• Gigabyte C246-WU4 rev. 1.0 no vcore

Forum rules:Click here to view the forum rules

  1. Topic title should contain: the device's manufacturer, full model and the brief description of problem.
  2. Topic message should contain: the PCB marking code (required in case of hardware repairs), an extended description of problem, things you have checked/replaced/measured, your conclusions and the question. If you are not able to find the PCB marking code, please read THIS TOPIC. If you still cannot locate the PCB markings, please upload a clean, both-side photos of the mainboard - it is required to remove any films, modules or brackets possibly covering these markings.
  3. Before posting a new topic please read all topics in TRAININGS subforum and make a preliminary diagnostic based on the content of those trainings.
  4. Uploading of any complete schematics, BIOS / firmware files or any other kind of documentation, or linking to 3rd party websites with such files, is STRICTLY PROHIBITED. You can only upload the small portion of documentation or, link to BIOS file on UNVERIFIED BIOS FILES subforum, which simplifies the diagnostics/repair. You are not allowed to upload more then one complete page of instruction/schematic per single topic. The file you upload must not contain any watermarks, "confidential" markings, links or email addresses and cannot be password-protected.
  5. It is only permitted to describe one faulty device per single topic - you should always open a new topic for each subsequent device.
  6. Requesting of the full schematics, BoardView files, BIOS files or any other kind of documentation is NOT ALLOWED in this subforum. If you need to ask for any of these, you should open a new topic in DOCUMENTATION/BIOS REQUEST subforum.
This topic is marked as ARCHIVAL. Please only reply if your message contains the solution (Terms and Conditions p. 12.1).

#1 Gigabyte C246-WU4 rev. 1.0 no vcore


by tretecou 8 July 2023, 13:58
Hello,
Motherboard is in very good optical condition. The problem is that vcore=0v. I checked the power of the PCH, there is no short circuit, 1.8V, 1.5V, 1.05V, 3.3V are present. The chipset gets quite hot after a while without a heatsink (60-70 degrees). The original ISL69138I chip did not previously have pwm, but vcore/vgt_pwrgd=3v, vr_rdy=3v, vrmpwrgd=3v, vcore=0v, pltrst#=0v.

At first I thought it was a bad chip, I ordered a new one, soldered it, flashed the BIOS from the original site version F5, now pwm=1.7v on all phases, pwrgd=0v, vrmpwrgd(vccst_pwrgd)=0.1v, vr_rdy=0v, vcore=0v. Vccpll, vccpll_oc, vccfuseprg = good. Vccsa, vccio are good too.

I then flashed EC=IT8795E from the x299 aorus dump, no change. The bios chip has a voltage spike on pins 5,6 (clk, mosi) when a button is pressed, after 1sek=0V. SIO IT8688E pulls vrmpwrgd up to 100 mV. When I cut the trace from the SIO to the chipset, the voltage on sio=100mV on the chipset=3.02V, and also 3V on the chipset when the motherboard is off, when I plug the sio back into the circuit, no change. PWROK comes from EC - it's 3v. The vcore voltage without cpu is 0.28v when the motherboard is off, goes to 0v and then slowly rises to 0.28v when i turn on the motherboard. The vcore/vgt_Pgood signals stay at 0V without a processor. Also, 12V dumny load circuit with Q9 resistors => very hot, 90 degrees, transistor has gate = 3V and source/drain 0V, resistance across is 60 ohm, maybe it's ok? This is the second time I see hot resistors here.
Any help is welcome. I have all the tools except the oscilloscope. The DMI tracks are ok, I checked.

Re: Gigabyte C246-WU4 rev. 1.0 no vcore


by Google Adsense [BOT] 8 July 2023, 13:58
This topic is marked as ARCHIVAL. Please only reply if your message contains the solution (Terms and Conditions p. 12.1).

Who is online

Users browsing this forum: No registered users and 2 guests

_______________________________
All rights reserved. Unauthorised copying of this website's content or any of its part is strictly forbidden.
Any trademarks, brand names, products or services published on this website belong to their legal owners, are copyrighted and used for information purposes only.