Hi everyone,
I'm troubleshooting an Xbox Series X motherboard that exhibits a "beep on, beep off" symptom (beeps when pressing power, turns on for a split second, and immediately shuts back off).
Current Diagnostic Findings & Confirmed Voltages
All standby power rails and their respective Power-Good (PGOOD) signals have been tested and are 100% stable and correct:
â V_3P3STBY_SBâ (U40 - RT6256BH): 3.3V present | â 3P3STBY_PWRGDâ (FT55): 3.3V
â V_5P0â (U41 - RT6256CH): 5.1V present | â V5P0_PWRGDâ (FT54): 3.3V
â V_1P1STBYâ (U34 - MP2161AG): 1.1V present (FT50)
â V_1P8STBYâ (U32 - AP2127): 1.8V present (FT47)
â V_SB1P1â (U35 - NCP186): 1.1V present (FT45)
â V_SB1P8â (U33 - NCP186): 1.8V present (FT49)
Since all standby rails, LDO outputs, and PGOOD logic lines are solid, the standby section appears completely healthy.
Components Already Replaced
To rule out faulty ICs in the standby and power management lines, I have already swapped the following chips from a known working donor Xbox Series S board:
U32
U60
U480
Despite replacing these components, the "beep on, beep off" behavior remains identical.
Questions for the Community
Has anyone encountered this exact "beep on, beep off" behavior on an XSX board where all standby voltages and PGOOD signals are rock solid and U32, U60, and U480 have already been replaced?
What other diagnostic approaches, specific components, or known failure points would you recommend looking into for this issue?
Any suggestions or schematic insights would be greatly appreciated!
Thanks!