I have a project where i require to capture the difference between a functional L293D and malfunction L293D. For the malfunction, i take out the chip and zap it with 14vdc. Then after i capture the image, it shows that the chip that got zapped is colder than the others. is this a valid thing?
the malfunction chip is on the right side of the board
Interesting but not accurate. The part is rated at 36 volts. If you want a better answer post a schematic, not a frizzy drawing showing your circuit and explain the zap process. Also include all connections in your schematic. That is a nice picture of a circuit board but what is it?
You need to look at how ICs are constructed.
They have fine gold wires and/or strips connecting the pins to the semiconductor substrate, you would have fused those most possibly, making then open circuit, so no current flow, no energy dissipated, when inserted back into circuit.
No, because it might run hotter, or the same temperature, by chance - the datasheet won't say anything about the behaviour of a damaged device, unsurprizingly
There are various failure modes some might jam the device hard on, some hard off, others might happen to get stuck in an intermediate state, there's little to be gained worrying either way unless you are characterizing failure modes for reliability engineering I'd have thought.
How big is your budget, the semiconductor manufacturers spend a lot of money just to test and guarantee the final produce. What parameters do you want to check, how do you define a malfunctioning chip? What test fixtures do you have? Do you have environmental chambers to do both temperature and shock testing? What are your guard bands?