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Title: Avalon 851 sockets melting Post by: Miraii on October 26, 2021, 11:34:41 AM Hi
I've had an issue a couple of times where my Avalon 851 devices atx sockets and 12 volt power cables melt and I had to resolder new sockets. I want to know why this happens and how to prevent it. it didn't happen to one device twice it was different devices each time and after soldering new sockets everything was back to normal. Title: Re: Avalon 851 sockets melting Post by: NotFuzzyWarm on October 26, 2021, 12:42:22 PM It happens from 2 things:
Too many plug/unplug cycles, even the best available pins for PCIe plugs are only rated for 25 cycles. El-Cheapo's as few as 5 cycles and whatever plating was on the pins is gone. Once the plating is damaged things go down hill very quickly. If the miner or PSU are used, who knows how many times the plugs have been cycled... Using aluminum or too thin wire for the PCIe cables. The wire itself is part of what removes heat from the connectors. If it's only 18ga then the pins WILL become warm, the plating will begin to oxidize and eventually fail. Title: Re: Avalon 851 sockets melting Post by: Miraii on October 28, 2021, 09:56:00 PM It happens from 2 things: Too many plug/unplug cycles, even the best available pins for PCIe plugs are only rated for 25 cycles. El-Cheapo's as few as 5 cycles and whatever plating was on the pins is gone. Once the plating is damaged things go down hill very quickly. If the miner or PSU are used, who knows how many times the plugs have been cycled... Using aluminum or too thin wire for the PCIe cables. The wire itself is part of what removes heat from the connectors. If it's only 18ga then the pins WILL become warm, the plating will begin to oxidize and eventually fail. Thank you for the concise explanation. So new pins and better wires should prevent this from happening. I thought maybe it's a hardware glitch or done type of malfunction from power supply or pmu. Title: Re: Avalon 851 sockets melting Post by: NotFuzzyWarm on October 28, 2021, 10:25:39 PM Ja. look for pins that are either silver plated (good for higher current, up to 5A per-pin and are 'slippery' usually good for the 25-cycles rating) or gold-flashed (almost as good but rated for fewer plug/unplug cycles) and 16ga copper wires.
Also a good reminder for folks out there: If you are using 2 PSU's to give the required power (the 851 is something like 1.8kw) each PSU can only feed 1 side of the miner! All the PCIe sockets on each side are tied together and if different PSU's are plugged into the same side they will literally fight each other to be the one doing the voltage regulation/supplying the most power and the result is not pretty... |