Hi All,

My Precision Tower 3620 was humming along yesterday and the then all of sudden it wasn't. It no longer does anything in response to the front-panel power switch. If I push the little black momentary switch at the back of the power supplier, the green LED lights up and stays lit as long as I hold the momentary switch closed. The green LED goes out as soon as I release the momentary switch.

The power supply is a model HU365EM-00 (Dell P/N 7VK45). The "UP/N" is HK465-11PP.

I disconnected the power supply from the computer and tested the various outputs using a paperclip to hold closed the momentary switch on the back of the PSU. With the momentary switch closed I get the following voltages at the three PSU output connectors (relative to black wires/PSU chassis):

P1 White wires: +12.25V

P1 Purple wire: +11.54V

P1 Gray wire: +4.85V

P2 Yellow wires: +12.25V

P3 Brown wires: +12.25V

I have not tested the power supply with it connected to its respective loads (i.e. the motherboard).

If the problem turns out to be the power supply, it appears to be "in-stock" at several outlets (including a few Ebay sellers), but these suppliers who carry it look a bit dodgy. This makes me think that I am foolish not to keep a spare PSU on-hand for just such emergencies. Of course, that assumes the problem is in the PSU.

I don't have a good understanding of how the momentary switch on the front-panel of the computer interacts with the PSU to "latch" the on state. Nor do I know if the momentary switch on the back of the PSU is supposed to latch the on-state in a similar manner to the way the computer's front-panel switch latches the on-state.

Since the front-panel momentary switch connects to the motherboard and not directly to the PSU. I am thinking that there is some circuitry on the motherboard that plays a part in the PSU on-state latching process, but I am hoping that the problem is confined to the PSU as I don't relish the thought of having to replace the motherboard.

Any helpful suggestions would be appreciated.

Thanks!