View Single Post
Old 03-25-2020, 08:29 AM   #1
dicky96
Badcaps Veteran
 
dicky96's Avatar
 
Join Date: Mar 2017
City & State: Sunny Gran Canaria
My Country: Spain
Line Voltage: 220V 50Hz
I'm a: Professional Tech
Posts: 700
Thumbs down Asus Prime Z270-P no Vcore

Hi guys

I have an Asus Prime Z270-P.

With no CPU fitted it will not start

With a Celeron G3900 CPU it starts but the CPU is cold and I have no Vcore

12V to the 8 pin molex is good, as are 12V, 5V, 3.3V to the ATX connector

Checking with a scope I have no drive to the high side gate of the Vcore MOSFETs, the gate is 0V. I didn't bother check the low side.

The MOSFET are M3054M

There is this chip uP1540P near the MOSFETs. Each high side FET has one pin of an 820R resistor connected to the gate and some of theee resistors then connect to one pin on the uP1540P but not all of them. The ones that do all connect to the same pin on uP1540P. I can't find a datasheet for uP1540P.

Also there is this other nearby QFN ASP1400BT that I think is the controller for the Vcore PSU, there look like 7 phases. But I can't find a datasheet for that either.

I do have a 1.2V supply near the DIMM slots which is probably Vram and that is running OK.

Looking for a board view plus datasheets for uP1540P and ASP1400BT plus any helpful advice on diagnosing the fault

It looks like there is a board view on a paysite which also has the MS6178 schematics I need for another repair so I may have to pay there

Cheers
Rich
Attached Images
File Type: jpg IMG_20200325_140824.jpg (938.7 KB, 15 views)
File Type: jpg IMG_20200325_140956.jpg (918.0 KB, 14 views)
File Type: jpg IMG_20200325_141022.jpg (1.11 MB, 10 views)

Last edited by dicky96; 03-25-2020 at 08:32 AM..
dicky96 is offline   Reply With Quote