Hard-wire Power for Laptop?

I have a Compaq Presario R3000 series laptop. It's two years old, and has the dreaded power plug issue. I've had it replaced twice.. but its no good again.

I'd like to look into hard-wiring the power jack right to the mother board.. i.e. cutting off the male plug, removing the female jack, and soldering the wire right to the board. I know its dangerous because of being pulled on, etc.. but this laptop sits on a desk 24/7 and doesn't travel, etc (mostly because of this issue).

Any thoughts? Do'able? Any reads? Should I just pay to have it done?

 

Well, I would recommend replacing the connector with something more industrial. Something that provides a better "positive" connection and is secured to direct strain/stress to the chassis, and not the mainboard.

I would not recommend directly soldering the cord.

 

So I don't have to replace the female jack on the mobo with the factory default one? I can pick a different one (match size) that may last longer?

 

Hmm. Something like this?

http://notes.dpdx.net/2006/03/18/fixing-ac-power-plugs-in-various-hp-and-compaq-laptops/
http://www.delanoscientific.com/cpq1675.html

 

For the best possible connection, you may want to go hardcore and use a BNC connector. It wouldn't get confused for being anything else, and it will hold on so tight the rest of the computer could get torn to pieces before it would let go.

 

is BNC rated for the current draw?

 

yep.

With the connector secured to the chassis like that, the stress of the cable moving isn't gonna pull on the PCB and it won't tear out, again.

 

No idea, but I've never managed to overload one. I ran 110VAC through one once; I had it set up as a detachable connector crosslinking the power switch with the keyboard lock, so I could keep the computer from being turned on when I didn't want it to be used. Used that setup for a couple of years before I got a better computer.

 

VERY interesting thought. I use BNC's for CCTV use daily.. they are 75ohm typically.

So check this out.

http://www.amphenolrf.com/products/bnc.asp?N=0&sid=46085E801CBE17F&

500 volts peak, 1500 volts RMS for both 50ohm and 75ohm connectors.

This is an interesting suggestion. BNC is as secure as it gets for a simple connector.

 

I could have sworn that BNC stood for British Naval Connector, but that url says "Bayonet Neill Concelman". Anyone know what's correct?

voltage doesn't matter as much as the current, which is not listed by that paper.

 

Not sure, to be honest (regarding BNC name). As far as current, good question. I can call some of my vendors tomorrow (amphenol being one of them...). I just am not looking forward to taking this thing apart and soldering connectors. Never done it before..

 

i thought it was british naval as well, i even told someone the other day that it stood for that, alas imadumbass http://en.wikipedia.org/wiki/BNC_connector

 

Google finds me connectors 1A through 10A.. but obviously I need to find a female board mount solder connector.. Still searching.

 

Compaq service manual states power cable must have min current capacity of 10A, nominal voltage rating of 125 or 250 V AC..

"The Wide range input feature of the notebook premits it to operate from any line voltage from 100 to 120 or 220 to 240 V AC"

Stand-alone power requirements are:
Nominal operating voltage: 14.4 V DC
Maximum operating power: 60 W
Peak operating power: 65 W

External Power Supply:
Operating Voltage: 90-264 VAC RMS
Operating Current: 1.6 A RMS
Operating Freq Range: 47 - 63 Hz AC
Maximum Transient: 4/50 kV

 

Any other info we need? I'll send this to some BNC manufacturers tomorrow and see what they come up with. Obviously I need a male and female.. Anything else?

 

you should use a panel mount connector with solder tabs, solder a reasonable gauge of wire from it to the motherboard. Even if you find a board mount BNC socket it wont match the foot print of the existing conector, nor would it be very strong when inserting / removing the connector.

BNCs are designed for signals not power distribution which is why that link does not specify a current rating. I dont think they will cause a problem as long as you can solder directly to the conductors with a reasonable guage of cable.

 

Stranded conductor? Like a 20awg? 18awg?

 

stranded, yes... large enough to support the current draw.

 

Ay

 

I think it would be better to use a connector that you can attach to the outer case of the laptop (perhaps with a compression nut that threads onto the connector body) and solder wires from it to the motherboard, so you won't damage the motherboard if you yank the cord, as would happen with a connector that solders directly to the board.

 

Yeah, thats what I'm planning on doing..

 

Okay. I'd heard mention of board-mounted connectors, and I wanted to make sure you had considered the potential for damage given that BNCs don't release on their own.