PS5 EDM-020 no UART, standby voltages okay

Ruts · June 13, 2026, 8:10pm

Hi

I’m working on a PS5 EDM-020 motherboard.

When supplying 12V to the board, the current consumption initially jumps to around 50mA, then quickly drops to about 6mA and stays there.

When I first started working on this board, the DA9065 was not producing 3.3V, so I replaced it with an RT5126. After the replacement, all standby voltages are present and no fuses were (or are) blown.

Since this did not solve the issue, I attempted to use UART, but I cannot get any communication. Both TX and RX lines have 3.3V present. So I taught maybe Southbridge is faulty, I tried two different Southbridge ICs, but the behavior remained unchanged and UART is still non-functional.

I checked that standby voltages around the HDMI IC and Wi-Fi module are present.
Using a thermal camera, I can see a very faint warm spot on the Southbridge.

Has anyone encountered a similar fault on an EDM-020 board or have suggestions on what I should check next?

Any help or advice would be greatly appreciated.

Thanks!

Calvin · June 14, 2026, 7:34am

Are there any signs of life, blue light for a second, beeping at start button press?

Ruts · June 14, 2026, 1:12pm

Nope, no lights or sounds.

Calvin · June 14, 2026, 1:35pm

I would make a dump from the BIOS and check for error codes at offset 0x1c5000.

Ruts · June 14, 2026, 3:44pm

0x1C5000 00 07 0F 07 00 03 0C 04
0x1C5010 00 07 0F 07 00 00 00 04

Calvin · June 14, 2026, 4:33pm

The first UART error string starts at 0x1C5100
In the posted image 0x1C5100 = 80 20 80 80 → UART error 80802080

Ruts · June 14, 2026, 7:20pm

Thank you for the useful info! I wasn’t aware that the error codes could be read this way from the BIOS dump.

As I am unable to attach photos to the post I will add the lines as text

0x001C5100 01 00 81 80 FF FF FF FF 00 00 FF FF 00 00 00 00
0x001C5110 77 21 00 00 00 00 00 00 FF FF FF FF FF FF FF FF
0x001C5120 03 03 0D C0 FF FF FF FF 00 00 FF FF 00 00 00 00
0x001C5130 77 21 00 00 00 00 00 00 FF FF FF FF FF FF FF FF
0x001C5140 03 03 0D C0 FF FF FF FF 00 00 FF FF 00 00 00 00
0x001C5150 77 21 00 00 00 00 00 00 FF FF FF FF FF FF FF FF
0x001C5160 01 00 81 80 FF FF FF FF 00 00 FF FF 00 00 00 00
0x001C5170 77 21 00 00 00 00 00 00 FF FF FF FF FF FF FF FF
0x001C5180 03 03 0D C0 FF FF FF FF 00 00 FF FF 00 00 00 00
0x001C5190 77 21 00 00 00 00 00 00 FF FF FF FF FF FF FF FF
0x001C51A0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

Error Code: 80810001
Cause: General Power Failure (Peripheral, GDDR6, APU, Data Line Short)

Should I assume the worst and suspect a faulty APU? Or are there still other areas worth investigating first?

Calvin · June 14, 2026, 8:09pm

C00D0303 = PMIC access error

I would check at SB PMIC (DA9065/RT5126) pins 14 (SCL) & 15 (SDL):