Spontaneous VCC-Main Short After NFC Repair

Here are a few observations, questions and suggestions:

• What exactly did you repair? Did you replace or reball the NFC IC?
• Previously water damaged board…always a red flag and adds one, if not more, variable to the mix.
• Caps don’t go bad just from heat, it was probably flaky to begin with and may be related to the previous water damage.
• Solder balls squeezing out is never a good sign either, you probably applied too much heat. Sometimes this is of no consequence but in this case, it probably is related to your issue.
• Taking a flash picture seems to have caused a cascading failure. High current draw through the strobe driver, possible near shorts due to solder ball squeezing, excessive heat and probably bridging of solder balls.
• I would remove the Backlight driver IC to see if the VCC_MAIN short goes away.
• You could try connecting a battery instead of a DCPS to get a heat signature but this could cause catastrophic damage as there will be no current limiting. Another trick is to connect the DCPS directly to the VCC_MAIN rail and bring up the voltage slowly. You may get a tiny heat signature on the bad component at 2V before the other IC’s kick into gear.