Base Voltage Rail Short on Pascal GPUs

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Got a short on 12 V or 3.3 V rail? You've come to the right place!

12V_BUS Short[edit | edit source]

Symptoms:[edit | edit source]

  • Sub 100 Ω on the 12V_Bus rail.
  • Computer won't power on or instantly shutting down upon pressing the power button.
  • Fans not spinning (in case of blown fuse).
Possible shorts on 12V_BUS (Figure 1)

Above (Figure 1), you can see all the possible components that are able to short the 12V_Bus rail.

12V_EXT Short[edit | edit source]

Symptoms:[edit | edit source]

  • Sub 100 Ω on the 12V_Ext rail.
  • Computer won't power on or instantly shutting down upon pressing the power button.
Possible shorts on 12V_EXT Pascal (Figure 2)


When a short occurs on a 12 V line, the first thing that you should check is the powerstages/VRMs. They are the the most likely to fail due to overheating.

The other components that you should check are capacitors. Capacitors can fail closed sometimes, causing a direct short between the rail and GND.

A less likely but very possible scenario for 12V_Bus would be the 5 V controller (Figure 1)

3.3V_BUS Short:[edit | edit source]

Symptoms:[edit | edit source]

  • less than 100 Ω on the 3.3 V rail
  • No other minor rail turns on

3.3 V isn't used to feed power-hungry components and therefore is very unlikely to short, but if it did here is where you should look:

Possible shorts on 3.3V Pascal (Figure 3)

Repair:[edit | edit source]

To find the component that's causing the short you need a lab DC power supply and some freezer spray or isopropyl Alcohol (or a thermal camera).

Step 1: Injecting voltage[edit | edit source]

Start by applying 1 V through the shorted rail using a DC Lab PSU and measure the voltage across Vcore, Vmem, and 1.8V rails. If the voltage going through is less than 50 mV, then you can apply more voltage to the 12 V rails without worrying about killing the GPU core or memory. However, if the voltage going through is more than 50 mV, you need to remove all the inductors going to the core and memory to protect them from high voltage.

Step 2: applying alcohol or freezer[edit | edit source]

Apply freezer spray or alcohol on the suspected components while the power is still connected. The faulty component will heat up causing the alcohol or the freezer to evaporate.

Step 3: Removing the shorted component[edit | edit source]

After identifying the shorted component, remove it and check if the short is still there. If there is still a short, repeat step 1.

otherwise, replace it and test the card.