ASUS ROG STRIX GL702VSK no power issue PQ8901, PQ8900?

[ub6ib969]

PCI8701 PIN 1 Black probe = AC_BAT_SYS
PL8702 PIN 1 red probe = P_3VADSW_LX_30

measured at 20K = 7.85K

[mon2]

So that inductor and linked power rail is not the cause of this short.

Measure the resistance to ground of AC_BAT_SYS. What is the exact measurement in ohms ?

[ub6ib969]

000.3ohms

[mon2]

Would you have an adjustable power supply?

Use it to dial up 1 volt only, nothing higher, and inject it onto this power rail. The 3A-5A or more current draw will heat up the shorted part quickly. Hope it is a capacitor and not the CPU.

[ub6ib969]

I do actually. Will try this tomorrow and repost.

[mcplslg123]

When AC_BAT_SYS aka the main power rail is shorted to GND specially on gaming m/b,always first check the mosfets on vcore area. If one of the mosfets in vcore area is shorted causing short to main rail, then cpu is damaged.So before proceeding with voltage injection,do check the resistance to GND on gates of all mosfets in vcore area.

[ub6ib969]

thank you for your help I have attached a mosfet near the cpu, what resistance to GND measurements should be normal ?

[ub6ib969]

Would you have an adjustable power supply?

Use it to dial up 1 volt only, nothing higher, and inject it onto this power rail. The 3A-5A or more current draw will heat up the shorted part quickly. Hope it is a capacitor and not the CPU.

I don't have an image camera however no components are getting hot. I have the ground soldered to ground and red probe to AC_BAT_SYS.

[mon2]

How much current is being consumed by your external power supply used for this injection? Keep the voltage @ 1 volt and ok to increase the current to at least 3A but 5A+ is recommended.

[ub6ib969]

How much current is being consumed by your external power supply used for this injection? Keep the voltage @ 1 volt and ok to increase the current to at least 3A but 5A+ is recommended.

my power supply can put out more than 1A time for a better power supply.

[mon2]

We use a 'short killer' tool that claims to support upto 30A of spiked current. We set it to 0v8 -> confirm with our meter that it is indeed ~ 0v8 and use it for short circuit injection. Often at around 5-8A, the shorted tantalum / ceramic cap smokes up and/or cracks under pressure. We have fixed numerous boards this way included a 5K iMAC that other stores gave up on locally. Was a shorted bulk ceramic on the VBUS (USB) power rail.

Here is one (random) link for the tool - pretty sure we paid less a few years ago:

Short Circuit Shortkiller | Short Killer Mobile | Short Killer Phone | Locate Faults - Tool Parts - Aliexpress

An adjustable power supply with high current support should also work well.