i only intend to run 3 R9-270 cards for while on this new rig.. (was my plan until i broke my mobo) currently i have a 1000 watt PSU
but when im ready for more cards i will add a second 1000 watt PSU

yep tried every card i have, in that 16x slot... no luck.

looking at getting ASROCK h81 pro btc new CPU and new RAM.
more than i wanted to spend, but not about to give up
trying to build this 3 card R9 270 rig as been a (lets call it a learning experience)
and so far i have really "enjoyed" most of it..
at least this way the rig will be something i can grow into rather than grow out of.
Thanks for your help!

yep all my cards work fine over the 1x slot with the USB riser.

this Motherboard is like 7 or 8 years old. EVGA 113-M2-E113

i tried unplugging the machine and pulling the battery off the mobo and letting it sit for about 10 minutes, hoping that just a simple reset would do the trick, but i still get nothing out of the card in the 16x slot.
i was under the impression you could run a 1x riser in a 16x slot with out issue.

i tried to run a 16x - 1x powered riser (USB style) in the 16x slot
nothing happened so i swapped out the riser and just put the card back in.
now any card i use wont work in the 16x slot. no fans, no video output.
any idea? i think its toast..

new USB risers came in today, problem SOLVED!
Thank you for your help kalus!

OHHH OK.. i tried a card that is known to work in the x1 slot with the riser but the it didn't show up in the device manager.

^ thats is exactly the same riser that i am using thanks for the link!

i found an old analog PCI modem should i try it in the PCI ports to see if the ports work?
this computer was used before it got it.

so swapped out the "non working card" and it works just fine when its in the PCI-E slot.
noticed 2 of my risers are shot. fired the printed circuit on the 1x end... i have one good riser left and ran tests with that..
tried putting the riser into and open 16x slot, tried every PCI slot i have but not the PCI-E slot. that did not register the card.

the motherboard is EVGA 113-M2-E113
8 gigs of ram
AMD athlon 64 x2 duel core 3200 Mhz

i will need new risers, i want quality. any recommendations? 

Kalus, you have been very helpful thank you.

i don't think its showing up in device manager. what would it show up as?
using windows 7

ok i see the card thats in the mobo it lists a r9-200 series

i also see something listed as Co-processor under the "other devices" tab
and it says the drivers are not installed for it
so i ran the auto scan and it returned no results  

so i have 3 R9 270 cards
one is in the PCI-E slot on the Mobo
try to get another one to connect but it does not appear to be showing up im using cgminer
and have one card (on the mobo) working and mining.
trying to get another card working using a 16x - 1x powered riser i have that connected to the 1x slot on the mobo
i tryed it with out the jumper wire in the socket and got nothing. tried it again with the jumper wire and still nothing
i can get CGminer to fire up with a 2 card config file but it still shows just the one card.
once i get the second card working i will add the third.
any input is greatly appreciated, Thank you.