Written by Zago
Published on 2020-07-21 09:12:12
Last edited on 2020-07-24 11:05:21
Replacing a thermal pad and dusting off an Asus motherboard.
I have old hardware! What now?
You finally got hold of some old hardware, but it needs some TLC before using it. Here are my tips on how to get started.

Congratulations! You have just entered the rabbit hole that is vintage computing. You start with one PC, then you want to get another one, then you want to experiment with something else, then you run out of space, then you don't care and start hoarding everything that smells old... I can't be the only one, right?
Of course, like every product ever made, your hardware wasn't meant to last forever or, at least, it has weak spots which will inevitably end up killing it. But don't worry, you can get some actions done to prevent the early departure of your vintage electronic toys.
While writing these down, my first thought was about computer motherboards and printed-circuit boards. Some of what follows might not make sense for other parts. It's not a perfect list, but I hope it will be useful for someone out there.

1. Clean it. Just clean it.

It might sound obvious, but a good cleaning always helps. If the previous owner didn't bother to clean the stuff before handing it to you, it's time to get a soft brush and gently wipe off the dust between the components on your board. Use an anti-static or natural brush, so you don't fry sensitive chips with unwanted electrostatic charges. If you need something quicker and a bit more aggressive, you can use compressed air, but try to avoid that in a particularly dry environment, as the friction of fast moving air on still objects can create static.
You might find out that you need a much deeper cleaning method, especially if the hardware was used in a smoker's place or in an industrial environment. In this case, you need the big guns: get a stiffer brush and some isopropyl alcohol and start scraping away the gunk. You could also do a pre-wash by removing any battery still on the board and giving it a coarse scrub in a bath of soap and water. Don't use the board for a while afterwards, as water will still be under some components, even if the rest is completely dry: you can speed up the drying by blowing on it with a fan, don't use a heat gun or a hair dryer as heat might damage plastic or even warp the board itself.

2. Get rid of the corrosion

You can find two levels of corrosion: environmental and chemical.
The first kind is easy to fix and you absolutely heard of it before: oxidation. It happens by water and air reacting with metals and it's almost unavoidable. Symptoms of this are intermittent operation of peripherals, sudden lockups and, with audio devices, pops and crackles coming through microphones or speakers.
Sometimes, unplugging and reconnecting plugs and boards from connectors and slots helps cleaning just enough to make stuff work again. If the oxidation layer is too thick to come out on its own, you can use contact cleaner on both male and female sides of the connector and remove and insert it a bunch of times. Easy enough.
Next, is the nastiest and worst type of corrosion you can find. If a battery or a capacitor dumped its corrosive contents on the PCB, you will find a green haze on the metal around the culprit, ugly signs on the board and darker than usual traces. Sometimes, it can happen if something spilled on the board while in storage and started doing its fatal effect.
Since the chemicals inside a battery or a capacitor are usually alkaline (low pH), you can neutralize them using an acid (high pH). You don't need extremely aggressive acids; white vinegar is perfect for the job: dump a little bit of vinegar where the damage occurred and leave it alone 30 minutes or so while it reacts with the alkaline. Then, rinse and scrub the area with isopropyl alcohol and a toothbrush. If the damage was superficial, you should be almost good to go; if the chemicals made their way to eat the traces and the pins of the components, you will need to repair them, if you can. Bear in mind that if the board is too far gone, you are better off salvaging the good parts and sending it to e-waste (unless you are some kind of electrical engineer and you are OK with rebuilding half a PCB from scratch).

3. Replace bad parts

I'm fairly sure you've already heard of the "capacitor plague": a bad chemical mixture caused caps to stop working properly and to bulge and eventually leak overtime. This is especially true for hardware manufactured in the early 2000s and, to a lesser extent, late 90s. Also, 70s and 80s tantalum capacitors tend to short out after a while and, if there is no short circuit protection anywhere, they tend to explode quite violently as current starts to flow through. Even if the caps look good and you don't see any corrosion on the board, I wouldn't take the risk of starting to use stuff that will fail in an unknown amount of time (could be minutes, could be weeks, could be years...), new capacitors are relatively cheap and overall better built.
The next most common failure is with old batteries: after they run out juice, they let their corrosive juice out. This is almost sure with nickel-cadmium batteries and early lithium cells. If you see one still on the board, remove it with no remorse. It's way safer to use different approaches, like CR2032 coin cells or other kinds of replaceable battery packs: be aware that some batteries were rechargeable and the boards had charging circuits, so you might need to add a diode to avoid getting current from the board to the battery.
Replacing parts is usually not too difficult: you need soldering equipment (a decent soldering iron, a solder sucker, solder, and flux are usually the minimum required to start) and the new components. The electrical diagram of the board is a nice addition, but it is not very easy technical documentation to find for newer hardware. I'm not going to write a soldering guide, so refer to your favorite YouTube channel where you can watch a "professionally produced" video about the topic. In case you aren't geek enough and you don't have a preferred YouTube channel about soldering and desoldering, I suggest to check out Adrian's Digital Basement: he covered multiple times this topic and this kind of repairs with nice in-depth videos.
I'm starting to prepare some recapping manuals for the boards I currently have, so you can refer to a simple document for location, polarity and values of capacitors for some boards. I hope it will be helpful to some people out there, since I got boards which got some of the caps removed by a previous owner and I wasn't entirely sure of what components I needed to repair them.

4. Go with the (re)flow

Electronics work if they are connected to each other (duh). In some cases, you might find instabilities even if you do not have connectors and slots to oxidize: it's because solder joints are starting to fail. It's relatively easy to notice: you power something on and it's not working at all, but, after a couple of power cycles, it magically works again; or it works for a while and it starts to behave erratically.
It can happen on old boards where heat cycles might have broken the solder or newish boards manufactured during the transition to lead-free solder. As the board warms up with usage, the metal expands and will either start to make proper contact again or completely interrupt the circuit.
If the components have through-hole pins, it's quite easy to retouch the points with the soldering iron and a touch of fresh solder; if the parts are surface mounted with exposed contacts, you might be able to do it with a steady hand and a finer tip; finally, if the parts are on ball grid arrays, you need a professional reflowing tool for a permanent fix, although you might be lucky and get it to work by heating up the board with a heat gun or a oven (but don't count on that, it is most likely a temporary solution).

5. Maintain and preserve

As for every electronic circuit, the key to longevity is proper maintenance. As soon as you start seeing a strange behavior, it might even be too late. Even a simple visual inspection can assess if maintenance is needed: if you see leakage from a capacitor, rust forming on steel parts, dust and grime collecting, you know something needs to be done. Storing your hardware in anti-static bags with a desiccant bag and in a dry place will help limiting the risk of electrostatic discharges destroying components and of moisture corroding metal surfaces.
Every now and then, you should use them, even for just an hour, to make sure everything is still working: capacitors are happier when current gets flowing through, so the dielectric content doesn't completely dry out; hard drive bearings need to turn, otherwise the lubricant oil or grease might dry out or gum up and prevent mechanical parts from moving as intended.
If something needs a thermal interface material between the heat source and the heatsink and it is not using a thermal pad, remember to change the thermal paste: I usually do it every 2 years, because I cheap out on my thermal compound and it dries out quite fast, but with a good quality one, an application can last even 10 years. Don't wait until it gets rock solid, as the exposed dies of some processors and graphics cards are extremely fragile.
To clean off thermal paste from a CPU, I suggest you use IPA and a soft brush to first agitate the compound, then wipe it off with a cotton or microfiber cloth: in my experience, paper towels tend to get too abrasive with thermal paste and they will scratch off the markings etched on top of heat spreaders.
Also, if you have to work with the fragile pins in a LGA socket and you don't have the factory cover anymore, I suggest to keep a CPU in the socket, so they don't get bent if it gets handled harshly. The same applies to thin pins on PGA processors.
RAM sticks can be stored close together, but remember not to shake the box or to "massage" them when they are touching each other. The small surface-mounted bypass capacitors near the RAM chips can be tore off the board like nothing and if enough of the caps are missing, you might find impossible to run the RAM module at the full rated speed.

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Zago wrote this article

Born in 2000, the Millenium Bug affected me by making me believe to be in 1998 and that Windows 98 is still cutting-edge technology. Modern and retro tech enthusiast, I'm studying Computer Engineering while maintaining, developing and writing for this website.
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