R9 290
Recommend Any graphic card repairer in lahore
No display and you want to get GPU repaired, I assume this means that your system is posting; no motherboard beeps or error codes on the motherboard itself etc.
Change all the other variables to determine if it's really the GPU that requires repair. Put the GPU in a different good system and check. Try a different PSU, HDMI cable, DisplayPort cable, monitor/TV etc.
Check the PCB of the GPU to check for any burn signs on any components. If there are then you might need a donor board for replacement parts. All this DIY hassle because there are no repair shops at such level, and the ones that agree to repair will try to learn on your stuff and make it even worse. Google/YouTube yourself and DIY.