Asus FX505DT

[Lukosiukas]

Hello, i need to identify a component. Computer do not turn on, this is getting extremely hot. No schematics or board-view available.
Markings on chip is :
W27
8

[Lukosiukas]

up, i dont want to pay 600euros for new motherboard

[xweb]

same problem here... did you solve?

[reformatt]

I've just had one of these boards machines come through. The power adaptor immediately shuts down when connected.

Located the fault with voltage injection and thermal camera. The area in question by the OP is for CPU Vcore, and in my case was the AOE6932 dual FET to the left. Only one of the internal FET's had shorted, the other was ok. I usually find a dead CPU at the end of this scenario. The CPU measured a little over 1.2 ohms so I was not confident. But at least it wasn't a dead short. I didn't have a replacement at the time, so I took it off the board and saw what the other phase would do. Surprisingly I got 1V. Machine wouldn't fully start because of the missing phase, but there was hope.

So ordered it, and finally fitted the replacement AOE6932 today and machine is working fine. I have to assume the FET that shorted was the low side FET, not the high side as the CPU survived. I took the liberty to measure some volts on the coils for future reference. A little over 1 ohm seemed a little too low fpr Vcore, but there you go.

[caspian]

Thanks,
Is there any hot Mosfet now after the replacement?
How much hot is the CPU now?

[trepachka]

Hello, my motherboard is also Asus FX505DT. However, the boardview I have is for a different revision of this motherboard. I need help identifying both capacitors that are not part of the boardview I have and also appear to be shorted. There are several faults with this motherboard. I removed the super I/O chip and that short is gone. However, these two capacitors are also shorted. I am afraid the GPU is dead as result. Thanks in advance.

[Bonzas]

Originally Posted by trepachka

Hello, my motherboard is also Asus FX505DT. However, the boardview I have is for a different revision of this motherboard. I need help identifying both capacitors that are not part of the boardview I have and also appear to be shorted. There are several faults with this motherboard. I removed the super I/O chip and that short is gone. However, these two capacitors are also shorted. I am afraid the GPU is dead as result. Thanks in advance.

Maybe this

[Stevedb]

How much resistance do you have. It is normal to have low resistance there it can be 1 ohm or so on newer gpu core

[Stevedb]

I think it is jut low resistance and not a short.how much resistance do tou have to ground?

[trepachka]

I am new to this and took the beep coming from my multimeter as a short. The resistance measures 3.2 Ohms. I am also attaching the image from the backside of either GPU or CPU (I am not sure which is which). Most of those capacitors also read about 3 ohms.

I definitely removed the short when I took out the super I/O chip IT8987E/BX.

A question: does this chip require reprogramming or can I just purchase one on eBay or any other place as long as the markings on the chip match?

[mcplslg123]

Yes, IT8987E is programmable but with asus it'll program itself on 1st boot. Make sure the suffix after IT8987E matches.

[trepachka]

What about the resistance value on those capacitors I had mentioned? Is it expected for the resistance to be around 3 ohms? All mosfets I checked are OK. The main power rail is present but that's about it. No other voltage is there. That's why I tested the capacitors around the controller chip and they were all shorted to ground. I am ordering a new controller chip. I am hoping that was the problem.

[mcplslg123]

Hey man, dont mess with those caps. These are low voltage rails and caps here could show as low as 1-2 ohms and that cant be considered short.

[trepachka]

After replacing IT8987E, I also found another fault with bq24780S chip. It was replaced as well and now I get 5v, 3.3v and 1.8v power rails. However, on power up, computer keyboard flashes keys non-stop and the notebook is not charging. Checking battery charging pin I only get 2.5v vs. 10v+ expected.

I am just wondering what my next step should be.

[mcplslg123]

Locate the 2 dc-in mosfets and then measure voltage on pin1-4-8 of these fets and report back. Also mention the voltage on all pins of battery connector(without battery )