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Now let's learn how to disassemble

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Straight-air hot gun

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Temperature to 450 degrees

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Adjust the air volume to the maximum

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Best to use this 4mm medium nozzle

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First, we put the tweezers under the chip

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Keep the tweezers as low as possible

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Do not angle the tweezers too much

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If it's too much

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When picking the chip later, it is easy to push the chip in the opposite direction

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It is easy to distort the surrounding components

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So we try to keep the rear a little lower

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When twisting the tweezers, it picks up from bottom to top

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You can also use the method we just mentioned to pry

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It's up to you

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I generally like to pick in this direction

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In the process of disassembly, the straight-air gun is best to point to the chip vertically

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The lower edge of the nozzle is about 1-2 mm away from the chip

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Don't be too high, otherwise it will easily melt the surrounding components

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Another thing is that we're working under the microscope now

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The microscope is right above

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So when we disassemble, we have to tilt the nozzle a little bit

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Because I need to work under the microscope to show you

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For normal maintenance, I may put it directly on the desktop to blow

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After the tweezers are placed, blow

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Do not poke with tweezers while blowing

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Sometimes the tin has melted and it is easy to touch the side

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When the tweezers are ready, move the nozzle over

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Lower it as possible as you can

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Pick it while blowing

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Pick this chip off as soon as the tin melts

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How can I know if the disassembly temperature is suitable?

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Just look at the solder joints on the motherboard

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We have now observed that more than 80% of all the solder joints under the disassembled chip are in this very flat state

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Just when the tin was a little soft, we picked up the chip

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If it is disassembled, most of the pins under the chip are in the sharp state that my tweezers are pointing at

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It means that the nozzle has been blowing this area for too long when it was dismantled

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And the temperature was high

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If so, it is easy to distort the surrounding components

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The second is that the small components with glue or chips that are relatively close to the periphery of the motherboard are prone to be tin extruded

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Missing soldering or internal tin extrusion,short bridge and short circuit

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The back of the motherboard, like the motherboard of our mobile phone

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Basically, components are mounted on both sides

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The chip we are soldering now has a hard drive on the back

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The hard disk is also this kind of chip with glue

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In the case of blowing for a long time, the hard disk on the back is easy to short-circuit

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Therefore, the temperature we disassemble must be well controlled

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Then we disassemble a chip in another way

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Pick from the bottom

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Temperature remains the same

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Done

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The heating time of this chip is a little longer than the one we just removed

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Now this chip has more than half of the solder joints in a melted state

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The individual solder joints still haven't melted

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But there is no probem with this

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It's all about the sign of melting of the solder joints

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If all melted

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There might be a problem on the back

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Or the surrounding places

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The is the disassembly method