Is there any way of testing a PCB by using only one end?

Question

For a normal PCB we can do continuity test by putting multi meter probes across 2 ends, but in my case only one end can be used.

The pcb is covered fully and only one wire connected from pcb is available.

Any way of testing it by making use of only that one wire

Answer 1

If there is limited access to a single wire connected to the PCB and need to test for continuity, there are a few methods to consider:

(1) If the PCB has a ground plane or a known common reference point, use it to test for continuity. Connect one probe of the multimeter to the wire you have access to and the other probe to the ground plane. If the circuit is continuous, see a reading indicating low resistance (close to zero ohms).

(2) If there is access to any other known points on the PCB, connect one probe of the multimeter to the wire and the other probe to the known point. This known point could be a test point, a connector pin, or any other accessible component lead. Again, if the circuit is continuous, see a low resistance reading.

(3) If there is a schematic diagram of the PCB, attempt to trace the circuit from the known wire to find other points that is accessible. This might involve using the schematic to identify components and their connections.

(4) If there is a dedicated continuity tester, it can be easier to use in situations where there is limited access. A continuity tester emits an audible tone when a continuous connection is detected, making it useful when visibility is restricted.

(5) A micro ohmmeter is a more sensitive device that can detect very low resistances. If there is access to one, it can be useful for testing continuity through very small paths.

(6) In some cases, the wire being accessed might not actually be a power or signal connection; it could be a ground or other reference point. Exercise caution and ensure you're not applying voltage or current inappropriately to sensitive components.