My PC stopped booting properly after waking from sleep: the fans turn on, but it never reaches POST. The system uses a B850I Lightning motherboard and an AMD Ryzen 5 7600X. A repair shop tested the CPU in both my motherboard and another board and said it would not POST, while their test CPU worked in my motherboard. That suggests the CPU may have failed, even though it is only about 18 months old.
However, they also claimed the motherboard had been mounted with incorrect screws and that they had reinstalled it using different screws and washers. I built the system myself and used the screws supplied with the motherboard. They additionally said part of a USB cable was stuck in one of the ports, but none of my cables are missing a connector end. I was charged $132 AUD and received little help getting a quote for a replacement CPU; they instead suggested buying one from another local shop.
The motherboard and most other components are still under warranty, but the CPU was purchased through AliExpress. I do not want to buy a replacement CPU only to discover that the motherboard or another component is actually faulty. What would be the safest way to confirm the diagnosis?
4 Answers
The best next step is an independent second opinion, preferably from another reputable repair shop or by testing the CPU in a known-good compatible motherboard. A failed CPU is possible, but the symptoms could also involve the socket, motherboard, BIOS, power delivery, or mounting pressure. If you buy a replacement locally, keep the receipt and confirm the return policy so you can return it if the original CPU turns out to be fine.
Motherboard mounting screws generally do not require washers. The screws and case standoffs normally provide the necessary mechanical support and grounding. Using the correct standoff positions matters, but replacing the supplied screws with washers is not normally a repair for a no-POST problem. I would ask the shop exactly what was wrong and request a written explanation of the tests they performed.
Since the PC worked before it was put into sleep mode, a sudden CPU failure is not the only possibility. Reseat the CPU and RAM, inspect the socket for bent pins, clear the CMOS, check both motherboard power connectors, and try a minimal setup outside the case if possible. Also verify whether the board has any status lights or speaker-code support, since not every model includes visible diagnostic LEDs.
The shop's test result is useful if they really tested your CPU in two compatible boards and used a known-good CPU in yours, but the unusual comments about screws and a USB connector make a second opinion worthwhile. Do not assume the CPU is dead solely because of a verbal diagnosis. Document the condition of the system, ask for the diagnostic notes, and avoid letting anyone discard the original screws or other parts until the warranty situation is settled.
The motherboard is still under warranty, so I may test with a locally purchased CPU first and then pursue a motherboard replacement if the system still does not work.