Replace power supply for m9400f

[r3tir3d3d]

Reading some advice I found in community forum that the problem of not being able to start my computer is that the power supply needs to be replaced. The power supply is 350W for a micro ATX card. The fan has to exhaust through the back. I see no PS connections for the CPU (2.4GHz AMD Phenom X4 9750 Quad-Core Processor). But the power button is on the top, front of the case, it is not part of the power supply.
The current PS has HP P/N: 5188-2859, [edit] 05, made by Delta Electronics Inc. etc.

Can I replace it with any ATX power supply that has the exhaust fan out the back and supports at least 350W power and fits? Can the power switch on the top, front of the computer be disabled and instead use the power switch on the back of the PS?

Is it possible the micro switch used by the power switch may need to be replaced instead of the PS?

Where do I find new replacement parts?

[old_geekster]

@r3tir3d3d , welcome to the forum.

Here is an upgraded version of the original power supply unit (PSU) in your computer:  https://www.ebay.com/itm/New-PC-Power-Supply-Upgrade-for-HP-5188-2859-Desktop-Computer-/222041071489

It is 400W.  I would contact the seller to see what they have to say about it.  This way you can use the power switch on the computer.  It is not recommended to use the power switch on the PSU to turn the computer on and off.

What is your computer doing?  If you give me some of the symptoms I will try to make certain that it is the PSU that has failed.  Since the computer is almost 12 years old it is very likely that it is the problem.  The PSU is the most replaced component in a computer.

[wb2001]

@r3tir3d3d,

While there were 2 different motherboards issued to the 9400's, here is an example. 

The CPU power plug is  the seven O'clock position from CPU chip.

[r3tir3d3d]

The first time I had the problem I pressed the power on button on the case but the computer would not start, the button would not turn blue, and there was no sound coming from the computer. So I pressed and held the button down for a long time, and when I gave up hope I released the power button, the button light lit and the computer actually booted. This is why I thought there was possibly a problem with the micro switch which the case button depresses. I the next time I could never get it to start again. I found the HP Community Support blogs. They talked about the green led on the power supply (PS). I then started looking more closely to what was going on. >Now when I pug the computer in the green (PS} led lights. When I push and release the power button nothing happens, but the green led stays lit, even after several times in a row. If I hold the power button down for a while the green led goes out. If I unplug the computer and push and hold down the power button the green led lights, then goes out. Now the computer appears to be in the same state as described in sentence > above. In my original statement I said I saw not PS wires going to the CPU. What I meant is all wires from the power supply appear to either plug directly into peripheral drives or the motherboard (MB). I still might be wrong. I have only removed the side case panel and the plastic front. I can see much but not all of the top of the MB. I have not removed anything else. I have tried to figure out who made the MB and what it is. It is plainly written that it was "made in China". Painted near the center of the MB in large block letters is "M2N68-LA", however printing is block letters so it is difficult to distinguish if the "M2" is really an "MZ" and the "68" is not a "6B". There are stickers on the MB, two have "P/N: 5189-1661", if this helps.

[r3tir3d3d]

I read both responses and but did not pay full attention to wb2001(Level 15). Thanks, I now know I have a NARRA3-CL8E motherboard.