Like many of you I’ve had the displeasure of my L3+ lose a hash board, frustrating, but sometimes easily fixable.
Often times, and I mean often, you’ll find that the 14.2V boost circuit has died which leads to your hash rate dropping to nothing for that board. I’ve seen many fixes (and attempts at fixes) and talked with a lot of folks about this. Some of the crazier things I’ve seen is removing C943 (still don’t know why they removed it) and running a jumper wire all the way across the board to D1. That gets you ~12V at the boost circuit (they did remove D1 to isolate from the old circuit) however that’s not enough to get the board to work to its full potential and it’s not a clean 12V so you can cause damage to your hash board down the line if you have power spikes.
NOTE – Per the manufacturer – Before applying power for the first time, turn the output voltage adjustment screw 20 full turns counter clockwise (CCW). Several people have reported the buck converter frying on the external module and this should insure it won’t burn out on power-on. Additionally insure you adjust the voltage using a multimeter before attaching the output to your hash board.
I can type all day long, but figure it’s better to just put it in a video. For reference I used a step-up boost converters I found on Amazon for about $1 a piece.