New case

[Brian Ferrell]

I was thinking about asking the manufacturer of my new PC to cross-ship a replacement full tower case in place of the one I have now which doesn't have enough bays for an internal CD-RW. I will probably do the work myself. I've worked with electronics and done internal repairs before, and although I don't do it for a living, I've fixed things that pros haven't been able to, so I know something. I've never repaired a PC before, though, and since this was a major investment, I don't want to screw it up. Is there anything special I should know about changing cases? Do I
need demagnetized tools and what about static electricity? Do I have to worry about these things even though I probably won't be replacing any chips? Will the internal connections probably be a lot different?

Brian F.

 

[Emeric]

It's really no big deal. A few things to keep in mind:

- Static is an issue, but as long as you touch an unpainted metal part of the case before pulling out cards, you'll be ok. Don't shuffle your feet on the carpet between touching the case and removing the component though.. Handle cards buy there edges and try not to make contact with any of the IC's.

Some cases have a removable tray - so you can install the mainboard outside of the case, and then just slide it back. Can be easier, but not a critical feature.

- remove all cables, cards, hard drives, floppies etc. If you don't have some spare static bags to put them in in the meantime, place them on a piece of cardboard (low static).

Remove the motherboard

- Use a smaller screwdriver, most computer stuff is phillips(demagnetized, doesn't matter - I like one that has a slight magnetic pull to it, some of the mainboard screws can be tricky). When removing the screws on the motherboard, or anywhere else, try not to drop the screwdriver (i've done this a few times, with no bad result fortunatly), and be carefull not to scratch it. Usually 6 screws. Angle it slighly up when removing so that you don't scratch the bottom of the motherboard on of the riser posts below each screw.

- when putting the motherboard in the new case, no need to use 50ft/lbs of torque on the screws that secure it, just tight. In otherwords, don't over tighten. I've found with some cases it's difficult to handle the motherboard by the edges and still get the thing in, - if it's a slot 1 processor (or even ppga) you can hold on the top of the cpu when lowering the board into the case.

- keep ribbons and other cables away from the CPU fan - for ventilation reasons, as well as you don't want a ribbon to stop the fan. You may want to pick up some small nylon tie straps to neaton it up.

- Watch that the red strip on each ribbon cable is on pin 1 of the motherboard and pin 1 of the device it's being plugged into. On hard drives pin 1 is nearest the 5/12V power connector. On floppies, it's the opposite (99% of the time).

Outside of that, you should be fine. Just take your time.




[Edited by Emeric on 08-09-2000 at 09:21]

 

[Slackmaster2K]

Well, you're basically building a machine from scratch. The only difference is that once it's all together, *technically* all you should have to do is turn the power on and you're good to go.

Some things:

- Static. Make sure you have a nice large non-conductive and non-inductive surface to work on...like a wooden tabletop. Set all the components on this tabletop, not on the carpet. When you're starting from scratch, there's no good way to *ensure* that you won't zap anything, but you can minimize your chances by simply touching the metal case often, even if the object you're looking for is no where near the case. You know that nasty zap you get when walking across carpet and touching a doorknob? That's what we're trying to get rid of. Once the motherboard is in, I usually rest a forearm on the case while working inside. This will ensure there is no difference in potential between you and anything in the case. No, you shouldn't plug it in. If you leave the P/S plugged in, you're only increasing your chance of zapping something (or having something blow up).

These days most computer components are very robust. I toss cards and memory and whatnot around without much thought.

- Size matters. You must make sure that you get a case with the same form factor as your motherboard. This will be either AT (baby AT) or ATX.

- Screw it. The motherboard is attached to the case by screws and standoffs. There are two types of standoffs, plastic snap in, and metal screw in. The metal standoffs are drilled out so that they can be screwed. Oh yummy. So it goes, case->standoff->motherboard->screw. You can pretty much use a screw whereever there's a hole in your motherboard. While you don't have to use a lot of screws, I'd recommend at least 5. Think logically, wherever you're going to be pushing on the motherboard, it needs to be well supported!

Plastic standoffs are real simple. Most snap into the case on one end and either snap into or rest under the motherboard on the other end. Use these to fill any remaining holes in your motherboard. The reason we have these plastic standoffs is that it's much easier to remove the motherboard if you don't have to worry about 20 screws.

Before sticking the motherboard in the case, a word of caution. Make sure you snap the little plastic feet onto the bottom of the case, or you might have to remove the motherboard to get them on. I've run into this a couple times...duh.

- Connections. Watch how you take the machine apart, and reverse the process to put it back together. The only difference will be the connectors to the case....lights, and switches. There will be a diagram in your motherboard manual, and the connectors from the case will be labeled. All you have to figure out is which line is + and which is -. This is easy when one line is black, but when one is orange and the other is yellow, it's kind of a guessing game. The good news is that if you screw up, your lights simply won't work right so who cares. Turn the machine off, reverse the connector, and whammo, the light should work (etc).

Again, watch how you take the machine apart to understand how to get it back together. Take notes. Draw pinout diagrams (e.g. which direction should you plug that cable in?)

A few tips:

- Pin one on most ribbon cables (IDE, Floppy, etc) will be marked...usually in red.
- The pinouts on the motherboard will be labeled usually. Or at a minimum, pin 1 will be marked. It should be somewhat obvious, if you look around an entire connector and notice a mark in one corner only, that's pin one. If you have a nice motherboard, all the pins will be labeled with numbers.
- Pin one on an IDE device is almost always towards the power connector. Pin one on a floppy is almost always AWAY from the power connector. If you reverse a hard drive or floppy cable, you probably won't do any damage, but you'll notice its light will come on and stay on, and it won't work. Turn the machine off, reverse the cable, and try again.
- You MUST remove all cards though AND the CPU and memory. Trust me. Start with a bare motherboard.
- Remember the order in which your cards were installed. This will determine the IRQ they are assigned by the motherboard's BIOS. Usually Windows can adapt itself if you move a card around (it maps its own IRQ's), but it really depends on how it's setup. Don't make things hard on yourself.
- Remember where your drives were plugged in. This will ensure that they all get the proper drive letters when you restart.
- Remember to punch out all necessary holes in the back of the case before putting the motherboard in. Once I had a computer 99% done, only to realize that I forgot to punch out the USB hole. Because of the way the case was built, I had to remove the entire motherboard to punch it out!
- Make sure you have long enough IDE cables for any situation. If the ones in your machine now are little shorties, get some longer ones. Your CDROM drive is going to be way up there if you get a big case!
- Remember to plug the fans back in for cryin out loud!

Wow, I wasted a lot of time. I gotta run. This is all a "just do it" type of thing. So just do it. It's hard to get the motherboard in....sometimes really hard with a cheap case. Just be patient. Don't force anything but don't be afraid to use a little force (just don't use force with a screw driver or you'll put a whole right through the board!).

Slackmaster 2000

 

[Brian Ferrell]

Wow!!!!! Thanks for the detailed info, guys. Now all I need is the guts to "just do it" or the patience to send it back to the factory and let them "just do it". ;-) I didn't think I'd have to remove the cards, memory and CPU, though. I know you're right, but it's pretty scary.
Hey, I can finally see what all those smilies are; with my Netlink and TV they were too blurry.
Thanks again for taking the time for such detailed replies.

Brian F.