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Discussion Starter #1
I recently bought a Kit 74 to use to control christmas lights. I have had trouble, but i finally got it working with the computer. Now my only problem is i am getting voltages when i should not be. When the relays are in the off positions, some of the outlets are getting anywhere from 30 volts to 110. I dont know enough about electronics to troubleshoot this, so i was wondering if anyone could hep. The instructions that came with the board said if i wanted to pull more voltage to solder heavier wires onto it, so i soldered 14 gauge wire on the bottom because thats what i had and i knew it would work. if anyone could help me that would be great!
 

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There are NC (normally closed) terminals and NO (normally open) terminals meaning, depending on how you connect you either have voltage all the time until a signal is given, OR you have no voltage until a signal is present.

Are you sure you are hooking up to the right ones, just a thought?

Don
 

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Discussion Starter #3
I do have it wired like that. When i turn the circuits on with the computer, they have 120 volts, but when i turn them off, not all of them are at 0
 

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Keeper of Spider Hill
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I do have it wired like that. When i turn the circuits on with the computer, they have 120 volts, but when i turn them off, not all of them are at 0
Have you tried unplugging the board from the computer and then test to see if any voltage is still passing ? If there is that will tell you if there is something internally wrong with any of your relays. If power drops, then your problem is coming from your controller. :)
 

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Discussion Starter #5
with the controller unhooked from the computer, i was getting the same readings as when hooked to the computer
 

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Discussion Starter #7
is there some way i could have screwed up the relays when building it, because it is brand new. But i assembled it myself
 

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Keeper of Spider Hill
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is there some way i could have screwed up the relays when building it, because it is brand new. But i assembled it myself
I would examine the contact side of the relay. Make sure none of your solder joints are touching. (I am assuming you soldered the relays in ? ) You might have a connection between your COM and NO pins on the affected relays.
 

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Discussion Starter #9
I was going to take off the wire i soldered onto the bottom and see what results i get when i do that so that i can isolate the problem.
 

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Can you post some close up pictures of your solder job?

Those contacts are pretty close together and it sounds to me like you may have a tiny bit of solder bridging the gap between the contacts.

This might be a very high resistance connection causing you to get less than 120 volts across, but still getting something.

If this is the case, it is also probably getting hot.

Whenever I want to run something that requires a lot of current from a kit 74, I use the on-board relay to drive a secondary relay with huge contacts that can handle 20 or 30 amps.

The Kit 74 turns on the big relay coil. The big relay contacts turn on your device.
 

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Discussion Starter #11
i will try to get pics on here soon. I thought about using bigger relays, but i couldnt spend that kind of money cause i'm only 19. unless i was looking at ones that were too expensive
 

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Discussion Starter #13
I think i figured out all of my problems. The low voltage wasnt enough to turn on the lights at all, so they are fine. I just have a few minor touches to finish on it. Thanks for the advise anyway!
 
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