Short on Base Voltage Rail on Turing GPUs Repair

Problem description
When the card is not turning on at all, causes the entire computer not to turn on. Caused by a shorted component on 12V or 3.3V rail.

Symptoms

 * Sub 100 Ω on the 12V_Bus, 12V_EXT, or 3.3V_BUS.
 * Computer won't power on or instantly shutting down upon pressing the power button.
 * Fans not spinning (in case of blown fuse).



Diagnostic Steps
How to find short circuits
 * Identify which rail is shorted by measuring the resistance of each. Turing GPU Diagnosing Guide here you can find points to measure from
 * Inject 1V 10A to the shorted rail
 * Check with thermal camera or isopropyl alcohol for hotspots, all possible shorts are in the attached photos.
 * In the case of 12V short, make sure to measure VCore voltage while injecting, if you read any voltage higher than 0.1V then a MOSFET is likely shorting 12V to the GPU then to GND.
 * If this is the case, remove the ground power supply lead and connect it to VCore. Then identify the shorted MOSFET/Power Stage.

Repair Steps

 * After the shorted component has been identified, remove it.
 * If the short is still present, repeat the diagnostic steps until you find the other shorted component.
 * If the short is gone after removing the component, replace it.
 * In the case where the shorted component was a MOSFET and after replacing it shorts again immediately, replace the controller/driver for this MOSFET.