The Newall DP90021100 is a two‑axis digital readout (DRO) module used on milling and lathe machines, featuring an LCD display and dual encoder inputs for X/Y axes. Common failure modes include loss of signal from one or both encoders, flickering or blanking of the LCD due to power supply instability, and intermittent communication errors between the DRO and the machine controller. First‑check diagnostics should verify that the 12 V/24 V power rails are within spec, inspect the encoder cables for continuity and proper shielding, and review any error codes displayed on the unit or logged by the host controller. If issues persist, examine the PCB for burnt components or loose solder joints, especially around the microcontroller and voltage regulators.[oss-gpt-20b]