Hello everybody!
In this video, I’m going to show you how to replace bulging capacitors on a motherboard,
why it should be done, and when it’s worth doing it.
Capacitors are among the most vulnerable elements you can find in motherboards, power supply
units and graphics cards.
Inside, they contain some electrolyte fluid, which tends to evaporate at high temperatures,
and it makes the capacitor inoperable.
In motherboards and power supply units, such elements are subjected to temperature effects
regularly.
As a result, bad capacitors can make a computer freeze, restart, show blue screens of death,
fail to start from the first attempt, or even fail to start at all.
Often, people believe that problems with their computers are caused by various software errors,
viruses or certain parts breaking down.
Capacitors rarely die in new computer parts, the only exception being faulty items.
However, if you notice any issues with your computer, it is worth examining the capacitors
- what if they are the root of
the problem?
How to determine bad capacitors It’s easy to tell a good capacitor from
a bad one.
Usually, the top part of a bad capacitor is swollen, and sometimes there can be brown
stains.
Seldom, the bottom part can be swollen too, which is also easy to see during a visual
inspection.
Also, you can test their capacity with a multimeter, but most of the time, a close look at the
capacitors can help you understand if there are any bad ones.
What you need for the work This is the list of what you need to replace
the capacitors: A soldering iron with a thin and narrow tip,
no more than 40 to 60W - if you use a more powerful one, there is a risk of overheating
the motherboard.
Flux, solder and something to remove flux from the motherboard.
It could be spirit or refined gasoline.
And the most important part - capacitors of required capacitance and voltage.
Remember, that if you get polarity confused or use a lower-voltage capacitor, it may explode,
so be very attentive when selecting an item for replacement and make sure that you install
it properly.
Read the markings carefully.
They always specify the voltage (6,3-10V) and capacitance (1,000-1,500 microfarad).
You can select an item with the same voltage that the old capacitor had or with a higher
one.
At the same time, capacitance effects the time needed to charge and recharge a capacitor,
and in some cases, this can be of utmost importance for the specific circuit.
That is why capacitance should be exactly the same as your old element had.
How to resolder capacitors First of all, to replace a faulty item you
should remove it.
Now that you have located the bad capacitor, you need to find its legs on the back side
of the motherboard.
There could be some difficulty in doing that, but as long as you are determined to do it
on your own, I’m sure you’ll manage it.
Once you’ve found the legs of the capacitor, start heating one of them, slightly pulling
the capacitor away from that leg.
As the solder melts, the capacitor will lean to the side.
Then do the same to the other leg.
You can try heating two legs at the same time and slightly sway the capacitor from one side
to another, from one leg to the other until it gets separated from the motherboard.
If you heat and sway it properly, desoldering a capacitor is easy.
When doing it, do not hurry or apply too much pressure.
Motherboards are made of multiple layers of fiberglass, and if you press too hard, you
can damage contacts between the inner layers of the board.
Also, long-time heating can also harm the motherboard.
It can get the solder pad to come off or peel away.
That is why putting pressure on the soldering iron is a bad idea.
Just position it so that it touches the legs and press very slightly.
If the existing solder on the motherboard doesn’t melt, try adding a little bit of
low-temperature solder.
In the past, most motherboards used lead solder, but the recent trend is to use lead-free solders.
The melting temperature of led-free solder is 20 to 30 degrees Centigrade higher.
Therefore, you need to heat the soldering site longer or use a higher temperature - and
we’ve just mentioned the dangers that can be caused by overheating.
There’s a good fix for that: before soldering, use a hot soldering iron to apply some low-temperature
solder on the capacitor legs on the back side of the motherboard.
This way you mix two types of solder to get a lower melting temperature at the junction
point you are going to work on.
When desoldering a capacitor, solder tends to fill the holes made in the motherboard
for the capacitor legs.
So if you try to solder the new capacitor in the same way as you desoldered it, there’s
a risk of damaging the solder pad and the circuit connected to it.
That is why you should remove the solder from the holes and make them a little bigger.
To do it, put a needle, a straightened paper clip or a toothpick into the hole from one
side, and touch the hole with a soldering iron from the other side.
When the solder is melted, the toothpick will slide into the hole.
It should be done very carefully as you may accidentally damage the circuits between te
motherboard layers.
If you use a needle or paper clip, rotate it so that it doesn’t get soldered.
But the best option would be to use a solder sucker or a desoldering braid (also known
as a desoldering wick) if you have it.
In case you’re using second-hand capacitors as replacements, remember to clean their legs
from any solder they may be covered with.
Now the only thing left to do is to solder a health capacitor in place.
Put its legs into the holes.
Here’s an important thing to remember!
At this stage, the most important part is not to confuse polarity: it is specified both
on the motherboard and the capacitor, so be very attentive.
I have mentioned the dangers of getting polarity wrong a few minutes before.
Usually, you can see special markings on the motherboard to make you work easier (the colored
part means the “minus” or negative contact), but it is also useful to remember how the
old capacitor was positioned.
The capacitors also have special signs on them, usually a strip with the “minus”
(negative) symbol.
Insert the legs into the holes, put some flux on them and solder them to the motherboard.
When the soldering operations are complete, don’t forget to clean this area of the motherboard
with a special fluid - something like a FLUX-OFF spray, isopropyl alcohol, ethyl alcohol or
refined gasoline.
Doing so is highly recommended as there might be tiny droplets of solder all over the motherboard
area that may cause circuits to cross and short out the motherboard.
Even the flux can come into reaction with other components, so it is better to be on
the safe side, and do some cleaning.
You may find bad capacitors anywhere else, where they can be causing trouble.
Such elements are used in power supply units, graphic cards and so on.
If you noticed bulging capacitors in another device, they can be replaced by following
this guide.
That is all for now!
Hopefully, this video was useful.
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Thank you for watching.
Good luck.