While making repairs or adjustments to RADAR units:

Discharging all high-voltage capacitors to ground is crucial for safety when making repairs or adjustments to RADAR units. These units can contain capacitors that store significant electrical energy, which, if released unexpectedly, might cause severe shock or even fatal injuries. By discharging these capacitors before working on the unit, you eliminate the risk of electrical hazards, ensuring a safer working environment.

When dealing with RADAR equipment, it is important to recognize that these systems can operate under high voltages and currents. Therefore, following proper procedures for equipment handling—such as discharging all high-voltage capacitors—is vital to prevent accidental electric shock. This practice is indicative of good safety protocols in the field of electronics repair, particularly in high-voltage systems like RADAR.

The other options, while they may pertain to safety or operational procedures in specific contexts, do not address the immediate risk of working on energized components as effectively as discharging high-voltage capacitors does. For instance, wearing fire-retardant clothing is a good safety practice, but it doesn't mitigate the specific risk posed by high-voltage capacitors. Similarly, maintaining the filament voltage or reducing the magnetron voltage relates more to operational efficiency than to immediate safety during repairs. Thus,