Dell dimension 4550 not powering on

I have a old dell 4550 and it will not turn on.It uses all ribbon cables and i have tired everything.I know it is not the power supply because there is a green light on the mother board when i apply power so i need help asap to fix this thanks.

mikeymaiden

The green LED on the motherboard, is the 'Standby' Power Light, aka 'Flea Power', this only indicates that +5VFP power is reaching the motherboard and does not indicate the power supply does not have issues.

Is the power button LED, solid green, blinking green, solid amber, blinking amber, or off?

Check the sequence of the DIAGNOSTIC LIGHTS on the back panel of the case. See page 60 of the Owner's Manual

ftp.dell.com/.../dimension-4550_Owner's Manual_en-us.pdf

Bev.

well there is no light on the  power button it simply will not turn on

MIKEYMAIDEN

Power button not lite could indicate either, a bad power supply, or a faulty power switch.

Are any of the four diagnostic lights lite, if they are, what is the sequence of the lights, located on the back of the case?

Bev.

STARTECH  ATXPW400DELL  is for

http://www.tigerdirect.com/applications/searchtools/item-Details.asp?EdpNo=4276627

Dimension Series Models: 1100 / 2200 / 2300 / 2350 / 2400 / 4300 / 4400 / 4500 / 4550 / 4600 / 8200 / 8250 / 8300 / 8400 / B100

Optiplex Series Models: 170L / GX60 / GX150 / GX240 / GX260 / GX270

Power Edge Series Models: 400SC / 600SC

Precision Workstation Series Model: Model 340 / 350

Smart Step Series Models: 100D / 150D

You need specific power on the 3.3v and 5v rails NON PFC for this to work.