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geekhack Projects => Making Stuff Together! => Topic started by: katushkin on Sat, 04 November 2017, 09:59:04

Title: Electronics/wiring questions
Post by: katushkin on Sat, 04 November 2017, 09:59:04
Morning/afternoon/evening all,

I'm looking to see if it's possible to wire up a small circuit board with a mains connection to an internal, typical computer PSU. The board I have is this (http://www.ebay.co.uk/itm/VST29-03X-HDMI-AV-VGA-TV-USB-Multimedia-LCD-Controller-Board-TV-PC-DVD-DIY-Kit/121085303937?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649) which I have a power adaptor for already, but I would ideally like to run this screen and the PC it is plugged into off one plug.

It says it needs a 12V 4A power input to the board which plugs via a standard round shaped power connector (not sure what the technical term is) and I was hoping I could convert a 6 or 8 pin connector from a modular PSU into a connector like that but I have absolutely no experience in wiring at all!

Any help you could provide would be awesome.
Title: Re: Electronics/wiring questions
Post by: TalkingTree on Sat, 04 November 2017, 11:39:51
Yes, you can do that with any PSU and with either a 6 or 8 pin connector as 12V is on both connectors.

(http://cdn.overclock.net/2/2b/500x1000px-LL-2bf838c0_st45sf-g-modular-pinout.png)

As for actual wiring, what I would do is to cut the female end of a 4 pin extension Molex cable (https://www.scan.co.uk/images/products/1837-a.jpg) and solder the yellow and black wire (check polarity) to the coaxial power connector (http://www.mpja.com/images/19084-large.jpg) for your board. Know that there are many different coaxial plugs so bring your power supply to your electronics store and ask for an identical plug to solder.

Current wise, 4Ah is pretty low current for a PSU, any unit with at least 150W will do.
Title: Re: Electronics/wiring questions
Post by: katushkin on Sat, 04 November 2017, 13:40:46
Duuuuuude that's perfect. So if I take a 6 pin, and just do what, pin 1 and 2? Then take a molex connector like pictured, cut the connector off, then use the yellow wire to pin 1 and the black to pin 2, then the other ends to the connector?

I'm not sure where I would go in the UK as we don't have that many electronics stores... Might have to go online and look.

Good news about the amps, my knowledge of electronics past basic PC construction is pretty limited :))
Title: Re: Electronics/wiring questions
Post by: TalkingTree on Sat, 04 November 2017, 13:59:01
Correct. Pin 1 and 2 are 12V and GND.
(https://i.stack.imgur.com/IA43b.jpg)

They must be soldered to the short and the long prong on the Coaxial plug respectively. Just like in this picture, but the red wire will be yellow in your case.
(https://playground.arduino.cc/uploads/Learning/9V_tut_3.jpg)

PSUs have the female molex so that's the one you'll be chopping off.
(https://upload.wikimedia.org/wikipedia/commons/thumb/3/31/Molex_female_connector.jpg/220px-Molex_female_connector.jpg)

Double check what's your power plug (https://en.wikipedia.org/wiki/Coaxial_power_connector#Standards) as they are very similar to each other.
Title: Re: Electronics/wiring questions
Post by: katushkin on Sun, 05 November 2017, 11:13:19
Quote from: TalkingTree on Sat, 04 November 2017, 13:59:01
Correct. Pin 1 and 2 are 12V and GND.
Show Image
(https://i.stack.imgur.com/IA43b.jpg)


They must be soldered to the short and the long prong on the Coaxial plug respectively. Just like in this picture, but the red wire will be yellow in your case.
Show Image
(https://playground.arduino.cc/uploads/Learning/9V_tut_3.jpg)


PSUs have the female molex so that's the one you'll be chopping off.
Show Image
(https://upload.wikimedia.org/wikipedia/commons/thumb/3/31/Molex_female_connector.jpg/220px-Molex_female_connector.jpg)


Double check what's your power plug (https://en.wikipedia.org/wiki/Coaxial_power_connector#Standards) as they are very similar to each other.

You're the man

(https://media.tenor.com/images/b24bb9ff41a82800534691ccb10776d6/tenor.gif)
Title: Re: Electronics/wiring questions
Post by: TalkingTree on Sun, 05 November 2017, 11:31:21
(https://media.tenor.com/images/a3c06d4e50bf02b2ba66240dc4938703/tenor.gif)