Problem with the old CPU failing to start after replacing the new one.
Problem with the old CPU failing to start after replacing the new one.
I've been using this PC for about five years and it functioned perfectly until recently. A few days back I planned to upgrade my CPU from a Ryzen 3 1200 to a Ryzen 5 3600XT, but it arrived damaged—several bent pins. After carefully bending them back, I installed the new CPU, but the motherboard lit up with white light. No major issues, just returning the damaged one and putting the old CPU back in. Now the Ryzen 5 1200 is inside, but it won’t boot properly; both CPU and DRAM lights are on. I tried removing the CMOS battery, re-seating it, and using a single RAM stick, but the same error persists. Help would be greatly appreciated as I need this working soon.
I'd check the R5 1200 pins once again, just in case. Since it could be possible that one of the pins broke off from R5 3600XT and got stuck inside CPU socket, whereby when you installed R5 1200 into it, it pushed the pins sideways (due to the blockage inside CPU socket).
Other reasons include actual (internal) damage for MoBo CPU socket. Broken off pin can damaged the MoBo as well. New, known to work MoBo would show if your R5 1200 is sound or not.
3rd option is that ESD killed your MoBo. Not that unheard of, especially when you don't have active grounding when working with PC internals.
I've verified the R3 1200 pins and they appear to be correctly installed. Regarding the R5 3600XT, there are no missing pins visible. The issue is that with the R5 3600XT, only the CPU light was on, and I didn't mention it had a continuous beep, whereas with the R3 1200, both the CPU and DRAM lights were active. It's possible that if the pins were bent, both would show the same error, though I'm not sure.
At this stage, I'd consider using the second MoBo. The likelihood that both CPUs are bad is low, particularly because your R5 1200 functioned properly before. If you don't have a compatible second one nearby, take your PC to a repair shop and cover the costs of diagnostics and repairs.