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Moving laptop motherboard into desktop chassis

Discussion in 'Building a new PC' started by mynamevincenttt, Jan 13, 2014.

  1. mynamevincenttt

    mynamevincenttt Newbie

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    Hey guys,

    So I know through extensive research that this is for some reason looked down upon, and I understand all the drawbacks. That being said, I have an old overheating inspiron 1720 that I have tried completely cleaning and replacing the thermal paste. I have decided that the next best step would be to add a heat sink onto the motherboard and call it a day. This however requires a new case to accommodate the new heat sink. I have an old desktop that I was just going to throw out, so I figured I should just use it in this project of mine. I got a new laptop, so this inspiron has since been just collecting dust in my closet. What I would like to accomplish is to move it into a case, put it under my tv, attach a wireless keyboard and mouse, and use it as an HTPC. I realize this is a bad idea, but after doing so, I would like to be able to leave it on for days at a time.

    So heres my idea:
    I would drill into the case and mount the laptops motherboard onto the case. After doing so, I would simply feed the power chord into the desktop and plug it into its usual place on the motherboard. The laptop also has a VGA port that I would use to plug it into my plasma TV. This however leaves me with 3 problems that I hope you can help me out with. First of all, I would need to find a way to power this thing on, seeing as how the laptops power button is on the motherboard. Second, I would then have to figure out a way to extend the usb ports and such to the exterior of the case. Lastly, I would need a way to turn on the power supply so I can run the fans on the case.

    Ive searched everywhere and there have been no well documented cases of people completing this project, the main problem being those above. Hopefully with your help we can be the first! Ill add pictures as I go along.

    Thanks!
     
  2. ddp

    ddp Moderator Staff Member

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    how good is your soldering\desoldering skills?
     
  3. mynamevincenttt

    mynamevincenttt Newbie

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    Hmm.. not a noob, but okay at best. Why do you ask?
     
  4. ddp

    ddp Moderator Staff Member

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    desolder the laptop power switch & solder the leads of the desktop power button in it's place. have 2 choices for the onboard usb ports, 1: buy usb extender cables & mount the female ends to the case & the male ends into the usb ports of the motherboard, 2: desolder the usb ports off the motherboard, mount them to the case & solder new leads from the backs of the ports to the motherboard. what is the current power supply rated watts ouput?
     
  5. mynamevincenttt

    mynamevincenttt Newbie

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    I haven't taken anything apart yet, but it is an older, basic desktop (ran win xp) so it's probably something low wattage. For just running the fans ot shouldn't matter much right?

    Also, I think I made a mistake about the power button. I believe it's on the keyboard which is directly connected to the motherboard. (I can't post links, so if you Google inside my laptop inspiron 1720 and scroll down to where they take out the keyboard, you'll see) I think I'll have to leave the keyboard attached on top of the motherboard, which will cause a bit of problems for my plan. One being that it'll get in the way of airflow and the heat sink I wanted to put in. Any ideas? I'm open to buying a new case that is more easily opened so I can turn it on and a psu if needed.
     
  6. ddp

    ddp Moderator Staff Member

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    how about an actual desktop case instead of a tower case so that the keyboard can be mounted on the case's top tho will have to extend the keyboard cable to reach the motherboard?
     
  7. mynamevincenttt

    mynamevincenttt Newbie

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    I kinda do like the idea of laying it flat instead of upright.. I'll look into it. Also, I'm not sure what the connection is between the keyboard and the motherboard is, so I'm not sure if it's even extendable. Don't different laptop makers use their own standard for these types of things? As far as I know, dell might not even make a cable for this connection type, so it may not be possible to find a longer cable. I'm not sure, but I don't even know where I would start looking for it. What is it called?
     
    Last edited: Jan 14, 2014
  8. ddp

    ddp Moderator Staff Member

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    a true desktop case lays horizontal compared to a tower that is vertical. don't see desktop cases much except with maybe namebrand computer like dell. desktops have 1 case cover compared to 2 side panels for towers. the connection can be extended by desoldering the motherboard connector & adding extension wires from it back to the motherboard. i can do that as that was my job when working at celestica which was at 1 time part of ibm til the mid to late 90's. i worked on sever boards for sun microsystems, cisco systems & juniper systems besides working on nokia cell phones back in 1998 to 2002.
     
  9. mynamevincenttt

    mynamevincenttt Newbie

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    I see, thanks for the info. I'll open it up and keep you posted next weekend when I have time to start and get all the materials ready. In the mean time, how should I go about attaching a heat sink? The heat sink is attached to both the cpu and I believe the gpu and then attached to the fan, somewhere along the way there being a thermal pad on top of the northbridge(I think). Only the cpu has holes around it that I can attach a heat sink onto, so I dont think it is possible to replace it. This might be a dumb question, but would it help me at all to use thermal adhesive and attach a larger heat sink on top of the stock heat sink to help disperse the heat?
     
    Last edited: Jan 14, 2014
  10. mynamevincenttt

    mynamevincenttt Newbie

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    Just an update, I'll add pics later. I managed to attach the motherboard onto a cooler master Elite 361 case with 2 screws and a lot of zip ties. Dinky, I know, but it's holding up. Luckily, the holes on my motherboard fit normal sized screws and I was able to put the screws that came with the case through the motherboard. As for the rest of the holes, I've put in screws and a brass spacer on the other side to hold the motherboard above the case. Right now I have the case fans attached to the psu and was thinking of getting rid of the psu and using a molex to usb adapter to power the fans. You think it'll work? From what I gathered, the fans take like 1-2 V max and the usb ports put out 5V. Since there is a male and female portion on the molex connectors, I was thinking of connecting 2 fans to 1 usb port. Then I would have to find a way to configure windows vista and the bios on my inspiron 1720 to shut off power to those usb ports when the computer is sleeping but keep power on the port I plan to use for a keyboard/touchpad adapter.
     
  11. ddp

    ddp Moderator Staff Member

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    that fans are 12 volts not 1-2 volts. also the usb port kicks out 5 volts at 500 millieamps.
     
  12. mynamevincenttt

    mynamevincenttt Newbie

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    Yeah I just realized that right now. It should be fine right? I just finished swithing the red and yellow wires on my molex connectors so it would put out 5v instead of 12v to make it quieter. Airflow in the case is very good so reducing fan speed should be fine. Would usb ports put out enough amps to power these fans?
     
  13. ddp

    ddp Moderator Staff Member

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    what is the numbers in front of the "a" on the fans?
     
  14. mynamevincenttt

    mynamevincenttt Newbie

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    .16A, should be good?
     
  15. ddp

    ddp Moderator Staff Member

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    nope as 5v x .16a = .8a or 800ma.
     
  16. mynamevincenttt

    mynamevincenttt Newbie

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    Hmm.. as much as I liked college physics.. I have no idea how that works. So I'll trust you on that and say.. dang. I guess I could get a remote controlled outlet and turn that on whenever I use it..
     
  17. ddp

    ddp Moderator Staff Member

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    i did it wrong so .16a is 160milliamps which is below 500 millieamps of the usb port.
     
  18. mynamevincenttt

    mynamevincenttt Newbie

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    Cool, thanks. But apparently usb to 4 pin adapters don't exist outside of ebay.. Also, know anywhere I can get a 2x usb male to internal 9 pin male connector?
     
  19. mynamevincenttt

    mynamevincenttt Newbie

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    I just wanted to make sure of my math before I start splicing wires and blowing up my usb ports. V = IR would be idea here right? If my fan is rated at 12V DC and .16A, then the resistance would be 75 ohms. Putting that back in at 5V would get me to 66mA which would be fine for the amount of current a usb port can put out. I've been doing a bit of searching and people are saying that the fan would draw more current if I were to run it at 5V and blow my ports. Also, I've already swapped the wires on my psu molex connector to the 5V (red) wire instead of the 12V (yellow) wire and the fans run fine. Assuming it really is 5V being put out by the psu, it'd run the same as if I were to plug it into USB right? Just making sure so I dont explode something and start a fire.

    Thanks!
     
  20. omendata

    omendata Regular member

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    Yip saves me some typing thats the way i would go.
    To start the pc you could use WOL but that would require an rj45 cable to your router, its the option i use for all my servers , pcs and laptops in my flat (all 11 of them) lol

    Maximum power output Usb Port = v x i = 5 x 500/1000 = 2.5watt

    If the 500mA current rating of a USB port is greatly exceeded, a polyfuse may 'blow' and become open circuit.
     
    Last edited: Feb 1, 2014

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