LimeSDR Mini - Power Supply Fault and Succesful Repair

I have a LimeSDR Mini V1.3 that recently failed after about a year of daily use. The symptoms were that it drew about 800 mA from the USB 5v supply, got hot in the power supply area of the board and finally ceased working when it properly overheated.

I traced the problem to a faulty switching regulator, IC12, the LMZ10501 that supplies 3.3 v to the board. Although functioning, it was also drawing nearly half an amp from the supply itself. I removed it from the board (careful use of scalpel and hot soldering iron) and fitted an external linear 3.3 v regulator to the edge connector terminals. The Lime is now working again.

Next job is to mount the board and regulator in a decent box with a fan. It was in one of the ESA cases and always ran hot - I suspect this may have accelerated its failure.

PCB after surgery shown below. The arrow shows where IC12 was. It’s always worth trying a repair!

Dave, G8GKQ