Manutenção de placas de vídeo

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Manuteno de placas de vdeo

Por Carlos E. Morimoto em 1 de agosto de 2007 s 08h04

Assim como no caso das placas-me, a maior parte dos defeitos em placas de vdeo esto relacionadosa capacitores ou outros componentes do circuito regulador de tenso. Voc pode notar que as placas devdeo que do mais defeitos so justamente os modelos com consumo mais alto (e placas usadas porlongos perodos em overclock), onde estes componentes so mais exigidos, e no placas baratas, que

operam a baixas freqncias e utilizam dissipadores passivos.

O sintoma mais comum que a placa torne-se menos estvel com o tempo, devido deteriorao doscapacitores, travando com cada vez mais freqncia at que o dono resolva substitu-la ou a placasimplesmente pare de funcionar definitivamente, fazendo com que o micro deixe de inicializar o vdeodurante o boot.

A instabilidade causada sobretudo pela perda de eficincia dos capacitores, sobretudo em placas queainda utilizam capacitores eletrolticos. possvel substituir capacitores em placas de vdeo, assimcomo no caso de placas-me e em muitos casos o conserto realmente vale pena, pois muitas placas devdeo atuais custam muito mais caro que uma simples placa-me.

O Tech Arp publicou um tutorial bsico de manuteno de placas de vdeo, dividido em duas partes. Sevoc se interessou pelo assunto, vale pena dar uma olhada:

Parte 1: http://www.techarp.com/showarticle.aspx?artno=399

Parte 2: http://www.techarp.com/showarticle.aspx?artno=402

Date : 01 July 2007Manufacturer : N/ASource : N/ACategory : GuidesAuthor : Empire23Revision : 2.0Forum Link : Discuss here !Views : 192883

Graphics Card Repair Guide Rev. 2.0

Graphics Card Repair

This is going to be a simple guide on repairing most physical damages that may afflict your graphicscard or other add-in boards. Do note that this kind of work will void your card's warranty. So, if yourcard is still covered by warranty, you do not want to resort to this method.

Tools You Will Need


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1. One 40-watt soldering iron with precise tip. I use a Hakko DASH 35W iron.

y 40 watts is a good figure to go with. The higher the wattage, the faster you can melt the solderBUT at the same time, a high wattage may cause heat-related damage. Therefore, 40W is agood figure to go with.

y Precise tips are nice because they allow for a higher heat density and more importantly, bettersoldering precision. Since SMD pads are pretty small, precise tips make it easier to soldercomponents onto them. Smaller tips also help you avoid hitting any other components as youwork.

2. A multimeter with a continuity beeper. I use a Fluke 179 multimeter.

y This allows you to check your work after you're done. If the multimeter beeps for a second orso and then stops, that means your work was successful.

y Multimeters also allow you to check your solder connections, the state of the pads, traces andother things.

3. A solder sucker. I use a Hakko DS-1 solder sucker.

y As its name says, it sucks solder. It allows you to fix bad patches in your work, e.g. when youput on a little too much solder.

y It also allows you to remove old solder and stuff like that. Very handy indeed.4. Some solder wick. I generally use either Kester or Hakko solder wicks.

y Solder wicks are reels of flux-impregnated copper braids. When you heat it up on top of solder,it absorbs the molten solder. Essentially, they work like solder suckers, but far greater controland precision.

5. Pliers and cutters.

y Somehow, you'll always need these handy tools, so keep them close. Any brand will do, as longas they can fit into tight spaces and are easy to handle.

6. Solder!

y Obviously, you will need some solder to well, solder stuff. For SMD work, I recommendeutectic solders because they cool fast and don't slur and cold joint as easily. Remember to getthinner solders, because they allow for more precise work and faster heating.

Important Precautions

1. Do not rush any soldering jobs. You can take your time when you solder SMD components. Theyare designed to withstand reflow soldering for up to ten seconds. The same doesn't apply for throughhole though. Just plot out your plan of action and take your time. Rushing yourself will often result inmore errors and time wasted on corrections.

2. Clean and tin your iron tip before you start on a joint. It makes everything much easier. You can trymy technique which I callscraping. All you need is an old heatsink. Just use its fins to scrape residue


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off the iron while it's still hot.

3. You need lots and lots of bright lights where you work. Light is one of the most under-rated issueswith any workspace. You need bright and white lights. Flexible study lamps are perfect for this role.

You can't solder what you can't see, can you?

4. Get some eye protection, my friends! Eutectic solder and large diameter solders have a tendency tosplash. Ouch!

The Sacrificial Victims

Now before we start on the guide, let's take a look at the sacrificial victims. We have two damagedNVIDIA graphics cards on our hands. One is missing a 1 microhenry SMD choke with a bentcapacitor. The other has one capacitor's legs torn off the pad with another capacitor that got torn off its

pad.

Sorry for the poorly-focused pictures. The loss of my camera's eyepiece and my astigmatism were no

help at all. But you should be able to see the capacitor that fell off, and its pad on the card.

The card with the missing choke actually works, but I don't think it's stable. No good at all, but that'swhy we are going to repair it.

A Closer Look At The Damage

At a glance, this section of the card did not look like there was anything out of place. But if you look closelyat the capacitor circled in red, you can see that it is actually torn off the pad and is not in proper contact.


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Here, the card is missing an inductor and a 16V, 330uF capacitor is precariously seated and actuallywobbling loose. Might as well fix that at the same time.

The Workbench Setup

Now let's take a look at my simple setup. First up is my trusty soldering iron - the 35W Hakko DASH,sitting in a heatsink which I used for "scrapings".

Next is my multimeter which I use to test the circuit. Remember the various modes you'll have to use. Notethat because it is an active circuit, you cannot actively test the component you fixed, because the othercomponents will affect it. What you should look for are pulses of life.

To do that, measure across the capacitor's legs.

1. If the continuity test gives you a constant beep the second you put it on, you probably have a shortcircuit.

2. If the continuity test gives you a single beep and then stops, then it should be working, because thecapacitor is charged up.

3. If the capacitance test gives you a figure and then goes to zero, you should have done the solder workthe right way. Just remember to discharge the capacitor first by measuring the voltage or using a highvalue resistor.

If the capacitance shows OL, even after you've discharged and connected the terminals properly, you'veprobably done something wrong or created a solder bridge.

Repairing The DamageBroken Capacitor Leg

First of all, I would like to apologize for not providing more photos in this guide. The nature of the workrequires me to use both hands and constantly move the card around. The DSLR I use just doesn't work wellin such situations. Maybe I will post up a video in the future, so stay tuned.

Let's start with the capacitor that has one leg broken from the pad.

1.


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2. Clean the pad of its original solder. Yourcurrent solder may not mix well with the oldsolder. You can use the solder wick or soldersucker to do this. All you need to do is tiltthe cap slightly upwards, put the wick on the

pad and heat the pad. Alternatively, heat thepad and suck up the solder.

3. Now, add a nice blob of solder of your own.Not too much though, just enough to coverthe capacitor's legs when you push it into thesolder blob.

4. The leg of the capacitor you want to push into the pad should be bent downwards, from its 90 Lposition. If you imagine the top of the capacitor as 12 o'clock and the leg at 9 o'clock, bent it down tothe 7 o'clock position.

5. Now heat the pad again, and use the pliers to push the capacitor downwards so that its leg goes intothe blob of molten solder. Use some force to bend the capacitor's leg as it touches the pad, so that itstaightens out into its original 9 o'clock position.

6. Let the joint cool.

If You Make Any Mistakes...

We're just human, and I'm quite sure most of us have a tendency to put too much solder on the pad. After all,it's better to have more than less, isn't it? Well, it does mean that you will have to clean the extra up.

Because the solder sucker sucks everything in one go, we need something that will give us more control andprecision. So, we will use a solder wick to clean up the excess solder.

1. Cut a small section of solder wick.2. Put the solder wick onto the area with excess solder.3. Put the soldering iron onto the area with the solder wick in front of it.4. Do this for 5 seconds, and then pull the wick and iron back at the same time. If the amount of solder

absorbed isn't satisfactory, repeat this step. Do remember that the speed of solder collection varieswith time and the amount of pressure you use when you push the iron.

5. You should generally get a pretty decent joint like in the picture below.


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Of course, you can do better with a hot air rework station, but those cost around $1600 each. I don't think the

average Joe can afford one. Neither can I!

Repairing The Damage

Broken Capacitor

Now, let's attend to the capacitor that was totally removed from the pad. Fortunately, it was not missing, just"decapitated".

1.2. Clean the pad of its original solder. Your

current solder may not mix well with the oldsolder. You can use the solder wick or soldersucker to do this. All you need to do is tiltthe cap slightly upwards, put the wick on the

pad and heat the pad. Alternatively, heat thepad and suck up the solder.

3. Now add your own solder to the pads. Thequantity needed is a matter of experience ortrial and error if there's a lack thereof. Isuggest putting just enough solder to coverthe top of the joint and no more.

4. Start work on one side. Bend the leg of the capacitor on that side to the 7 o'clock position.5. Heat up the pad and hold the capacitor with your pliers.6. Push the bent leg onto the solder on the pad and apply pressure until it straightens out and points to

the 9 o'clock position.

7. Hold the pliers steady as you pull the iron out and let the joint cool.8. Repeat steps 3 to 6 for the other leg.

These two pictures illustrate a pretty decent solder joint. You can use the solder wick to clean up the excess

solder for a superior joint, as well as a much better looking one!


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Badly Seated Capacitor

This capacitor is badly seated. If we don't fix it, it could eventually come loose and break contact with thepad. Best to fix it while we are at it. Besides, this is much easier to fix than the two previous problems.

Generally all you need to do is :

1. Heat one pad.2. Apply a constant downward force on the capacitor and pull the soldering iron back.3. Let the pad cool.4. Repeat for the other side.

Yeah, baby! Perfect joint!

Repairing The Damage

Missing Inductor


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You might be wondering about the missing inductor. Well, Ihave no idea where NVIDIA got their inductors from but Iwould choose Pulse's or Murata's SMD inductors as

probable replacement.

Unfortunately, it's really expensive to get Mouser.com toship them all the way here... until I build up enoughquantity. But rest assured, if I do make a purchase and the

card is still here, I will post an update.

However, fixing the inductor is no different from replacinga capacitor. Heck, it should be easier due to its lower profile.

1. Clean the pad of its original solder. Your current solder may not mix well with the old solder. Youcan use the solder wick or solder sucker to do this. All you need to do is tilt the cap slightly upwards,

put the wick on the pad and heat the pad. Alternatively, heat the pad and suck up the solder.

2. Now add your own solder to the pads. The quantity needed is a matter of experience or trial and errorif there's a lack thereof. I suggest putting just enough solder to cover the top of the joint and no more.

3. Start work on one side. Bend the leg of the inductor on that side to the 7 o'clock position.4. Heat up the pad and hold the inductor with your pliers.5. Push the bent leg onto the solder on the pad and apply pressure until it straightens out and points to

the 9 o'clock position.

6. Hold the pliers steady as you pull the iron out and let the joint cool.7. Repeat steps 3 to 6 for the other leg.

Hands On Approach

Don't try this unless you know what you're doing!

For those who love getting their hands (fingers actually)dirty, you can substitute pliers with your fingers. Using yourfingers actually give you superior control and speed.

Of course, if the capacitors heats up too much due, they willprobably burn your fingers. Even worse, you rish contact

with your soldering iron. Lose your concentration for asecond and you may very well burn a hole in your hand!

I personally prefer using my fingers, because I've burned them too many times to really matter anymore.

The Litmus Test


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After all those soldering, it's time for the test. Will it work? Or will it blow my system to smithereens?

OMG! Great success! It lives! The card is ALIVE!

Well, that wasn't so difficult, was it? All you need is somesoldering tools and a little chutzpah. So, the next time youdrop your card and knock out a few surface-mountedcomponents, and doNOThave any warranty to count on,you can now fix the card yourself.

If you are feeling a little more adventurous and want totackle smaller components that are harder to repair, we havea more advanced graphics card repair guide.

Anyway, thanks for reading, and I hope you have tons offun doing these repairs, and of course, great success too!

Graphics Card Repair Guide Part 2 Rev. 2.0

Advanced Graphics Card Repair

Now that you have already learned how to repair broken capacitors and inductors on your graphics cards(or any other boards), it's time to move on to the smaller components that are harder to tackle. These includesurface-mounted resistors and capacitors. So, this second guide on graphics card repair will show you howto repair small, chipped-off SMD components.

Do note that my handiwork isn't that good in this guide because I just couldn't find my missing 0.2 mmsolder tip. However, as unsightly as it may seem, the joint work shown in this guide will suffice not only asa demonstration but for actual repair work. So, let's start with what you need to get started and move on

from there.

Tools You Will Need

1. Everything listed in the first graphics card repair guide. If you have not read that yet, please start withthat guide first. It's a good primer before you start on this guide.

y One 40-watt soldering iron with precise tip. I use a Hakko DASH 35W iron.y A multimeter with a continuity beeper. I use a Fluke 179 multimeter.y A solder sucker. I use a Hakko DS-1 solder sucker.y Some solder wick. I generally use either Kester or Hakko solder wicks.y Pliers and cutters.y Solder!


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2. Isopropyl alcohol

y Alcohol is a great solvent, and a very good flux cleaner. Generally, you can use it in conjunctionwith cotton buds to clean up your work and make it look presentable.

3. Cotton Buds

y Used to clean up excess flux in tandem with isopropyl alcohol. Get tightly wound buds so the fibersdon't get left behind. If in doubt, just get a box or bag of the expensive ones.

4. Tweezers

y My choice would either be Cooper Handtools or Erem tweezers. Both are extremely well-built, easyto handle and made specifically for electronics.

Important Precautions For SMD Work

1. Same basic rules as that of the first graphics card repair guide. Again, if you have not read it yet,please do so before continuing with the guide, especially if you are new to soldering.

2. This time, using your fingers is a ticket to Burnsville. Don't try it. That's what the tweezers are for.3. If you can't see, don't dip your head closer. Get a magnifying glass or mentally estimate the

component's position and the time needed for the soldering work. Putting your head very close to ahot soldering iron with hot tin and lead = a disaster waiting to happen!

4. Get some eye protection, my friends! Swimming googles work in a pinch. Eutectic solder and largediameter solders have a tendency to splash. Ouch!


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Ti i M

M it i t Take yourti e wit your work and you will do a betterjob.2. When you hold SM component with a tweezer, it bestto hold them at an angle of30 from the

horizontal. Incidentally, thatis also the best angle to use if you ever need to look for hidden landmines with a knife. Awesome.

3. Since the pads are smaller, try using a flathead (slotted tip) screwdriverto scrape and chip off excesshardened solder on the pad. Do so very gently as you don't wantto knock off any surroundingcomponents!

Our Patient Today

Before you getto work, always take some time to understand the problem at hand. A short 10-minutesession to plan the work never hurts. In fact, it will help you avoid costly mistakes (in time and money) inthe long run. Now, let's take a look attoday's patient.

Waaaait. Doesn'titlook familiar? Yes, itis the same graphics card that we repaired in thefi ii i . LOL! In my hurry to remove it from my computer chassis, I slammed it againstthe case

and out popped a surface-mounted capacitor.... So sad. You can see the recovered capacitor and its pad inthe second picture.

Oh well, this misfortune does give us the opportunity to fix her up again. And I had better do it, or we willget an earful from NVIDIA!

Preparing The Solder Pad

Method A - Using A Lead-Free Soldering Station

1. First, set your soldering station to a temperature that suits the melting temperature ofthe solder on the

board. In this case, a temperature of around400 C

or so should be fine.


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2. Use the soldering iron to melt the solder on the pad.

3. Together with the soldering iron, use the solder sucker or a solder wick to remove the molten solder.

Method B - Using A Screwdriver

1. Using a flathead (slotted tip) screwdriver, lightly chip off the excess solder on the solder pad.

2. Scrape away the excess solder until you reach the pad itself and have a level surface to work on later.

Remounting The SMD Capacitor

1. Melt some solder onto ONE of the pads. Just a little bit is more than enough. Remember, the pads of

SMD components are small, and close to each other. You do NOT want to solder two adjoining padstogether!

2. Grasp the capacitor with the tweezer. As mentioned earlier, an angle of 30 C from the horizontal is agood angle to use.

3. Heat the pad with the soldering iron until the solder melts again.

4. While grasping the capacitor, apply a downward force as you slide the capacitor onto the pad with themolten solder. Let the joint cool and solidify.


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5. Then melt and apply some solder to the other pad and let that joint cool.

6. Finally, test the circuit to make sure it works.

Cleaning Up

1. Clean up any excess solder with the solder wick. The method is the same as what we covered here.

y Cut a small section of solder wick.y Put the solder wick onto the area with excess solder.y Put the soldering iron onto the area with the solder wick in front of it.y Do this for 5 seconds, and then pull the wick and iron back at the same time. If the amount of solder

absorbed isn't satisfactory, repeat this step. Do remember that the speed of solder collection varieswith time and the amount of pressure you use when you push the iron.

2. Dip a cotton bud into some isopropyl alcohol.

3. Use the cotton bud to swab the area around the SMD component until all the flux has been cleaned up.

Conclusion


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There you have it - a totally well-soldered surface-mountedcapacitor! Now, it may not look at nice as it should, but the

joint should work well enough. If you have a fine-tippedsoldering iron, you can certainly do a better soldering jobthan that.

As you can see, repairing even fine SMD components likethis capacitor isn't that difficult. All you need is somesoldering tools and a little chutzpah. So, the next time youdrop your card and knock out a few surface-mountedcomponents, and doNOThave any warranty to count on,you don't have to sit and cry. You can now fix the card!

If you want to ensure a professional-looking joint, take your time when you do these repair jobs. A goodpositional magnifying glass helps a lot, especially when you are working with small SMD components. Forthe extra touch, use isopropyl alcohol to clean up the flux after you are done.

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