Dell Latitude 5420 (LA-K491P), won't turn on... diagnosis and repair continued.

In this case, we had previously diagnosed a DELL LATITUDE 5420 LA-K491P, which wouldn't power on and only charged via USB-C. We found that the EM5209VF (also known as EM5209) is a dual-channel, ultra-low resistance load switch integrated circuit manufactured by Excellence MOS Corp. Main Features • Component Type: Dual-channel load switch with N-channel MOSFETs. • Input Voltage Range: 0.8V to 5.5V. • Maximum Continuous Current: 6A per channel. • Turn-On Resistance (RON): Ultra-low, approximately 20 mΩ per channel. • Package: DFN3X2-14L (or QFN-14) with integrated thermal pad for heat dissipation. • Additional Features: • Independent on/off control for each channel (ON1 and ON2). • 220 Ω on-chip fast discharge resistor (QOD - Quick Output Discharge). • Over Temperature Protection. • Low idle current consumption (75 µA in dual mode). The UZ6 and UZ10 chips were burned out, shorting out the UT3, which is the PD controller. The TPS65994AD (UT3) is a Texas Instruments integrated circuit that functions as a standalone controller for dual USB Type-C ports and Power Delivery (PD). Main Features • Manufacturer: Texas Instruments • Function: Controls USB Type-C ports and USB Power Delivery 3.0 (PD 3.0) with integrated power supply switches. • Protocol Compatibility: Supports USB4, Thunderbolt 4 (TBT4), and DisplayPort in alternate mode. • Commercial Status: Not recommended for new designs by the manufacturer. • Packaging: 48-pin VQFN (6.0 mm x 6.0 mm). • Temperature range: -40 °C to 125 °C. • Typical applications: Reference designs for PC motherboards, laptops, and other Intel and AMD computing systems. We replaced these and, noticing that we were already experiencing voltage drop on the shorted lines, we proceeded to test the equipment, thus resolving this particular issue.