Choosing the Right Solder and Flux for Miner Repairs

Hey everyone. I just did some repairs on my miner and while I think I soldered those elbow power connectors right, I'm running into issues. I’m starting to wonder if I'm using the wrong materials. I watched some videos online and one of them mentioned that using "gold solder" is super important. But when I looked it up, all I found was jeweler's solder. Is that even what I need for these repairs? Here's the solder and flux I tried...

I gotta ask, do "bad" fluxes really exist? Aren't they all pretty much the same? I’ve been using this flux: https://www.zeusbtc.com/ASIC-Miner-Repair/Parts-Tools-Details.asp?ID=272 And this solder: https://www.zeusbtc.com/ASIC-Miner-Repair/Parts-Tools-Details.asp?ID=86 Not sure if they’re the best, but they work fine for what I need. After I solder, I always clean everything up, that’s how I learned it. What problems are you experiencing with your soldering? Is it that your hashboards aren’t being recognized?

Afternoon guys. I decided to try that flux you mentioned. For my S9, I yanked out the old solder because it looked kinda oxidized and put on new stuff, and now it’s hashing like a champ. To respond to the guy asking about hashboard recognition: mine works now, but I have this lovecore Chinese replica where I swapped out the connectors, and it’s not detecting the hashboards. Can anybody weigh in on that? It’s strange, no burning signs at all! Really appreciate all the help here.