Building computer from old parts. Worth the effort?

There are quite a few GQ-type questions in this post, but i’m also asking for opinions, so i thought IMHO was the appropriate forum.

My wife and i have two very new computers between us, a desktop (mainly mine) and a laptop (mainly hers). The laptop was the most recent purchase, impelled by the death of a desktop she had been using. The desktop stopped working, so we took it into the shop and the guy told us that the motherboard was fucked, and that the power source had exploded, killing both optical drives (1 CD, 1 DVD). He thought, however, that the hard-drive, RAM, and processor were probably OK.

So today i pulled the old computer apart (my first time inside the guts of a machine) because i’ve always wanted to know how they go together so that i can build my own next time. I now have all the components separated, and my inventory is as follows (if the guy at the store is to be believed about what works and what doesn’t):

Dead Stuff
[ul]
[li]Matsonic motherboard (not really sure of the exact model, as there are so many numbers on the thing)[/li][li]L&C LC-250ATX power source[/li][li]FC HIS-305 AGP[/li][li]Raite CD-RW Drive[/li][li]Samsung DVD Drive[/li][/ul] Working Stuff
[ul]
[li]Seagate ST320432A HDD, 20Gb[/li][li]Intell Pentium III 733MHz 256/133/1.65V processor with heat sink and fan[/li][li]2 x 128Mb PC133 SDRAM[/li][li]ADMtek AN983B ethernet card[/li][li]One white case[/li][li]Floppy Disc drive[/li][/ul] My first instinct was to try and put together a system using the salvaged parts from the old computer and buying cheap stuff on eBay (or somewhere) to fill in the gaps. I’m wondering if this is going to be worth doing?

A quick check on eBay suggests that a power supply can be had for about $10, and that what appears (to my inexperienced eye) to be a compatible motherboard can be had for $25. Then i’d just need a video card, which would only have to be a very basic one for this computer., and could also be had pretty cheap.

If this is all true, and if the stuff i have now actually works, it seems that i should be able to get a basic system up and running for about $50, plus my time. Given that i’m interested in learning how to do this stuff anyway, this seems like a reasonable deal. Or is it all a waste of time?

Now to my GQ-type questions:

  1. The computer guy told me that the processor and the RAM from the old computer seem to be OK. How likely is this, really, given that the blow-out of the power supply apparently fried the circuits in the graphics card and the optical drives? What about the ethernet card?

  2. When i removed the processor from the motherboard, the processor came away from the heatsink/fan assemby. Now there’s old, sticky heat-paste gunk on the top of the processor and the bottom of the heat sink. Can i safely scrape the stuff off each of these surfaces, buy some new thermal paste, and put them back together again?

  3. When reading about motherboards and case confirgurations, i keep reading about AT and ATX. What’s the difference, and how do i tell if the motherboard i see on the internet is going to fit in my case.

  4. How much power do i need in a power source for a computer like this. The specs on the back of the old one seem to say that it’s 125W. Can this be right? Nowdays, they all seem to be 350-plus.

  5. The old 20Gb hard drive still has all its old information on it. Will this present a problem when using it in the new computer? Also, is there anything i need to know about getting a motherboard that’s compatible with the HDD?

Any answers or advice would be most appreciated.

  1. The computer guy told me that the processor and the RAM from the old computer seem to be OK. How likely is this, really, given that the blow-out of the power supply apparently fried the circuits in the graphics card and the optical drives? What about the ethernet card?

Its possible. You could put it in your new desktop and see if it works. You don’t have to take out the one thats in there now.

  1. When i removed the processor from the motherboard, the processor came away from the heatsink/fan assemby. Now there’s old, sticky heat-paste gunk on the top of the processor and the bottom of the heat sink. Can i safely scrape the stuff off each of these surfaces, buy some new thermal paste, and put them back together again?

Yes.

  1. When reading about motherboards and case confirgurations, i keep reading about AT and ATX. What’s the difference, and how do i tell if the motherboard i see on the internet is going to fit in my case.

AT is an obsolete standard. There are two 6 wire connectors that attach to the MB.
ATX is the current (or almost current) standard. It has one connector with 2 rows of 10 wires. Almost all Pentium III MBs use ATX.

  1. How much power do i need in a power source for a computer like this. The specs on the back of the old one seem to say that it’s 125W. Can this be right? Nowdays, they all seem to be 350-plus.

If you are going to get a replacement P3 motherboard, 250W should be enough.

  1. The old 20Gb hard drive still has all its old information on it. Will this present a problem when using it in the new computer? Also, is there anything i need to know about getting a motherboard that’s compatible with the HDD?

There shouldn’t be any problem with the HDD itself. That copy of Windows on it is set up specifically for the old dead MB though. You should boot up Windows in safe mode and remove any drivers and other installed sw specific to the old MB before you let it boot normally and find drivers for the new MB. Sometimes you can’t get rid of all of the old drivers. Then you have to wipe the disk and reinstall. This seems to be especially true with VIA chipset motherboards.

Unless you have a name brand computer with a screwy case, that only fits that motherboard, the only motherboard compatibility you have to worry about is the processor.

Even cheaper than EBay is going to amateur radio shows (Hamfests). You missed the one in Timonium by about 2 weeks or so, but there is another at Montgomery County Fairgrounds coming up soon. (www.arrl.org) Be aware that some of the dealers at Hamfests sell crap. Caveat Emptor.
Any answers or advice would be most appreciated.

I’m far from an expert user, but I have been building my own systems for quite some time now. I don’t know alot of specifics, but I guess alot and it usually turns out for the better :). I build a new computer about every 18 months. When I do, I scavenge parts that I want to keep and use them in my new computer. All the left over parts gets rigged together into a piecemeal computer and I usually donate it or give it to a family member. So yes, I would say that it is worth the effort.
When you took apart your computer, did you have an ESD wriststrap on or were grounded somehow? Hopefully you didn’t take it apart on the carpet in the livingroom. All is not lost even if you did. I once found 128 megs of ram in Compusa’s dumpster and to my surprise, it worked fine. If you do plan on building, get a rubber mat and an ESD strap.

http://motherboards.bizrate.com/buy/products__att7--2426-,cat_id--419.html
Here’s a list to some compatible motherboards.

All newer pentium style computers are generally ATX. AT was the first generation. Although, I do believe that some micro desktops use AT, but thats besides the point in your case.
I’m not sure about the viability of your network card, graphic card, and optical drives. One way to find out is to hook them up to your own computer to see if they still work. I would just assume they are working and if it doesn’t boot when you are done, you can start replacing items. I’m not sure about the thermal paste either. I used a razor blade and cut as much off with the processor as I can and don’t bother gluing it again when I put it on a new motherboard.
I wouldn’t doubt that the power supply is 125 watts. Older chips didn’t need as much power as they do now. The more components you have the more power you need obviously. With all these power sucking video cards you need 350+. You can get a 300 watt power supply for as low as 30 bucks.
Your old HDD is compatible with virtually every motherboard out there. There are exceptions, but you’re fine. Unless you know how to configure a computer, I think that’s where you will run into some problems. Do you know how to dink around with the BIOS?

Thaks for the advice, folks.

I did contemplate such a strategy, but i really don’t want to go messing around in the guts of my brand new computer, especially when i have so little experience. I’d prefer to take a risk with the RAM itself, and buy new stuff if it turns out to be no good.

Actually, given that i don’t need any of the data off the old HDD (it was all backed up and is now on our new computers), i would probably just format it and reinstall everything. That way, i’d have a nice clean drive with a fresh installation.

I just did it on the floor, i’m afraid. I had read about shorting out ciruitry with static electricity, but for some unknown reason it never occurred to me that this would happen when taking an old computer apart. Oh well, too loate to worry aobut it now; i’ll just be more careful in future, and will take your advice about the grounding equipment. Although some of the websites i’ve been reading suggest that simply touching a grounded computer case before working with the equipment should help avoid any problems.

I’ve never done it before, but i’ve been reading a few guides on building your own computer, and lots of them have advice and tutorials for changing BIOS settings.

If the power supply blew up, 125W wouldn’t surprize me at all. Remember, if the power supply was big enough for the system, it wouldn’t have blown up.

-lv

That is a good precaution but everything should still be OK especially if you were working on a hard floor and it is summer so that minimizes the risk.

How did the guy know that the two optical drives are blown? It is very possible but certainly not a given. It seems more likely to me that the connection to the motherboard was no good after it blew. Did he test them in some other way?

No idea. I guess i just took him at his word.

The fact that we got charged for 90 minutes of labor in order for him to tell us that the computer was fucked suggests to me that he must at least have run a few tests. These guys are the local geek shop, i’ve used them before, and they have a reputation for being very fair with labor costs.

Anyway, given what you’ve said, i won’t throw the optical drives out. I’ll keep them and test them on the new system once i get it set up.

I’m sure you’re right, although it did blow up after almost four years of constant use, which doesn’t seem beyond the realms of for an adequate power supply.

I would not skimp on a cheap power supply. It would be my guess that the former power supply was the cause of your blown motherboard and components. Consider buying a nice new case for this “learning” project. You will be able to use it again when building your monster system in the future. :slight_smile:

What are your plans for it?

While I head about people using their old boxes for hardware firewalls and/or routers on their home network(s), the only thing I ever did was turn one into a digital jukebox hooked up to my stereo.

One of the main purposes of doing this would simply be for me to get some practice building my own box without spending any real money, so that next time i need a new computer, a few years down the track, i’ll be able to do it myself.

Actually, i figure that if it works out, using it as a jukebox might be a really good idea. Either that, or my wife could use it at home and keep her laptop for mobile computing (research trips, library visits, college work, etc.).

Can you explain how you do this in safe-mode a bit more? I assisted the suicide of my old computer (with ME) a couple of days ago when I accidentally killed its power souce while plugging it in to take things off of the drive; a plastic crate covered with a fleece blanket is a great source of static, I learned. I can’t believe I’ve had computers of my own for seven years and never realised you could harm one that way :smack: The plan is for my dad to pull its hard drive, assuming it’s undamaged, and put it into my new computer(XP), and I do want the information off of it. I really really want the documents, music and pictures that I didn’t get to back up.

Until I toasted that computer, it was really stable, so I have very little experience using Safe-Mode for anything. How do you find the drivers to uninstall them? Control panel add/remove programs? And when you say “find drivers for the new MB” do you mean I should look for the drivers ahead of time, or it will on its own once the old drivers are off?

If the old drive is going into a complete new computer and won’t be the boot device (primary master), you don’t have to do all this. You can access your files fine if you install it as primary slave, or secondary slave or sec. master.

Reboot and press F8 until a menu comes up. One of the choices will be safe mode. You are right about going to Control panel add/remove programs for some of the drivers. Then go to Control panel/System/Hardware/Device Manager and delete all the rest for hardware that won’t be in your resurrected system. You really need to get rid of the ones for the motherboard itself. The chipset drivers for the onboard IDE controllers have to be removed. Using the wrong IDE drivers will cause Windows to boot in compatiblity mode, and your CD drivers won’t load.

The OP’ster said he wanted to reuse the old CPU; a Pentium 3. Since those are obsolete, I’m assuming that he wants a used MB. He’d have to download the drivers from the internet if the replacement motherboard doesn’t include a driver disk and manuals.

Sorry if I’m rambling. I tend to do that.
bwb

Don’t scrape. The Pentium III is a “flip chip” design - previous processors had the actual silicon protected behind a metal plate, acting as a heat spreader. On the PIII, the metal plate was dispensed with, so that bluish square in the center is the silicon. It won’t take too fondly to being scraped. At best, wipe it gently with a soft cloth to remove the old thermal paste.

Thanks for the warning.

Given the dangers of mucking around with the silicon, would it work to simply leave the excess paste there and apply more when i reseat the processor? Most of the gunk has collected not on top of the chip itself, but around the edges of it. Thoe top of the chip has a bit of stuff, but most of it is exposed metal.