MSI B450 TOMAHAWK MAX 2 doesn't boot with CPU

[xfor62]

Hello,

i'm new and come here because i need help to try to repair a mobo for my nephew.

He bought msi b450 tomahawk max 2 but this board doesn't boot with a CPU on the board.
Even, if the CPU is on the board, the LED system blink and never boot.
Without he CPU, the board goes ON and the voltage seems good.

I just have a doubt on SYS_FAN4, i have the next voltages 0V (pin 1), 12.12V (pin 2), 10.7V (pin 3) and 5V (pin 4).
All others Fans (sys/cpu/pump), i have on pin 2 : 6,3 V, others voltages are the same as above.

can anybody say me if those voltages are corrects or not for each fan in particular on pin 2 for sys-fan 4.

As the problem is occurring when i put the CPU on the board , and i have not for the moment another CPU, i'm trying to check if the board is ok by testing voltage.

thanks in advance for your help

[xfor62]

Test | ATX...... | CPU (EPS.12V). | CPU............. | RAM............. | Result............... | EZ.LED.On............. | LED.Off
1... | Connected | Not connected. | Out of the board | Out of the board | OK, good voltages.... | CPU................... | RAM/VGA/BOOT
2... | Connected | Connected..... | Out of the board | Out of the board | OK, good voltages.... | CPU................... | RAM/VGA/BOOT
3... | Connected | Not connected. | On the board.... | Out of the board | KO, variable voltages | RAM/VGA/BOOT blinking. | CPU
4... | Connected | Connected..... | On the board.... | Out of the board | KO, variable voltages | RAM/VGA/BOOT blinking. | CPU
5... | Connected | Connected..... | Out of the board | On the board.... | OK, good voltages.... | CPU................... | RAM/VGA/BOOT


so i think the CPU is causing the boot problem.
We have tested the RAM in another motherboard, and the RAM works.

[foshland]

Have you tested the power supply in another pc? maybe its the problem....

[xfor62]

Hello,

no, it's a new i bought this week, it's a cooler master mwe 550W bronze.
i had previously a noname PSU and i've doubt about this noname PSU, this is why i bought a new one PSU with a known brand name.

So i hope, it's a good one.

[xfor62]

I checked voltage at different points on the MB and found nothing wrong (with CPU out).
ATX Voltage OK
DDR voltage 1.2V OK
USB 5V OK, i plug a smartphone and it is charging
USB flash is ok because we can use flash button to update BIOS (around 7 minutes with a ROM file from MSI website)
BIOS voltage 1.8V OK

So i will look at cpu parts

if somebody has bdv file for B450 Tomahawk Max 2 (boardview file) because i have only schematics view

[Benass]

Please consider updating bios, There is a small chance your bios do not support the cpu. ( I might be wrong)

[DynaxSC]

Have you checked also the 0,6V memory voltage ?
Correct CPU generation for this board ?
Can you check the CPU on another board ?
CPU socket pins are OK ?

[dicky96]

Do you have Vcore when the CPU is fitted?

Could you post the schematic here please, I don't have that one.

Thanks
Rich

[xfor62]

Originally Posted by Benass

Please consider updating bios, There is a small chance your bios do not support the cpu. ( I might be wrong)

Hi,
i've done it, without issue (around 7minutes)

And from MSI website, the CPU Ryzen 5 3400G is marked as compatible

thks

[xfor62]

Originally Posted by DynaxSC

Have you checked also the 0,6V memory voltage ?
Correct CPU generation for this board ?
Can you check the CPU on another board ?
CPU socket pins are OK ?

i will check voltage.
CPU generation is correct for me, Ryzen 5 3400G
I didn't have another board for the moment
CPU socket seems ok, but i didn't disassembly it

[xfor62]

Originally Posted by dicky96

Do you have Vcore when the CPU is fitted?

Could you post the schematic here please, I don't have that one.

Thanks
Rich

please find schematics in attached file

[xfor62]

without CPU, under the socket, i found on different points either 1.1 v either 1.2 v

[xfor62]

Hello,

few news, i've tested an athlon 3000g and all works fine.

So the default is the CPU.

MB, RAM is ok

[xfor62]

Hello,

i've tested CPU, and short between ground and vddcr_cpu, vddio_mem, vddcr_soc .....

CPU is dead....

Regards