Compaq Deskpro P733 motherboard problems with unusual PSU performance
Compaq Deskpro P733 motherboard problems with unusual PSU performance
Hey there. I own an old Compaq Deskpro EN P733. My motherboard failed recently, so I tried swapping it with a similar one I bought earlier—it came with a case, which I thought was useless. But the new board worked surprisingly well. At first, it reported that the CMOS battery was dead even after I replaced it, but then it stopped. I managed to install a brand-new Windows XP, and initially everything seemed fine: network controller and audio were active. Now I’m facing a new problem I’ve never seen before.
1. When I connect the power supply and turn it on, it starts right away. The HDD and CD drive aren’t getting any power. But the fan connected to the GPU in the AGP slot is running. Any fan linked to the CPU header isn’t working. The board has power but isn’t turned on—just like it should when plugged into a PSU.
2. Pressing the power button triggers a reset, and the BIOS shows no errors. The HDD and CD drive have power, and I boot into Windows. The fan on the CPU header still doesn’t work. Over time, the system appears to be under heavy load, causing fans to speed up.
3. If I press the power button while in Windows, the system powers down instantly with no smooth shutdown. The PSU restarts immediately, and the board goes through another reset cycle. After a short wait, it restarts again, and the system returns to its usual state. When the PC is on, the power LED flashes red as per the manual—indicating a "ROM error."
I tried to boot from a floppy drive, but the update process freezes, suggesting a possible issue with the floppy or the ROM error. I’m unsure if this is due to a corrupted BIOS or a physical fault. The board looks clean, has no visible damage, and uses the proprietary Compaq socket 370 with an Intel 810 chipset.
I’ve attached a photo of the motherboard and some video clips of the behavior when powering on and off. Any advice would be greatly appreciated!