A&D EJ-123 Manual, Explained: Setup, Keys, Counting, Calibration and Settings

By MNM Scales · Last updated October 31, 2026

The A&D EJ-123 is a milligram model in A&D’s Newton EJ series: 120 g by 0.001 g on a 110 mm round pan inside a breeze break, running on AC or batteries. Its manual is short but packed with display codes. This guide walks through it in plain language, with the codes as they appear on the balance, and adds what our technicians see on the bench. If you own the larger EJ-6100, it uses a different manual; see our EJ-6100 manual guide.

EJ-123 manual at a glance: specifications

Item	EJ-123
Capacity x readability	120 g x 0.001 g (display resolution 1/120,000)
Repeatability (standard deviation)	0.003 g
Linearity	±0.003 g
Sensitivity drift	±20 ppm/°C (10 to 30 °C)
Calibration weight (factory setting)	100 g (not included); the value can be changed
Counting	Samples of 5, 10, 25, 50 or 100 pieces; up to 120,000 pieces; minimum unit weight 0.001 g
Percent mode	Minimum reference weight 0.1 g; displays to 0.01 percent
Other units (capacity x readability)	oz 4.2329 x 0.0001 · ozt 3.8581 x 0.0001 · ct 600 x 0.005 · dwt 77.162 x 0.001 · grain 1,851.88 x 0.02
Display	7-segment LCD with backlight, 16 mm characters, updates 10 times per second
Power	AC adapter (included), or 4 AA batteries (not included) for about 80 hours on alkalines with the backlight off
Operating range	10 to 30 °C (50 to 86 °F), below 85 percent RH, non-condensing
Pan, size and weight	110 mm round pan; 190 x 211 x 131 mm; about 1,160 g
In the box	Balance, breeze break, AC adapter, instruction manual

Setting up the EJ-123

1. Fit the pan and breeze break as shown in the manual. The breeze break keeps air currents off the pan, which matters at 0.001 g.
2. Choose the spot. A firm bench away from dust, drafts, vibration, large temperature swings, condensation, magnetic fields, direct sun, heaters and air conditioners.
3. Level it. Turn the leveling feet until the bubble in the spirit level sits in the center of the circle.
4. Power it. Plug the AC adapter into the jack on the back, or fit 4 AA (LR6) batteries, watching the polarity. Replace all four when lb0 shows, and use one type of battery. A spare TB-662 AC adapter is sold separately.
5. Warm it up. A&D asks for the power to be on for at least half an hour before use.
6. Calibrate when you first set it up and every time you move it (see below).

At power-on the EJ-123 zeroes itself if the load is within ±50 percent of capacity; above that it tares the load and lights NET and ZERO. To have it turn itself off at zero, set poff 1 in the function table. A security slot on the back takes a security cable for shared benches.

Setup tips from our technicians

Our TDA-registered technicians calibrate milligram balances like the EJ-123 in our shop. These are the setup habits they recommend.

• Give it the full half-hour warm-up before calibrating. A balance calibrated cold can read differently an hour later, once it has warmed up.
• Keep the breeze break fitted and closed while reading the last digit. A ceiling vent or a person walking past is enough to move a milligram.
• Use the AC adapter for long sessions and keep fresh batteries for field work; the backlight setting ltUp is the biggest battery saver.
• Calibrate where the balance will be used, after it has settled to the room, rather than at a desk before carrying it to the bench.

The keys and the CAL switch

Key	In weighing	In settings
ON:OFF	Turns the balance on or off	Cancels and turns the balance off
RE-ZERO	Zero and tare in one key: zeroes within ±2 percent of capacity, tares a container above that	Changes the blinking digit or the parameter
UNITS	Steps through the stored units, pcs and percent	Cancels and moves on, or returns to weighing
SAMPLE	In pcs or percent, enters sample or reference storing; adds to the total in accumulation; hold it to open the function table (func)	Selects the item or digit
PRINT	Sends the reading to a printer or PC; hold it to start or end a GLP title block	Stores the setting (Enter)
CAL switch (under the cover on the bottom)	Hold until Cal shows to calibrate; keep holding to CC for a calibration test	–

Press the keys with a finger, never a pencil or other sharp object; A&D warns against it.

Units: store only the ones you use

The EJ-123 can show grams, ounces, troy ounces, carats, pennyweight, grains, newtons, pieces and percent, plus density (specific gravity) with the EJ-13 density kit (not included). Pounds are not among its units. Which ones appear was set at the factory; you choose from those.

1. Hold SAMPLE until func appears, then press SAMPLE until Unit appears and press PRINT.
2. Press SAMPLE to show each unit, and RE-ZERO to select it (the STABLE indicator marks a selected unit).
3. Press PRINT to store the set, then UNITS to go back to weighing. The first unit you selected becomes the one shown at power-on.

Grains for reloaders

In grains the EJ-123 reads up to 1,851.88 gr in steps of 0.02 gr, using the UK grain of 0.06479891 g. Store grains with the steps above so the unit is one press of UNITS away, and keep the breeze break closed for the last digit. For a side-by-side of reloading balances, see our reloading scale comparison; our grain to gram converter handles the math.

Counting, percent, hold and accumulation

Counting (pcs)

1. Press UNITS until pcs shows, then press SAMPLE.
2. Press SAMPLE again to pick 5, 10, 25, 50 or 100 samples.
3. Tare a container with RE-ZERO, put the chosen number of pieces on the pan and press PRINT to store the unit weight.
4. Add the parts to count. With ACAI on, adding a few more pieces (more than three) makes the ACAI indicator blink while the balance refines the unit weight; leave the pan alone until it stops.

If the pieces are too light, the balance asks for a bigger sample (10 -, 25 -, 50 -, 100 -) or shows lo. Place the number shown and press PRINT. With the factory Umin 0 setting the minimum unit weight is 0.001 g. See our counting scale buying guide for larger batches.

Percent

Press UNITS until the percent unit shows, press SAMPLE, then RE-ZERO, place the reference (at least 0.1 g) and press PRINT. Each sample then reads as a percentage of that reference, down to 0.01 percent.

Display hold

Set Hold 1 to Hold 4 in the function table to freeze a stable reading once the load is more than 4 digits from zero. The hold releases when the reading moves more than the limit you chose: 10, 50, 100 or 200 digits. Hold 0 turns it off.

Accumulation (total)

Set totl 1 and the M+ indicator appears. Press SAMPLE on a stable reading to add it to the total; press UNITS to see the count and the total, and RE-ZERO while they show to clear them. The count stays under 1,000 and the total is kept when the power is off.

Function table settings

Hold SAMPLE until func shows, press PRINT, then SAMPLE moves to the next item, RE-ZERO changes the value and PRINT stores it. UNITS returns to weighing. Factory settings are marked with an asterisk.

Item	Settings	What it does
poff Auto power-off	0* off · 1 on	Turns off on its own at zero
Cond Response	0 fast · 1* · 2 slow	Higher is steadier on a busy bench
st-b Stability band	0 = 0.5d · 1* = 1d · 2 = 2d	When the STABLE indicator lights
trc Zero tracking	0 off · 1* on	Holds zero against slow drift
pnt Decimal point	0* point · 1 comma	Separator on display and output
prt Data output mode	0 stream · 1* PRINT key · 2 auto-print A · 3 auto-print B · 4 command only	When data goes out the interface
pUse Output pause	0* none · 1 = 1.6 s	Spacing for continuous output
info GLP output	0* none · 1 AD-8121 printer · 2 general (PC)	Adds calibration and test reports
bps Baud rate	0 = 2400* · 1 = 4800 · 2 = 9600 · 3 = 1200	Must match the printer or PC
btpr Data bits and parity	0* 7 bits even · 1 7 bits odd · 2 8 bits none	Must match the printer or PC
aCai ACAI	0 off · 1* on	Refines the unit weight while counting
Umin Minimum unit weight	0* = 1d · 1 = 1/10 d · 2 = sample total of 5d or more	Smallest piece the counter accepts
smpl First sample number	0* 10 · 1 = 25 · 2 = 50 · 3 = 100 · 4 = 5	Starting sample size in pcs mode
ldin Liquid density input	0* water temperature · 1 density	Used with the EJ-13 density kit
Hold Display hold	0* off · 1 to 4 = 10, 50, 100 or 200 d	See display hold above
totl Accumulation	0* off · 1 on	See accumulation above
ltUp Backlight	0 off · 1 to 4 off after 5, 10, 30* or 60 s · 5 always on	Battery life versus visibility

EJ-123 calibration with a 100 g weight

The EJ-123 calibrates with an external weight. Its stored calibration value is 100 g, and A&D asks for a weight of more than two thirds of capacity, so change the value only if you calibrate with a different weight above 80 g. The A&D 100 g calibration weight (not included) matches the factory value; see calibration weight classes and all calibration weights.

1. Warm the balance up for at least half an hour with nothing on the pan.
2. Press and hold the CAL switch under the cover on the bottom until Cal appears, then release. The display shows Cal 0.
3. To change the weight value, press SAMPLE, set the digits (SAMPLE moves, RE-ZERO changes) and press PRINT. The new value is kept after power-off.
4. With Cal 0 showing and the pan empty, press PRINT to weigh zero. Do not touch the pan.
5. When the weight value shows, place that weight on the pan and press PRINT.
6. end appears. With GLP output on, glp shows while the calibration report goes out. Remove the weight; the balance then turns off.

If you move the balance and have no weight on hand, A&D’s gravity acceleration correction (RE-ZERO at Cal 0) sets the local gravity value from the map at the back of the manual. A calibration with a weight on site makes it unnecessary.

To check accuracy without changing the calibration, hold SAMPLE and PRINT together until CC shows (or keep holding the CAL switch past Cal), weigh zero, then the test weight. This works even after the CAL switch is sealed, and with info 1 or info 2 set the balance outputs a calibration test report.

-Cal e means calibration stopped because the weight was too light for the stored value; check the pan and the weight value. If the reading drifts after calibration, see scale will not zero or keeps drifting.

Common mistakes we see

• Calibrating straight after power-on, before the half-hour warm-up.
• Using a weight well below the stored value, which ends in -Cal e; match the weight to the value on the display.
• Touching the pan or the breeze break while zero is being weighed.
• Handling the calibration weight with bare fingers; use gloves or tweezers so skin oils stay off it.

EJ-02 USB and EJ-03 RS-232C interfaces

The EJ-123 has one option slot, so it takes either the USB or the RS-232C interface, not both.

• EJ-02 USB (not included): sends the weight value one way into Excel, Word or Notepad on a PC with no driver. It cannot receive commands.
• EJ-03 RS-232C (not included; EJ-03C comes with a cable): connects a printer or PC through a straight 9-pin D-Sub cable. The balance is DCE: pin 2 transmit, pin 3 receive, pin 5 ground, 6 DSR, 7 RTS, 8 CTS.

Over RS-232C the balance answers three commands: Q sends the current reading, Z zeroes or tares, and U changes the unit. Data lines start with ST (stable), QT (stable count), US (unstable) or OL (over range), followed by the value and unit, and end in CR LF. Set prt, bps and btpr to match the other end. For cabling and software, see how to connect a scale to a computer.

For GLP records, set an ID number under id in the function table; the calibration and test reports then carry the maker, model, serial number and ID. Holding PRINT until 5tart shows starts a title block, and holding it until recend shows closes it.

Density with the EJ-13 kit

The EJ-13 density determination kit (not included) swaps the pan and breeze break for an upper pan to weigh in air and a lower pan to weigh in water. Select SG with UNITS, weigh the sample in air and press SAMPLE, then weigh it in water and press SAMPLE again; the EJ-123 shows the density to three decimals. The factory liquid setting is water at 25 °C; hold UNITS in SG mode to enter a different water temperature or, with ldin 1, the liquid density directly.

EJ-123 error codes

Display	Meaning	What to do
eeeeee	Overload	Remove the load; it is above 120 g
--e	Range over notice: strong upward force on the sensor	Check for anything caught around the pan; if it stays, the sensor may need service
lo	Sample too light for a unit weight or percent reference	Use more pieces or a heavier reference
10 - to 100 -	Sample quantity notice	Add the number of pieces shown and press PRINT
-Cal e	Calibration weight too light	Check the pan and the calibration value
lb0 / Hb0	Batteries exhausted / battery voltage too high	Fit four new batteries or use the adapter
Hb1 / lb1	Adapter voltage too high / too low	Check that the adapter is the correct type
error1	Reading will not settle	Stop vibration and drafts, then press UNITS
error plus another number	Internal error	Empty the pan, turn the power off and on; if it stays, request service

If an error will not clear, our repair bench can help; codes for other brands are in our scale error codes guide.

Who uses the EJ-123

The EJ-123 fits schools and teaching labs, quality and research labs, jewelers and gem dealers, reloaders and hobbyists, and small manufacturers weighing samples, additives and small parts. The common thread is milligram readings on a compact balance that also runs on batteries.

Selling by weight

The EJ-123 is not NTEP. It is built for lab, school, testing and general weighing, and its grams, carats, pennyweights and troy ounces suit testing and inventory. For buying or selling precious metals by weight, choose a Class II model such as the A&D FX-120iN or the A&D FX-200iN. Our legal for trade jewelry scale guide explains the Class II options.

Texas note: TDA does not require an NTEP certificate for every device, but the scale must meet NIST Handbook 44 and suit its use; some scales do need one, so we recommend NTEP models and can check yours. See TDA’s scales used in trade guidance (PDF) and our TDA scale certification guide, or call us or TDA to confirm your use.

Not sure your use counts as trade? Try our free legal-for-trade scale checker.

Care and storage

Do not take the balance apart. Clean it with a lint-free cloth dampened with warm water and mild detergent; no organic solvents. The breeze break is anti-static: wipe it with a dry or water-dampened lint-free cloth, never alcohol. Ship it in the original packing. Other models in the series are the EJ-303 (310 g x 0.001 g), EJ-120 (120 g x 0.01 g) and EJ-200 (210 g x 0.01 g); see all A&D precision balances.

Calibration, repair and rentals

• Calibrated before it ships: in-house calibration $95 or NIST calibration certificate $395 for balances up to 2.2 kg, including the EJ-123. See NIST vs in-house certificates.
• Mail-in calibration: pack the balance in its original packing, as A&D recommends, and ship it to our shop with the mail-in calibration service.
• Cypress pickup by appointment: drop off or pick up at our Cypress, TX shop (21249 FM 529 Rd, Cypress, TX 77433).
• On-site service: on-site calibration is $295 plus $2 per mile per visit, plus the calibration fee for each scale. See balance calibration in Houston.
• Repair: sensor, adapter, keypad and interface problems go to our scale repair bench.
• Rentals: we rent all types of scales; ask about a scale rental while yours is in for service.

Frequently asked questions

Where can I find the A&D EJ-123 manual?

A&D publishes the EJ-123 instruction manual (1WMPD4002746) as a PDF and lists the EJ series on its Newton EJ series page.

How do I calibrate the A&D EJ-123?

Warm it up for half an hour, hold the CAL switch under the bottom cover until Cal shows, press PRINT to weigh zero with the pan empty, place the 100 g weight (or the value you set) and press PRINT. When end shows, remove the weight.

What calibration weight does the EJ-123 use?

The factory value is 100 g. A&D asks for a weight of more than two thirds of capacity. The weight is not included.

Where is the CAL switch on the EJ-123?

Under a cover on the bottom of the balance. Hold it to start calibration (Cal) or keep holding for a calibration test (CC).

Can the EJ-123 weigh in grains?

Yes. It reads up to 1,851.88 grains in steps of 0.02 grain once grains are stored as a unit.

Can the EJ-123 connect to a computer?

Yes, with one interface in its option slot: the EJ-02 USB sends readings straight into Excel or Notepad, and the EJ-03 RS-232C connects a printer or PC and accepts the Q, Z and U commands. Interfaces are not included.

How long do the batteries last in the EJ-123?

About 80 hours on 4 AA alkaline batteries with the backlight off. Batteries are not included; the balance also runs on its AC adapter.

Is the EJ-123 legal for trade?

The EJ-123 is not NTEP. For buying or selling precious metals by weight, choose a Class II model such as the A&D FX-120iN or FX-200iN.