Recycling Parts From Dead Motherboards

An anonymous reader writes "I had this dead motherboard on my hands and I wanted to see what would happen if I cut out the clock generator and used it stand-alone. So I removed the Winbond chip from the motherboard (I cut out the section of PCB with a hacksaw), powered it up and it was still working. Add a display, a microcontroller and two switches, and I got a cheap frequency generator. Here's my progress so far. Be kind to my Web skills, I'm really just a hardware monkey. It's not completed yet, but I just wanted to get the idea out there."

Comments

Re:I could use one of these

[Michael's a Jerk!]

What frequency range?

The price is something like $20, including transformer, PIC16F628 Microcontroller, FTDI serial to USB chip, etc. The problem is the clock chip. Places like radio shack etc aren't likely to have them.

The hardest part is learning PIC assembly. PIC's are weird devices, having an accumalator style, havard archecture. Take a look here for a good tutorial on PICs.

Re:ool, but a Waste of Time

[Michael's a Jerk!]

OK, OK. I'll let you in on a little secret.

If you want cool plans for how to build electronics stuff, google for 'DIY pic projects' for starters. Or you could just click here

There is a *huge* hobbiest crowd porgramming PICs to do all sorts of cool things. The chip takes maybe a day to learn the basics, and 2 or 3 weeks to master. The chip is around $4, and the programmer under 20. check out the Piclist for free tutorials, projects and code.

If you think it's cool, then go for it.

Hey, I resemble this article!

[sec]

However, I find that it's easier to remove components from circuit boards by taking a heat gun (ie. the kind you use for removing paint) and using it to melt the solder. Yes, on high heat, most heat guns get hot enough to melt solder. Just direct the gun at the back of the circuit board while gently prying or tapping at the component you're trying to remove from the front.

Just be sure to do this in a _very_ well ventilated area (ie. outside) because if you leave the heat gun in one place too long, which you probably will sooner or later, you'll burn the board, which produces some of the most evil smelling smoke you've ever had the misfortune of smelling.

Also, I find that dead motherboards aren't particularly fertile grounds for component salvaging. Once, I got a whole skid full of old scientific instruments at a government surplus auction for $10. The load of components I salvaged from this was quite unreal!

there's a better answer

[alizard]

I think the general solution for your problem and the problem of many people here who have an occasional need for test equipment like signal generators, frequency counters, etc. is to find a connection for used / surplus electronic test gear.

You generally don't need the latest / greatest / hottest for what you're doing, there's probably vacuum tube gear that is alive, well, and will probably solve some of your problems if you poke around a bit for a lot less money than you'd expect, especially if you value your time.

Most metropolitan areas have at least one or two places for this sort of thing.

Google is your friend. Try searching on:
used electronic test
or on the specific gear you want.

Not to say there's anything wrong with this project, it's a cool hack and anyone who gets into electronic hardware is going to have a growing pile of junk to recycle parts off.

limited utility

[frovingslosh]

The clock chip in question (and others like it) produces some pretty specific clock frequencies, but overall the frequencies provided don't seem to have much use. On the other hand, he's added a pic to the process, and by itself the pic could output a wide range of frequencies under program control. True, it can't directly output as high of frequencies, but I don't know what big use he could have for that limited selection of high frequencies.

I do like the idea of a usb controled and powered frequency source, but I would settle for lower frequencies but greater tunability than just a dozen presets and use the PIC directly. Or better yet, use the PIC and a multiplier circuit if you want the high frequency values the PC clock circuit offers.

Since the clock chip in question uses a 14.318 mhz crystal and PLL frequency multiplication to get the higher frequencies, you might even be able to still use a hacked MB clock circuit, but feed it a clock generated by the PIC rather than from the clock crystal. The top end would still be lower with this approach (better to just use a stand alone PLL and a divider feedback circuit), but it would allow one to get reasonably high frequency by very tunable signals.

Halogen lamps work, too.

[XNormal]

Blacken the solder you want to remove with a candle. Wipe the soot from parts you don't want to heat too much. If necessary, cover them with aluminum foil. Place the circuit close to a high powered halogen lamp and - presto. Even PGA parts with high pin count can be pulled out with relative ease (try doing that with a soldering iron and wick!)