It would be helpful to try towards uncovering a solution if we knew what happened to these cards that effectively bricked them. From how it has been presented it seems like one morning you woke up and 3 of your cards suddenly wouldn't work. What preceded the bricking? Bridging pins through power cycles seems like a very unfortunate way to try and get your cards to work; at best this seems like a temporary solution. You are running windows, is that correct? I gathered that from the way you worded OP.

When I run into problems like this, or almost any miner I know that runs into problems like this they simply send their cards for an RMA or something along those lines. Is there any reason this is not a consideration currently? Some hobbyists or stubborn engineers always have their reasons.