| Exterior and enclosure | Inspect the case, handles, feet, seams, screws, and any signs of impact, liquid exposure, or unauthorized opening. | Minor cosmetic wear with an intact enclosure and no evidence of liquid ingress or loose parts. | Cracks, bent panels, corrosion, missing screws, or damaged seals may indicate drops, moisture, or repairs. | Ask about the instrument’s service history and request a close inspection of any damaged areas. |
| RF test ports and connectors | Check connector threads, center contacts, port alignment, and protective caps. Avoid touching connector contacts. | Threads are clean and undamaged; contacts appear centered and free of visible dents, debris, or corrosion. | Cross-threading, a loose connector, a visibly bent contact, or signs of repeated side loading can affect measurements. | Request inspection by a qualified technician if a port looks damaged. Include connector repair or verification costs in the purchase decision. |
| Power-on and basic operation | Start the analyzer and observe its startup checks, display, controls, menus, and ability to save or recall a measurement setup. | It starts without persistent error messages; controls respond; the display is readable; basic functions operate consistently. | Unexpected shutdowns, persistent errors, unresponsive keys, display defects, or unstable readings require investigation. | Test the unit in person where possible, and request a demonstration of the functions needed for your work. |
| Frequency range and measurement functions | Confirm the actual frequency range, number of ports, and measurement functions against the intended application and the unit’s configuration. | The documented configuration covers the required bands and measurements, such as reflection or transmission measurements, where applicable. | A base configuration may not include a required frequency option, measurement mode, or port capability. | Verify the configuration in the instrument’s menus and documentation; do not rely only on the exterior model label. |
| Calibration status and records | Review the calibration certificate or service record, including date, measured functions, stated uncertainty, and any limitations. | Records identify the instrument and show calibration or verification relevant to the measurements you need. | Missing, expired, incomplete, or mismatched records make measurement accuracy and traceability difficult to assess. | Ask whether the seller can provide current calibration through a qualified laboratory. Confirm that the calibration scope suits your use. |
| Calibration kit and measurement verification | Check whether a compatible calibration kit is included and whether its standards, connector type, and frequency range suit the analyzer. | The kit is complete, identified, and in good physical condition; verification can be performed with suitable known standards. | Missing standards, damaged connectors, or an incompatible kit can prevent a valid calibration at the test plane. | Confirm compatibility and the kit’s condition. If possible, compare a measurement against a known verification standard. |
| Battery and power supply | Check battery condition, charging behavior, power-supply output rating, cable condition, and connector fit. | The unit operates from its supplied power source; the battery charges and holds charge adequately for the intended use. | Swelling, leakage, excessive heat, intermittent power, or damaged cables are safety and reliability concerns. | Do not use a swollen or leaking battery. Confirm availability and cost of a suitable replacement before purchase. |
| Included accessories | Inventory the listed accessories, such as RF cables, adapters, test leads, calibration kit, power supply, battery, and protective case. | Accessories are present, undamaged, and suitable for the instrument’s connectors and frequency range. | Unlisted or damaged adapters and cables may introduce measurement errors or require replacement. | Get an itemized accessory list in writing and price any missing or unsuitable items separately. |
| Documentation and ownership | Request the user manual, configuration details, service history, and confirmation that the seller can transfer the instrument legally. | Documentation matches the instrument, and the seller can explain its source and included configuration. | Unclear ownership, inconsistent serial information, or missing configuration details can create avoidable risks. | Record the instrument identification and agreed configuration on the sales documentation. |