Poweredge 1750 Power source

Hi. I have a DELL PE1750 with one PSU. I have tried without any luck to put another PSU in. I have 2 brand new PSU’s and no matter which one i put in the red light comes on and after 2-3 minutes goes off but the power source won’t start. it only lights on the green light for power presence.
I have also tried to put the two new ones in and both red lights came on when i pushed the power button stayed on for like 2-3 minutes and both off. the power presence green remained on but just them.
Did anybody experienced this problem? is there a way around it? could there be something broken or it needs an update of any kind? I have updated the firmware to the latest.