Member Avatar for kilander

I have a Dell Dimension 4550 which originally gave an error message at start up that said it could not find the hard drive. I opened up the machine and checked te connections, I see that there is power to the mother board, yet the power button is now inactive. Depressing the button results in no activity. Any suggestions.

Thanks.

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Thread shows a few different symptoms across posts: reported a storage-detection problem and then a loss of power-button response after opening the case; and suggested PSU or board faults; later observed fans and front LEDs but no POST or beeps. The sequence points to three places to check next: front-panel wiring/switch, the motherboard standby/power-on signaling, and POST-level faults (memory/CPU/BIOS).

Start with low-risk checks you can do without replacing parts. Inspect the power-switch cable at the front-panel header for broken wires or a mis-seated connector. Test the switch with a multimeter for continuity or momentarily short the two power-on pins on the motherboard (use an insulated screwdriver tip) to see if the board will start. With the main cable unplugged, measure the ATX 20/24-pin connector for 5VSB (purple) to confirm the PSU provides standby power.

If 5VSB is present but the board will not start, force the PSU on by shorting PS_ON (green) to ground (black) on the ATX connector and watch the voltages. Stable 12V/5V/3.3V rails mean the PSU is likely okay; unstable or missing rails point back to the supply. If the PSU appears healthy but fans/LEDs run and there is no POST, reduce to a minimal configuration (one known-good RAM module in the correct slot, CPU/heatsink, onboard video, no drives/cards) and try again. Fit or test a system speaker or a POST card to capture beep/LED codes. Visually inspect for bulging capacitors, scorch marks, or loose sockets.

Keep a short log of what you try and the voltages you measure. If BIOS settings are suspected or the machine boots intermittently after a CMOS reset, consider replacing the CMOS battery or consulting the Dimension 4550 service documentation before attempting a BIOS reflash. For model-specific LED/beep diagnostics and connector pinouts consult Dell Support (https://www.dell.com/support). If live-voltage checks are unfamiliar, have a technician perform the PSU/motherboard testing.

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Member Avatar for caperjack

I have a Dell Dimension 4550 which originally gave an error message at start up that said it could not find the hard drive. I opened up the machine and checked te connections, I see that there is power to the mother board, yet the power button is now inactive. Depressing the button results in no activity. Any suggestions.

Thanks.

could be a bad power supply ,no putting out enough power anymore ,and when this happens it could also destroy you motherboard ,and so on and so on !!!!

Member Avatar for jimmylong1

I have a Dell Inspiron 600m and it won't power up. I have used another power adapter that I know is good and it still will not start the computer. I am leary about opening up the laptop to investigate. Any suggestions.

Member Avatar for kilander

I replaced the power supply and it still does not power up, yet I know that there is power on the Motherboard. Any other suggestions. It was working fine previously. I opened it just to check a hard drive connection and now nothing.

Member Avatar for jimbojone

try the power cord, and possible the socket its plugged into, otherwise, its the motherboard.

Member Avatar for nancoke

could be a bad power supply ,no putting out enough power anymore ,and when this happens it could also destroy you motherboard ,and so on and so on !!!!

I am having the same problemwith a dimension 4550. I replaced DH with a new one and it worked for a little while, now it is not. It does power up and I see the abcd lights on and the fan is running. But no post and no beeps.
I did reseat the memory and the cables
???
nancoke

Member Avatar for caperjack

I replaced DH with a new one and it worked for a little while

ok,it early and it won't come to me ,you will have to tell me what is DH

Member Avatar for nancoke

ok,it early and it won't come to me ,you will have to tell me what is DH

hd is hard drive
but since then I did get is started but I have to reload the cmos since I must have wiped it out and once i had the power on it blanked out on me

nancoke

Member Avatar for caperjack

hd is hard drive
but since then I did get is started but I have to reload the cmos since I must have wiped it out and once i had the power on it blanked out on me

nancoke

it getting late and you are still loosing me,DH stands for a hard drive ?
and you had to reload the bios .?do you me you had to reflash it, or just reset to defaults .
are the abcd lights all green

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