ASUS FX505GT notebook does not turn on for repair

Machine model: ASUS FX505GT

Fault phenomenon: notebook no booting

Maintenance process: remove the bare board to observe the passive over of the bridge, 1.0 VCC is passive over, the standby current is 0.027, pressing Switch does not respond, the keyboard interface does not respond, the whole board diode value has no obvious Short circuit.There is no obvious Short circuit, 3V, 5V, 1.0V and 1.0 VCC before and after the second level convert transistor, and the isolation point of the later stage has been passive. Is it possible that the initial fault was Short circuit of Nanqiao?

Temporarily measure Diode value is normal, give me a bridge?Generation 9 CPU, sr40b bridge, pwrbtn pull-down is normal, there is an abnormal pull-down at the moment of power on, but press Switch again, there will be a normal pull-down action.

ASUS FX505GT notebook does not turn on for repair Figure 1.

ASUS FX505GT notebook does not turn on for repair Figure 2.

PM_Susb ා no output;

PM_RSMRST 3.3；

BATLOW# 3.3；

768 Crystal was normal;

VCCDSW_3P3 3.0；

DSW_PWROK 3.3；

VCCPRIM_3P3 3.3；

To change the bridge, when dismantling the South Bridge, I tried to touch the South Bridge at 210 degrees. I found that it had melted down. I took the south bridge away. As expected, there was only a circle of beads around it. The bridge was installed randomly.

ASUS FX505GT notebook does not turn on for repair Figure 3.

Replace a qnyf that you don’t know when. The chip seller says it’s universal with 40B. The standby current is 0.3-0.4-0.1-0.3, and it jumps repeatedly. Try to brush a BIOS.Test the BIOS as before!PM measurement_Susb comes out and falls. It circulates.

ASUS FX505GT notebook does not turn on for repair Figure 4.

There are two possibilities:

First, there is something wrong with my bridge. I forgot when the bridge was set, and I’m not sure if it is universal.Second, the machine does have problems, or has been made a fault.Press the bridge to check, standby 1, 05, 3, 5 are all missing.5V.

ASUS FX505GT notebook does not turn on for repair Figure 5.

3V.

ASUS FX505GT notebook does not turn on for repair Figure 6.

1V.

ASUS FX505GT notebook does not turn on for repair Figure 7.

Memory 1.2V.

ASUS FX505GT notebook does not turn on for repair Figure 8.

VCCSA.

ASUS FX505GT notebook does not turn on for repair Figure 9.

No CPU core, CPU VCC, master control 95855c VR en.

ASUS FX505GT notebook does not turn on for repair Figure 10.

There seems to be something wrong with this waveform. It’s too sharp. I feel it’s gone when I get up. VR_Enable was compared with vccsa.

ASUS FX505GT notebook does not turn on for repair Figure 11.

The en has just come out. The en has not been pulled down completely to open the vccsa, but there is no doubt that it has been unable to open the Vcore, so it can no longer open the Current protection after the Vcore.Vren is made up of CPU_VRON_CPU and PWR_Vron co provides,PAD is connected by copper.

ASUS FX505GT notebook does not turn on for repair Figure 12.

Try to cut off the vron below and boot it again. Check the drawing to find the CPU_VRON_The PWR is only connected to a jp9300, and there is no jumper point installed. It may be used as an open for test.

ASUS FX505GT notebook does not turn on for repair Figure 13.

Continue to check the source of vron. It is controlled by d6802, De_ALL_SYS_PGD_EC and PM_Susb ා if one is low, vron will be lowered.

ASUS FX505GT notebook does not turn on for repair Figure 14

Try to remove the d6802 and test vron again. But because I cut off the connection between vron and the chip, I can’t get the CPU VCC and auto power off.

ASUS FX505GT notebook does not turn on for repair Figure 15.

The measurement found that it was de_ALL_SYS_PGD_The EC did not come out. The starting current of vron connected to it reached 0.1, but cpuvron still did not come out

Replacement of EC failed.

Finally, check whether there is a ci VCC CPU in the main vcc107c, and then continue to check whether there is a ci VCC pu in the main vcc107c_EN has been published.

ASUS FX505GT notebook does not turn on for repair Figure 16.

Regardless of whether the chip is broken or not, take Parts motherboard and replace it directly.Replace u9400 and power on directly.current of change several times to 1.2. Measure that vccio is out.

ASUS FX505GT notebook does not turn on for repair Figure 17.

Let’s take a picture of booting up. The maintenance is over.

ASUS FX505GT notebook does not turn on for repair Figure 18.

The firmware exclamation mark will appear when the machine of Flying Fortress brushes BIOS. Generally, the BIOS will be updated automatically after restart. If the battery is not plugged in or the battery is low, you need to manually update the BIOS on the official website.