DFN1006 TP-RCLAMP3321P ESD Diode Low Capacitance

Filter 18.432M

TC2199M failure phenomenon:

To start with, I decided to take a precise approach. I removed the bootstrap and replaced the booster capacitor, but upon powering on, the boot process was unexpected and the gun wasn’t accurate.
Then I tried re-adding the field supply filter capacitor, parallel with the boost diode, and also the output capacitor. Still no luck.
Next, I prepared another round of tests by replacing the field block and the boost diode. Unfortunately, that didn’t work either.
I measured the field block LA7840, and found pins 4 and 5 at 2.5V, 3 and 6 at 24V, and pin 2 (output) at 12V — all normal.
It looked like this problem was hiding deep. So I decided to go for a heavy approach — removing all peripheral components of the field block and testing the core part directly.
After half an hour of checking, I still couldn’t find anything wrong. Could it be the LA76810A? I referred to the schematic for TC2199F:
TC2199F .pdf
Measuring pin 23 of LA76810A gave me around 2.65V, which seemed okay. But when I looked closely at the image, I noticed it was slightly larger. Was the field excitation signal a bit too high?
I used an MF47 meter set to DC 0.25V range to measure the voltage from pin 23 to ground. The meter has an internal resistance of 5KΩ at 20KΩ/V.
I didn’t even look at the reading because I was watching the clock. Then, suddenly, the normal picture appeared on the TV screen.
After turning off the power, I measured the resistance from pin 23 to ground and found it to be over 18KΩ. That’s when the truth finally came out.