VivoBook F505/X505

Fig. 1

Fig. 2

Fig. 3

Asus VivoBook F505 no RAM voltage

Problem

Solution

VivoBook F505 no RAM voltage

The machine is equiped with X505ZA 2.0 motherboard. The same board may be used in other VivoBook models. Found missing CPU core voltage. All previous required voltages OK, but missing RAM voltage; 1.2V not present at corresponding power coil. See Fig. 1. Inspecting opposite side of the board, corroded resistor with broken trace found. Result to be TON line of RAM voltage controller. See Fig. 2. No schematic, nor boardview available for this motherboard (at the moment). As usual value fort such resistor is in range of 180-620K, I choosed 560K. Using 0603 size helped me to bypass broken trace also. See Fig. 3 Once correct RAM voltage appeared, CPU core voltage comes on too. Motherboard came back to life.