I have an old ABIT socket 939 AN8-ultra mobo installed in my system. I have many reasons to believe that DIMM slots 2, 3, and 4 are not functional.
1) Memtest errors when DIMM is in those slots, but none when running in DIMM 1.
2) Crashes when windows is loading if module is in slot 3.
3) Abit says to only run a single module in Slot 1 or Slot 3.
4) I tried running windows with a module in Slot 2, which works for some time, but eventually windows BSODs. No BSODs are ever displayed when module is in DIMM 1.
5) When running Dual channel with two verified working, identical modules in Slots 1 and 2, BSOD will result as above in 4.
What sort of physical findings could manifest on the motherboard? The slots themselves seem dust and corrosion free, and I've blown them out with compressed air. I've already looked for bad caps and haven't seen anything alarming. I've also read that soldering defects could be the culprit, but I'm not certain where the soldering would be located in relation to the DIMM slots. If it's relevant, where could I be looking to detect fractured soldering? A quick google search makes me think that I should be checking for this in these places. Is there anything else I should be inspecting?