AV Cabinet cooling. Build thread.

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91 posts

Master Geek

#401464 7-Nov-2010 20:39

So got it all wired up to the relay and back in the cabinet.....It all works perfectly. But as you probably guessed there a tad loud.....Thinking of wiring in a potentiometer just so I can ease the speed of the fans back....But where would I wire this in?....After the relay but before the fans?... Is a pot the best way to control fan speed?..

timmmay

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#401488 7-Nov-2010 21:59

I just used a variable voltage power supply, it works well. The fans do make a bit of a noise at 12V, but if you run them at 6-7V they put through enough air and are almost silent. The only noise is from the air itself moving.

I've spent almost my entire weekend buying, wiring, cutting, etc, and while i'm mostly done i'm not quite there. I made a little box with USB in, 5-12V in, a manual override switch on top, and plugs for the fans to go into. It works great when it's manually switched on, and keeps things nicely cool. The problem is the USB detection bit just doesn't work - there's a problem with my SSD or the wiring.

I wired my SSD (this one, with specs here) in, USB power 5V input (polarity is correct), and put power and a fan on the output in series (ie positive power to one output leg, fan to the other, then completed the circuit). The problem is the fan always runs, and never turns off, regardless of the input or lack thereof. The little LED on the relay never turns on either. I've tried all the various polarities, no change.

Anyone have any suggestion about what's going on? Could it be faulty? Am I doing something stupid? This is really, really basic stuff, I can't believe it's not working.

richms

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#401494 7-Nov-2010 22:22

Haave you checked that you have 5v across the input of the relay with a meter at all?

Richard rich.ms

timmmay

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#401497 7-Nov-2010 22:26

Yep, it's about 5.2V from the USB cable connected to the TV - the specs say 4-6V is the required input.

When I apply 4.5 or 6V across the same input with a power supply the light doesn't come on on the SSR, but I don't know if that's a "input present" or "output circuit running" indicator.

After the correct polarity didn't work I tried reversing it. No change. It's like it's hard wired on. Either that or i'm doing something stupid, but I spent an hour on it and I did electronics up to 2nd year at uni, so I should be able to figure out a relay!

richms

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#401501 7-Nov-2010 22:33

Sounds stuffed in that case. the LED is in series with the optocoupler in them normally, so if its not lighting then something else is going on.

Jaycar are pretty good about replacing IME, they had better be with their markups tho.

Richard rich.ms

timmmay

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#401507 7-Nov-2010 22:46

Thanks Rich, I appreciate the help, i'll take it back next weekend.

elldizzle

91 posts

Master Geek

#401751 8-Nov-2010 17:01

I had mine wired wrong first and it did exactly that. Just stayed on regardless of input. I then mucked around with polarities and got it working. The way mine is wired the input from the USB is opposite polarity. i.e the positive goes to the negative of the input and the negative goes to the positive.. This is how I had to get mine to work..I'm using the exact same relay as you....Works fine Now. Just want to wire in a pot now so can adjust the speed...

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timmmay

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#401772 8-Nov-2010 17:24

Guess i'd better try again then! Do you remember what you had wrong? Does the red light go on when the output circuit is working or when the input circuit has 5V applied?

elldizzle

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Master Geek

#401776 8-Nov-2010 17:28

The light goes on when the input voltage is applied. And stays on till input voltage is taken off. Im pretty sure It's the input polarity that I changed in order for it to work....But will check the circuit tonight when I get in and let you know exactly how its wired...It did take a bit of head scratching and swapping around of wires to get it working.....It's just wired up on a breadboard at the moment...

timmmay

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#401777 8-Nov-2010 17:30

I tried both polarities already... my power supply has multiple tips that can be plugged in either way around, when I switched it nothing happened.

Oh well, back to Jaycar, but i'll do another test just to double check.

elldizzle

91 posts

Master Geek

#401783 8-Nov-2010 17:42

Yeah looks like a dud mate....

timmmay

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#401793 8-Nov-2010 18:12

Ok well I tested it again, and when I plug it in with the polarity OPPOSITE what it says to use it works fine. Light comes on, output circuit is completely, everything works fine. I guess I just wasn't using it right and I had a brain fart while I was testing it. Now when quickly wired up turning on the TV starts up the fans, turning it off turns the fans off :)

Thanks for pointing out how to use it properly :)

elldizzle

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Master Geek

#401868 8-Nov-2010 21:29

Ha ha yeah it's so random that the polarity's are opposite of the label....Glad you got it all working mate!....

timmmay

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#401871 8-Nov-2010 21:35

I just have to solder the connections in place and close the box up and i'm done. Might go do that now :) Glad you pointed it out, i'd have looked like an idiot in Jaycar if they tested it and showed me it was working... stupid labels though!

I'll probably post a bit of a build and photos thread some time too.

elldizzle

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Master Geek

#401873 8-Nov-2010 21:37

That would be great would love to see how it turned out...

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