@Gregor
I lost my X5000/20 (one of the beta boards from 2015) 3 years ago with same MCU problem. It was sent to UK, AmigaKit was unable to repair it.
It might be a good idea to connect a MCU debug cable and check what is going on:
Mine X5020 debug output was:
Cyrus Plus
MCU Firmware Version 2.1
Hardware Version 2.1
CPLD Version 2.0
CPLD build time: 10:10:10
CPLD build date: 2014-05-27
MCU build time: 10:34:25
MCU build date: May 30 2014
SYS CLK frequency 133MHz
Dual Ethernet devices fitted.
P5020 processor fitted
>> Power up request detected
Enabled PS_ON
ERROR: vdd_ca out of range. Expected 1.10, got 0.86
WARNING: Supplies Turned off. Shutting down.
ATX supply turned off.
ERROR: vdd_1v0_xorro out of range. Expected 1.00, got -0.00
WARNING: Supplies Turned off. Shutting down.
ATX supply turned off.
- vcc_cpld: 3.33
- vdd_3v3_xorro: 1.32
- vdd_1v0_idt: 0.00
- vdd_1v0_xorro: -0.00
- vdd_3v3: 1.09
- vdd_2v5: 0.08
- vdd_1v2_eth: 0.32
- vdd_pl: -0.00
- vdd_ca: -0.00
- vdd_cb: -0.00
- vdd_ddr3_io: 0.41
- vdd_xvdd_fl: 0.14
....
....
ERROR: CLKGen1 failed to configure!!
Initializing clocks failed please re-power the board.
WARNING: Supplies Turned off. Shutting down.
ATX supply turned off.
Please check this thread:
https://www.amigans.net/modules/newbb/viewtopic.php?topic_id=9415