Computer Running for 4 seconds

[fbaribault]

Hi, wondering if anyone could help me with this?

A friend gave me is Compaq 4420CA 1.4 ghz, 128 mb ram. Really basic
machine. Said it wasn't working and that he took it to a shop who said
would cost 200$ to fix so he bought another one.

I took it apart. PS was fried (a diode was broken and burnt). So I
bought another PS, a Sparkle Power Q 300W ATX Power Supply 80mm fan 13A
12V.
I've put it in and toggle the PS switch to ON after plugging it. The
computer started without the need of pressing the front switch and ran
for maybe 4 sec or less. No post sound.

Made a few search on the internet and tried the following:

1. Disconnected all component, modem, drives, IDE cables, front switch,
front LEDs.
(graphic card is integrated)
Result: No change.

2. Removed the memory and CPU
Result: Now PS shuts down after only a second or so.

Anyone has any idea.
Thanks

 

[Mike T.]

Hi, wondering if anyone could help me with this?

A friend gave me is Compaq 4420CA 1.4 ghz, 128 mb ram. Really basic
machine. Said it wasn't working and that he took it to a shop who said
would cost 200$ to fix so he bought another one.

I took it apart. PS was fried (a diode was broken and burnt). So I
bought another PS, a Sparkle Power Q 300W ATX Power Supply 80mm fan 13A
12V.
I've put it in and toggle the PS switch to ON after plugging it. The
computer started without the need of pressing the front switch and ran
for maybe 4 sec or less. No post sound.

Made a few search on the internet and tried the following:

1. Disconnected all component, modem, drives, IDE cables, front switch,
front LEDs.
(graphic card is integrated)
Result: No change.

2. Removed the memory and CPU
Result: Now PS shuts down after only a second or so.

Anyone has any idea.
Thanks

Sounds like the power supply that died damaged the mainboard or CPU,
lso. -Dave

 

[job]

I remember on some motherboards,that not having the CPU fan connected to the
motherboard would triggere a shutdown after 4 seconds.Or if the three wire
fan was replaced with a two wire fan.

 

[DaveW]

The fried PSU probably destroyed the motherboard at the time of its failure.
Inexpensive PSU's with poor internal protection circuits frequently do that.