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| RTX 3070 Not turning on, short on 12V Repair | |
|---|---|
| Device | RTX 3070 |
| Affects part(s) | PowerStages, Shunt resistors |
| Needs equipment | multimeter, soldering iron, soldering station |
| Difficulty | ◉◉◉◌ Hard |
| Type | Soldering |
Problem description
Fixing an RTX 3070 that showed shorts to ground on 12V from the PCIE lane and one of the 8-pin connectors. The 5V coil also seemed low (~59 ohm).
Symptoms
- Sub 100 Ohms on either 12V from PCIE slot or external 8 pin connector(s)
- Card not turning on or PC shuts off immediately after turning on
- Shunt resistor(s) likely blown
Solution
Diagnostic Steps
- This is HIGHLY likely to be a dead PowerStage/MOSFET.
- To identify which one, see Short Circuits - Repair Basics. You'll need to inject 1V and check for hotspots with either Isopropyl Alcohol or thermal camera.
- Cases like these sometimes have the MOSFET short to OUTPUT instead of GND. This means any voltage injected above 1V might damage the core.
- The best way to safely inject voltage is to connect the negative (-) lead from the LBPSU to the VCore rail, this ensures that VCore will always be at 0V and all the current will return to the PSU before reaching the core.
Repair Steps
- Replace the identified shorted PowerStage. In this particular case, 2 were shorted, first bottom one for the PCIE slot and 3rd one for 8 Pin connector.
- Check if the short is still present, if not, power up the card and measure all the voltages.
- If you're missing a voltage rail, this means there is another issue, check the device's page for more guides.
- If everything is okay, assemble the card and stress test.