Single-layer PCB Diagnosis & Repair

I have several double-layer printed circuit board that has stopped performing reliably. Several symptoms point to multiple underlying faults: a few components no longer behave as expected, some traces appear open or damaged, and certain connectors intermittently lose continuity... (Budget: ₹1500 - ₹12500 INR, Jobs: CAD/CAM, Circuit Board Layout, Circuit Design, Electrical Engineering, Electronics, Embedded Systems, PCB Layout, Prototyping, Reverse Engineering, Troubleshooting)