Palit GTX 980TI working via a riser but not in x16 slot

[mmx01]

Hi,

Interesting case, I have a gtx 980ti which suffered typical drmos failure. I replaced it together with 12V PEX switching transistors, all blown fuses etc. No shorts on vcore, vmem, pex or any other rails.

Yet the card does not give any sign of life when plugged into pcie x16 slot unless I plug it in via a mining riser?! I was troubleshooting it using riser as it is easier to measure etc. It worked so I assembled the card put in the computer and no post. When I move it to the riser it works again.

Checked all voltages on PCIE finger 12V, 3V3 while plugged in, PEX_RST goes to 3.2V but it won't post without a riser.

I concentrated around voltage rails since that's what riser does independently of pcie slot via dedicated vregs off sata power connector but I don't seem to find any low resistances or shorts alltogether. In both configurations all voltages are present and PEX_RST goes high.

I have even taped/covered the x16 connector on the card after A/B18 leaving just 1x lanes connecting but still no post without a riser.

Any clues? Thanks.
M.

[ktmmotocross]

Re: Palit GTX 980TI working via a riser but not in x16 slot

check every pcie lanes for short or unusual resistance. some pcie lane not work

[mmx01]

Re: Palit GTX 980TI working via a riser but not in x16 slot

I have physically covered all contacts after PCIE x1 lanes before inserting into the x16 slot (black electric tape over pcie finger on both sides) but will measure all pairs to be sure.