Yes after few seconds there is beep and red light. In first place in my opinion, there wasn't problem in fan. Beacuse I recall, before changinfg fan it was same situation, like now. No hash. S5 was running for 6 months.
What the black button inside S5, near the fan connection ?
Do me a favor...
Unplug the 2 white ribbon cables that connect the hashing boards to the controller and plug them into the other two vacant slots and try the reset again [Make sure rig is off when swapping slots]. OR Have you tried that already?
I've unplugged mine before on an S3 and plugged them right back into the same slots and it started working again. I've never had a problem with it since. Your ribbon cables may not be long enough to plug into the vacant slots. Sometimes, they make them too short.