How to Calibrate, Verify, Clean & Troubleshoot the A&D SJ-20KHS
- pete8781
- Jul 31
- 3 min read
Need more details or help choosing the correct item? Call MNM Scales at (832) 290-3120 or email mnmscales@yahoo.com.
A&D SJ-20KHS calibration is external, but correct calibration is only one part of reliable 20 kg × 10 g weighing. Level installation, a stable surface, correct pan seating, adequate batteries, a container that does not touch surrounding surfaces and routine known-weight verification are equally important.
For capacity, features and model-selection details, return to the SJ-20KHS buyer guide. See the SJ-20KHS application guide for food, produce, packaging and receiving workflows.
Set up the scale before calibration
Place the unit on a rigid bench away from vibration, fans and direct heat. Confirm that all feet contact the surface and that the pan is installed correctly. Let the scale and reference weight acclimate to the room. Remove every load, press zero and wait for a stable indication. Calibration performed on a rocking table or with a container touching the housing cannot produce dependable results.
External calibration workflow
Follow the A&D calibration procedure using an appropriate calibrated reference mass. Center the mass carefully and avoid shock loading. After the calibration routine finishes, remove the weight and confirm zero. Then apply an independent known reference representative of normal use. For documented quality systems, record the as-found result before adjustment and the as-left result after calibration.
Routine verification is different from calibration
Verification checks whether the scale is performing acceptably without changing it. Test zero, repeatability with the same reference several times and at least one working-range load. Move a reference to representative pan positions if production containers are not always centered. If results fail, investigate the installation before recalibrating. Repeated calibration can hide symptoms without correcting vibration, mechanical contact or damage.
Large-container and pan-contact errors
SJ-20KHS has a compact 230 × 190 mm pan despite its 20 kg capacity. A wide box or bowl can touch the display housing, bench or another object. Any contact supports part of the load outside the sensor and normally makes the reading low. Use a smaller container, a proper load-spreading accessory approved for the application or a larger platform scale. Never balance an unstable container on a small pan merely to reach the rated capacity.
Cleaning and reassembly
Remove the SUS304 pan and clean it separately. Wipe the housing with a lightly damp compatible cloth. Do not immerse or pressure-wash an SJ-HS scale. Dry the pan and support area completely, reinstall the pan without binding and verify zero plus a known weight. Residue beneath the pan can cause poor zero return or position-dependent readings.
Battery and power troubleshooting
Replace all four D batteries as a matched set, observe polarity and clean contaminated contacts according to safe service procedures. Low voltage can cause shutdown or unreliable operation. If the scale works on the AC adapter but not batteries, inspect battery orientation and contacts. Use only the specified adapter; an incorrect supply can damage electronics or introduce instability.
Common symptoms and likely causes
A drifting display often points to vibration, airflow, temperature change, moving product or mechanical contact. Failure to return to zero may indicate residue, pan binding or a load left on the scale. A consistent span error against known references may require calibration or service. A reading that changes with load position calls for inspection of leveling, pan support and eccentric loading. An overload indication means remove the load immediately; tare does not increase physical capacity.
Frequently asked questions
Is SJ-20KHS calibration internal? No, external. Should I calibrate every time the last digit moves? No—first control environment and verify with a known weight. Can I wash the whole scale? No SJ-HS washdown rating is listed. What causes a low reading with a large box? The box may be bridging against another surface. Should batteries be changed individually? Replace the complete set together. Does tare protect against overload? No. What should be checked after moving the scale? Level/stability, zero and a known reference load.
Comments