Replacing a DC connector by cables : safe or not ?

A

aquelito

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Hello,

I am quite interested in the motherboard below, a Ling Jiang PCM5-QM77 : socket G2, thin mini-itx with a PCIe x16 slot, wide input.

Only issue is the weird DC connector, which is absolutely not standard. Seems also a Chinese component from the company Palyoo.

To solve this issue, is it possible to desolder the DC connector and replace it by two 14AWG cables (one +12V, an other GND) ?
The idea is to directly power the board with an open-frame 12V PSU, such as a Meanwell EPP-300-12V.

Is there a risk to kill the motherboard ?

I5-CPU-Mini-ITX-industrial-Motherboard-6xCOM-1xDP-1xHDMI-Rich-Digital-IOs-PCM5-QM77.jpg
 
Hm. Well, soldering around is always a risk, depending on how good you are with soldering. Definitely you'd need to practice on modern ROHS boards and expect the worst, like ripping a trace out of the PCB.
How does the back of the connector look like? does it have any exposed leads going down from the casing into the PCB or is it all boxed up? How large are the solder points on the bottom?
 
Hmm, well, figuratively speaking, you could try sticking it in the back! :D

Looks like you could try taking some (stranded) wire, cover it with a bit of solder, insert the ends into the square holes and just heat whatever's sticking out with the soldering iron.
It'd be a hackjob of sorts, but I think it's slightly safer than yanking the thing altogether.


connector_9v_backside.png
 
Woudn't it be easier to order the plug that fits in that socket and splice the wiring into it?

That way you don't risk damaging the board (and blowing your warranty).
 
michalrz Thanks !

Just to be sure, you mean inserting wires where the arrow are, then heat the connector legs above the mobo to melt the solder ?

solder.jpg


Leaves very few clearance for the iron !

rtangwai : yes, now that I have the exact ref, this certainly what I'm going to do.
Except I'll have this connector protruding from the back of my case, if I choose to use an internal 12V PSU. Not very safe either :/
 
You can heat the slack wire that'll be left protruding from the back side. Not necessarily the leads themselves.

The wires should heat up quickly enough and far enough inside to melt the solder which you'd have had placed on the wire beforehand.

The ends of the wire which would go inside would have to be coated in solder first. The connector casing and the solder should prevent them from falling out again. For bonus points, we'll always have hot glue to add to the sturdiness. Again - it's not the most beautiful solution and, as others mentioned, there's a more elegant way - to either make or get a proper cable and modify that instead.

I think that all of the above is safer than removing the connector, but - I wish I could vouch for luck :)

Edited in: Yeah, I mean those holes you arrow-tagged. The coated wire should be thick enough to go in with a little bit of force to make sure much of it touches the leads of the connector. Heating, say, an inch from the end should cause the solder coating to melt and adhere to the leads.
You can try this before soldering - just stick them in, run the computer and monitor if the connector housing remains cool/warm to the touch. If it gets too hot, it means the connection is not good enough and I'd abort.

Edited in later: you should use Pb/Sn (4:6) solder because it flows easier at lower temperatures. Leadless solder can be a pita to handle.
 
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Thanks again for your help. I get the picture :)

Either way (solder or male connector), the issue I forsee is the motherboard DC connector current rating. It is rated for 12A.

With a 45W chip and a GTX 1050 Ti single slot, I'm looking at around 13A max.
Having to rely on the connector leads may be not the safest bet...

The solution would be to make a powered version of the riser I intend to use and have it powered by my 12V open-frame PSU.
Good luck with that !

RnMbNjMl.jpg
 
Why so many folks being afraid of removing that connector?

Heat it up and use some desoldering braid and remove the connector.

Find a different DC connector with wires and solder the wires through.

This isn't some advance soldering stuff... if anything it is pretty basic and easy for a beginner.

You'll never use that non-standard plug and soldering into its butt cracks is going to void the warranty anyway.
 
It would be easy to solder directly to the pads on the back of the board.

That way you are not damaging the connector in any way and the board
will look fine if the wires are removed later.


solder_pads.JPG
 
why do you want this board in the first place doesnt look to offer anything in the form of something great or different from any other itx board why not go with a regular cheap ecs brand itx board and be done with it
 
DTN107 : thanks for the input. I guess I'll see when I'll have the board. I haven't soldered anything in a long time. I don't want to f*** up a 140€ board :)
But yes, that would be the easiest way to power the board : just two wires and a 12V open-frame PSU.

F6688883-01.jpg


Spartacus : yes, that could also be a good way to do it, just to test if the ! What is the right way to solder a 14 AWG wire on small pads ?

Jbort1984 : I am looking for a thin mini-itx motherboard with a full PCIe x16 slot, to be paired with a single slot GTX 1050 Ti :

- Thin IO shield to achieve a max height of 50 mm.
- No 24-PIN connector to reduce the cable clutter.
- i7 socket PGA988B like the i7 3610QM or 3630QM are still very much in the game performance wise, and cost no more than 50€.

This board has all I need, except for the non-standard DC connector (which is available on rs-online, farnell, mouser...).

There is also this cheaper LGA 1150 option but memory chips are soldered...
 
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>>Spartacus : yes, that could also be a good way to do it, just to test if the ! What is the right way to solder a 14 AWG wire on small pads ?

Use a soldering iron with a good tip on it and use lead/tin solder if you can find it. The no lead stuff is horrible to work with.
Make sure you don't buy acid core solder for plumbing!

You will probably need to wick up the solder on the pins and use fresh pb solder on them.

Strip back about 1/4" of insulation from the wire ends and tin the ends with solder. Then use some fresh solder and reflow the pins on the board.
Then hold the wire end up tight against the side of the pin (not the top of it) sticking up from the board and put the iron on it until the solder flows.
Hold it steady until it cools.

You could also use some type of in-line connector on the wires so you can connect/disconnect the wires easily when you need to.
Automotive 12v connectors work well for that.

ETA: Make sure you get the polarity right.

ETA#2: You want Rosin core solder and make sure the wire ends are flat against the board.

.
 
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Spartacus : thanks for the detailed explanations and the solder ref.

- Thanks for the polarity reminder. I have the connector pinout in the motherboard doc :)
- Do you have a particular soldering iron reference you may share ?
- What do you mean by wires ends being flat against the board ? I understood I had to press the wire ends against the pin sides.
Would be great if you had a picture.
 
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No particular soldering iron in mind. An inexpensive 30w iron should be fine.
Don't use those big 180w soldering guns, that's too much heat and you'll damage the board.

I should have said the wires should run flat on the board not the wire ends.

The wire end should be up tight against the side of the pin, at a 90 degree angle to the pin.
Sort of like if you hold your hands out in front of you and make a cross with your fingers.

.
 
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