The PSU on my mom's computer failed, so I replaced it, plus I swapped out the K8N Neo2 motherboard with one that I found on eBay from China that claimed to be "100% Tested and Working." With the PSU and motherboard replaced, it would beep during POST with a memory failure error. After experimenting with DIMM slot positions, it turns out that the computer boots fine with the RAM sticks in DIMM1 and DIMM3, but not in 2 or 4. It doesn't matter which stick I use so the actual RAM is fine. The processor is AMD Athlon 3500+.
Someone told me that this indicates one of the memory channels is not working so probably the memory controller on the CPU is fried: "When 2 slots on the same channel fail it's probably the CPU-socket or CPU-itself."
But then I read messages on forums, when others ran into a similar problem, that conclude most likely it's the motherboard.
Is it typical for a motherboard component failure, such as with the capacitors, to affect just one of the memory channels?
If the memory controller on the Athlon 3500+ CPU failed, wouldn't the CPU stop working completely, or would it limp along fine with the other memory channel?
I'm reading that the memory controller on the Athlon 3500+ is on-die, on the CPU.
On another forum someone writes: "I had an AM2 CPU which only worked with single channel memory, I expect this was a memory controller issue... Tried it with different Motherboard & Memory but it was always the same issue."
How likely is that, I could have the same issue?
(I didn't try memtest because it won't POST only if I use slots 1 or 3, so the RAM sticks are probably fine)
After the PSU failed, I attempted to test the failed motherboard with another PSU. There were times when some parts would power on, except the CPU fan would not spin (some, but not all of the power circuits failed on the old motherboard). So I wonder if the Athlon 3500+ CPU fried its memory channel portion during this testing, when it was receiving power without the CPU fan spinning.
The PSU or motherboard could have caused some damage to the CPU but I wouldn't trust some random motherboard from ebay. Just test it with a known good and working motherboard first and if it doesn't work, then the CPU is partially broken.