msi mpg z390m gaming edge ac missing voltages and wont turn on when pressing the power button

[redbomb65]

hi i have a msi mpg z390m gaming edge ac mb. that wont turn on when i short the 2 pins on the front connectror.
im new in electrionic repair. and i hope that someone will share a bit knowledge, thoughts or ideas with me and others, to repair that damm thing ;D
1. thought psu problem. nope psu is good. i even bought a psu tester to be save.
2. thought a short somewhere that the psu goes in short save mode. nope... no short to measure with my multimeter to ground. psu and mainboard starts with all cabels plugget in, when i bridge green and black on the 24 pin.
cpu isnt getting hot, and my dbug card shows 00 on the display. if i remove the bridge between green and black, the board and the psu turns off.
i noticed the little plus symbols all over the board. but i cant measure voltage at some of them. did someone had such a problem or a schematic what voltages i should have at these points?
im glad and hope that someone can help me with that problem.

[McWhitePink]

Please check the voltage on the power button pin, should see voltage above 3.3v. That's the first one you should check.

[redbomb65]

hi, thanks for your reply.
jup 3.3 volts are present on the power button pin. and 5 volt at the usb port and the usb connectors. my thought: maybe there is a problem with a bad cap, mosfet or resistor at the chipset.

[McWhitePink]

You'd better to look at the repair guide, follow the power sequence and check each voltage. It's not that simple.

[redbomb65]

wait `what? there is arepair guide for that board? can i ask you where i can find that guide?

[McWhitePink]

The intel power sequence is pretty much the same. Check any motherboard repair guide for intel chipset

[redbomb65]

hmmm........... the most repair guides that i can find are beyond a paywall to read them. i searched on google: intel power sequence motherboard repair guide. and found only some vids from indian with some bad pictures. like that: https://www.youtube.com/watch?v=m0_aaMV45hY
but when it is correctly what he says i might be able to find the probem. i marked red, what i undertand coud might the problem or between it. green marked is the area that is a bit bent down. maybe the chipset hasnt a good connection anymore. i will test some voltages and try to reflow the chipset.
please correct me when im wrong. ist my first try to troubleshoot a mb ;D

[McWhitePink]

https://www.badcaps.net/forum/troubl...c-repair-guide

this is an example of RG.

[redbomb65]

hi little update here. i think the sio chip is not defekt, i think the pch is the problem. i have the z390 and a z290 board. and if i messure the pch i have 29 ohms. the other board ist 82 ohm around the pch. (z290) i think the board is not repaireble with my skill level, because i dont know if im correct, i dont know the values oft he caps or resistors or the ohms for the pch. and i dont wanna buy a new pch, if i dont know if im right. if someone has any ideas please let me know.

[DynaxSC]

Check the voltages on chipset if they are present, easiest to do this is on the caps which are on the chipset, the inner pads are always the positive voltage, the outer pads are ground, but use a ground pad eg. in the 12V ATX connector. You should have 3 voltages present in stand-by: 1.05V, 1.8V and 3.3V. If some is missing measure the resistance of that power line (board disconnected from PSU), if you find near 0 ohms, or 0 ohms, 99% the chipset is gone. For the Z390 1.05V line 20-70 ohms are normal, the other lines should have resistances in kohm range.

For replacing chipset you need a hotair station with preheater. Replacing a chipset is very difficult, if you never done this, you will most probably fail plenty of times before first success. If first attempt is not successful, which is almost sure, you will need to reball the chipset, for which you need additionally solder balls, stencil, and a fixation tool. You may destroy the pads on the motherbord, solder the chipset, but with shorted pads/balls, destroy the chipset or board with too much heat, do not manage to solder all junctions of the chipset to the board pads, etc. You need to care about correct temperatures, use a good enough solder fluid, handle somehow the thermal deformation of the board, protect plastics from heat, etc. Finally a completely new chipset must be programmed with the firmware (Management Engine) otherwise the board may not work correctly. Better let it do somebody with professional experience.

[redbomb65]

thanks, jep the chipset is definitely dead, the sio is sending the correct voltages to start the chipset, all needed voltages are present too.