Z400 Workstation

[chriss232]

I have an issue with starting my pc, I've recently torn apart this z400 I got from a friend and I'm currently reusing it with the power supply (original delta electronics because the atx ones arent compatible), mb, ram and cpu in a different case.

The problem is that: The 24/atx (It's different, forgot the naming) will not work in combination with the cpu power connector, if I plug both in, a green led blinks at the top left of the motherboard, and thats it: no fan spin, no psu light, nothing.

As soon as I turn off the pc and remove the 24 pin and turn it back on it works just fine, as in. The cpu fans spin, the psu light and fan come on. and it receives power accordingly.

I do not know whether or not the issue lies with the psu or the motherboard, does anyone have an idea?

Greatly appreciated 

[Kuroi_Kenshi]

Hi @chriss232,

Welcome to the HP Support Community!

I understand that you're reusing the components from an HP Z400 Workstation in another case, and the system powers on when the main motherboard power connector is disconnected but does not start when both the main power connector and CPU power connector are connected.

Since the Z400 uses a proprietary power supply and motherboard power configuration, please try the following:

• Disconnect AC power and remove the main motherboard power connector and CPU power connector.
• Check both connectors carefully for bent, damaged, or burned pins and make sure there is no debris or loose connection.
• Reconnect the CPU power connector first, making sure it is fully seated.
• Reconnect the main motherboard power connector and make sure it is also fully seated.
• Remove any non-essential components, including additional PCIe cards and USB devices, leaving only the motherboard, CPU, one RAM module, CPU cooler, and power supply connected.
• Try powering the system on again.

If possible, test the motherboard with the original Z400 case/front-panel power connection, since the power switch and front-panel wiring may differ when the components are moved to another case.

The fact that the motherboard LED lights when both power connectors are connected but there is no fan movement suggests that the system is receiving standby power, but it is not completing the power-on sequence.

If the system still behaves the same way with only the minimum components connected, the next step would be to determine whether the issue is with the power supply, motherboard, or CPU power circuit. Avoid repeatedly powering it on if you notice any burning smell, unusual heat, or visible damage.

Please let us know what happens after testing with the minimum hardware configuration.

Take care and have an amazing day!

Best regards,
Kuroi_Kenshi