Nothin’s working

[Victastic]

I just put together one of your Defusable Clocks and when I plugged it in nothing happens. The VCC gets hot pretty quickly. I have read all the other threads referring to this problem and I am still having issues. I checked this thread viewtopic.php?f=34&t=2486 and I get continuity on all the points I also have resistance between the two right most pins on the VCC. I cannot seem to find where there may be a short. I have resoldered all the components and I am still having problems. Any ideas?

Here is a pic of the back of the board. I didn’t want to compress the photo so I gave a link instead of embeding it to the thread
http://i.imgur.com/a8YLV.jpg

thanks
Chris

[Michael]

Some questions that may help:

What type of power supply are you using? Is it center-positive?

If the voltage regulator is hot, then polarity is reversed or there is a short between GND and VCC. But it sounds like you have resistance between them.

Are the two electrolytic capacitors oriented correctly?

Are you sure you have the 74LS247 and 74HC595 chips in the right position and oriented properly? Soldering on the back looks good.

[Victastic]

@Michael wrote:

Some questions that may help:
What type of power supply are you using? Is it center-positive?

ugh… lol that was it. I didn’t even think that it could’ve been the power supply. I am happy to say, now, that with the correct power supply everything is working just fine.

thank you so much
Chris

[Michael]

Excellent! You are lucky you didn’t fry that voltage regulator!

[Author]

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