistor, or the other parts that went on when the problem manifested itself?
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Please be positive and constructive with your questions and comments.