Answer these questions below.
Are you sure that you place the chip in the correct position?
Did you check the resistance of the chip with a multimeter?
Did you set the heat gun or hot air to the correct temperature?
Because if you fail one of this the result will be the same. The chip might be dead due to high temp too much hot air will damage the chip.
Anyway, Look at this video to get some idea on how they check the resistance of every ASIC chip and find the correct chip based on the logs and the correct temp for air flow.
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https://www.youtube.com/watch?v=5WH7g61d90w