No power on or after the machine crashes or the heat machine has a noise fault, which is caused by the virtual soldering of the main chip U1 (MSD6A838UVC), which causes the chip to be soldered.
The reason is mostly that the black heat sink on the top of the U1 main chip has a fixed-foot soldering off at one end, which causes the gap between the heat sink and the main chip to become large, causing heat dissipation, so
Will cause the main chip to be soldered or the main chip temperature is too high and damaged. When you encounter this problem, first remove the heat sink, then use the BGA rework station to the main chip U1.
For repair welding, the BGA rework station repair temperature can be set at 255 degrees Celsius or 260 degrees Celsius. After the repair welding is completed, the test machine can be loaded back. If the sound image is normal,
Put the heat sink back (requires the heat sink must be installed in place), and at the same time apply some thermal grease to help dissipate heat, then solder the heat sink and print it.
After the hole is worn, use a soldering iron with a slightly higher temperature to heat the repair. Do not allow the solder to flow from the back to the front, and then prevent the back of the printed board from passing through the hole.
The tidal blue paint layer, use a small knife to gently scrape out the diameter range of about 1MM and then replenish the solder, as shown in the figure below, which will have a strong fixing effect.
Remarks: After this method is processed, it will not be de-soldered due to the heat sink, causing the chip to be soldered or damaged.