All-O-Matic SW-300 Repair | Dallas

Is this a All-O-Matic SW-300?

The SW-300 is All-O-Matic’s standard pad-mounted swing operator: a box on a concrete pad inside the gate with a two-piece arm running to a bracket on the leaf. All-O-Matic’s own manual calls it the company’s most popular operator and describes it as continuous duty for residential and light commercial use. It is sold as the SW-300 AC (1/2 HP, 120 VAC) and the SW-300DC PRO (24-volt brushless with built-in batteries).

What sets it apart from its bigger sibling, the SW-350, is how it releases and how it protects itself. The SW-300 has a quick-release arm — a lever on the arm hub held closed with a bolt or padlock — and an external torque limiter adjusted with a large nut. The SW-350 uses a foot pedal and a clutch inside the gearbox. If there is a pedal on your unit, you have an SW-350.

Chassis label reading SW-300 AC or SW-300DC PRO
A quick-release lever on the arm hub, locked with a bolt or padlock
A large torque limiter nut at the output shaft
A flat primary arm joined to a round pipe arm by knuckles with set screws
No foot pedal on the operator
On the DC PRO, two 12-volt batteries inside the housing

Also labelled: SW-300 AC, SW-300AC, SW-300DC PRO, SW-300DC

SW-300 at a glance

Motor (SW-300 AC): 1/2 HP, 120 VAC
Motor (SW-300DC PRO): 24 VDC brushless, 1/2 HP
Max gate weight: 800 lbs (AC); 1,200 lbs (DC PRO)
Max gate length: 20 ft
Opening time: 17 seconds per 90° (AC); adjustable 17–25 seconds per 90° (DC PRO)
Gearbox: 60:1
Torque limiter: 40A54TX2 with torque limiter
Chain: 40NP
Arm: Quick-release arm, rectangular or round
Emergency release: Quick-release arm
Battery backup (DC PRO): Integrated, two 7Ah 12 VDC batteries; up to 250 cycles
Control board: ACPCB-UL (AC); BLDC-ULPCB (DC PRO)
Duty cycle: Continuous
Dimensions / weight (AC): 12" × 17" × 25.5"; 110 lbs plus 35 lb arm
UL 325: Listed by All-O-Matic as UL 325 2018 compliant

From All-O-Matic’s published documentation. Your unit’s label and manual take precedence.

What your SW-300 is doing, and what usually causes it

The motor runs but the arm slips and the gate hardly moves
Usually: A torque limiter nut that has backed off, a quick-release lever not fully closed and pinned, a loose arm adjusting screw, or a leaf so stiff on its hinges that it now exceeds the limiter setting.
What we do: We open the lever and swing the leaf by hand to feel the hinges, then re-lock the arm, set the limiter from the slip point and confirm it still slips when we hold the gate.
The gate doesn’t open as far as it used to
Usually: Loose set screws letting the pipe arm move in its knuckles, a limit cam that has shifted, or a limiter slipping a little every cycle near full open.
What we do: We mark the arm, check each knuckle’s set screws, reset the limit cam and look for where in the swing the slip happens.
It struggles or slips at the same spot every time
Usually: Arm geometry off the manufacturer’s layout, so the operator loses leverage near the end of travel, or a hinge binding at that angle.
What we do: We measure the primary arm against the closed and open bracket positions and correct the arm length or bracket position.
On windy days the gate stops or reverses
Usually: Wind load on a solid or privacy-panel leaf exceeding the limiter or tripping reversal.
What we do: We confirm the limiter and reversing are set correctly for the gate, and tell you honestly if the leaf area is more than a 20 ft, 800 lb-class operator should be handling.
On our double gate one leaf lags or the pair gets out of sync
Usually: Master/slave cable damage, different limit settings on the two operators, a slave unit with a slipping limiter, or accessories wired to the slave instead of the master.
What we do: We set each operator up on its own, verify the shielded link cable, and then re-link and test the pair.
After a board was replaced, the gate runs the wrong way
Usually: Opening direction not set for the install. In All-O-Matic’s swinger manual the limit and motor wire colors for left- and right-hand opening are reversed between the SW-300 and the SW-350, so a wiring chart for the wrong model gets it backwards.
What we do: We confirm the handing and set the wiring or direction setting to the SW-300 chart.
The DC PRO gives up during a power cut
Usually: Batteries that no longer deliver the up-to-250 cycles All-O-Matic quotes, often after a few hot summers.
What we do: We load-test the batteries and the charging circuit and replace what has failed.

How the SW-300 works — and what that means for repair

The torque limiter: set to slip, on purpose

The SW-300 transmits drive to the arm through a torque limiter on its output (All-O-Matic part 40A54TX2), fed by a #40 chain from a 60:1 gearbox. The limiter is shipped loose. The installer tightens its large nut with a 20-inch pipe wrench until the arm does not slip while the operator runs, then grabs the gate mid-cycle to confirm it still slips. All-O-Matic calls it an important adjustment to take time over.

So a limiter that slips during normal operation is telling you the gate needs more torque than when it was set — stiff hinges, a sagging leaf dragging, or wind on a solid gate — or that the nut has backed off. A limiter that will not slip when the gate is held has been overtightened, and every hard stop is going into the gearbox.

The quick-release arm and why it gets left open

For a power failure, the SW-300 is released by removing the bolt or padlock from the arm lever and opening it, which frees the gate to be pushed by hand. To put it back in service, the lever is closed, re-pinned, and the arm adjusting screw tightened with an Allen wrench as tight as it will go.

If the lever is closed but not re-pinned, or the adjusting screw is not snugged, the operator runs and the gate barely moves or drifts out of position. It is one of the most common SW-300 no-fault calls after an outage.

Arm geometry decides how hard the SW-300 works

All-O-Matic’s layout is precise. You mark the ground under the gate bracket with the gate closed and again with it open, draw a line through both marks, and put the operator’s center shaft on that line. The primary arm section is exactly half the distance between the two marks — the manual prints “PLEASE BE EXACT” — and a chart sets the pad position by gate length up to 22 ft.

An arm that is too long or too short makes the operator push at a poor angle near the ends of travel, which shows up as a limiter that slips at the same point every cycle. For gates 12 ft or less with only 20 to 34 inches behind the open leaf, All-O-Matic publishes a separate compact installation layout.

Limits and pairs of gates

In All-O-Matic’s swinger manual the gate travel is set with limit cams: power off, loosen a cam with an Allen wrench, rotate it, retighten and test. On dual gates, two SW-300s run as master and slave over a shielded two-wire cable, and the manual says to set limits and reversing on each operator as a standalone unit before linking them, with all accessories wired to the master.

The DC PRO adds a slow start and stop algorithm, adjustable speed of 17 to 25 seconds per 90° and a leaf delay — useful where overlapping leaves have to open in order.

SW-300 parts we repair, adjust or replace

A failed part is not a failed operator. These are the components that actually wear or fail on the SW-300, and what we do about each.

Torque limiter (40A54TX2) and adjusting nut
Adjusted
Drives the arm while allowing it to slip if the gate is held or jammed.
Signs it has failed: Slipping in normal use, or no slip at all when the leaf is held mid-cycle.
Quick-release arm hub, lever and adjusting screw
Adjusted
Locks the arm to the operator and lets it be freed in an outage.
Signs it has failed: Arm moving independently of the hub, lever not staying pinned.
Primary arm, pipe arm and knuckles
Part replaced
Convert the output rotation into the swing of the leaf.
Signs it has failed: Bent flat bar, pipe slipping in the knuckle, worn pivot bolts, loose gate bracket.
Limit cams and limit switches
Adjusted
Set the open and closed positions.
Signs it has failed: Stop positions changing, gate running into its stop, switch not clicking.
60:1 gearbox and #40 chain
Serviced
Reduce motor speed and carry drive to the torque limiter.
Signs it has failed: Knocking at start and stop, chain slack, oil at the shaft seal.
Control board (ACPCB-UL or BLDC-ULPCB)
Repaired
Runs travel, reversing sensitivity, timer, master/slave and safety inputs.
Signs it has failed: No response with power present, timer or master/slave functions failing.
Batteries (DC PRO)
Part replaced
Run the gate through outages.
Signs it has failed: Few or no cycles on battery, low-battery indication.

Repair or replace your SW-300? The honest answer

An SW-300 rarely needs replacing for a slipping arm or a gate that stops short — those are torque limiter, arm and hinge problems. Replacement is the honest answer when the leaf is bigger or heavier than the SW-300 is rated for, or the gearbox is worn out.

Repair it when

Torque limiter slipping or overtightened
Quick-release lever or arm adjusting screw loose after an outage
Arm geometry or hinge problems making the operator strain
Board, limit switch or battery failures

Replace or upgrade when

An AC unit on a leaf over 800 lbs or 20 ft — the SW-300DC PRO is rated to 1,200 lbs at the same length, and the SW-350 class goes heavier and to 22 ft
A gearbox with worn internals knocking on every start
A solid leaf in an exposed spot that keeps overpowering the limiter, where a heavier-rated operator is the fix

Call Now — (214) 735-4314 Request a Free Estimate

Case studies

All-O-Matic repairs we have documented

Other All-O-Matic operators, written up in full — the same diagnose-first approach we take on a SW-300.

All case studies

Video
All-O-Maticresidential
All-O-Matic Stalling Mid-Travel — The Clutch Was Working Correctly
A gate that kept stopping halfway. The operator was fine; the gate was binding.
Read the case study

Our All-O-Matic work

Photographs from our own All-O-Matic jobs — a mix of models, not all of them the SW-300. None of it is stock.

How we diagnose and repair a SW-300

Free the leaf and feel the hinges
We open the quick-release lever and swing the gate through its full arc. Binding hinges or a dragging leaf explain most SW-300 complaints.
Check the arm
Lever, adjusting screw, knuckle set screws and the primary arm length against the closed and open bracket marks.
Set the torque limiter
From the slip point, tightened until the arm drives without slipping, then tested by holding the gate mid-cycle.
Limits, board and pair
Limit cams, reversing, safety devices, and — on double gates — each operator alone before re-linking master and slave.
Quote before work, test after
You approve the price first; we finish with repeated full cycles in calm conditions and a hold test on the limiter.

All-O-Matic warranty on the SW-300

All-O-Matic publishes a seven-year residential and five-year commercial warranty for the SW-300 AC and SW-300DC PRO, conditional on returning the warranty registration card within 30 days of purchase.

All-O-Matic’s written warranty covers defects in circuitry, motor, gearbox and workmanship; labor and shipping to the manufacturer are the owner’s cost.
Unregistered operators receive one year of parts coverage.
Warranty terms and the registration card are on each SW-300 product page at allomatic.net.

Our warranty on the repair

Every repair is backed by a clear written warranty. No hidden terms and no confusing fine print: what is covered is explained before we begin, and it is separate from whatever All-O-Matic covers on the operator itself.

What our warranty covers

The SW-300 in Dallas–Fort Worth conditions

Thunderstorm wind on swing leaves

North Texas storms throw strong gusts at driveway gates, and a solid or privacy-panel leaf acts like a sail. On an SW-300 the torque limiter is set to slip, so a gust can move the leaf against the arm. A limiter that has slipped repeatedly through a storm season may need resetting even though nothing is broken.

Hinge posts in clay

A swing operator lives or dies by its hinge post. When clay soil shrinks and swells, hinge posts lean, leaves sag and hinges bind at one point in the swing. An SW-300 then slips or stalls at that same angle every cycle. Resetting the post or re-hanging the leaf fixes what adjusting the operator cannot.

Grounding and lightning

All-O-Matic’s swinger manual requires a proper ground for every operator — a single, unspliced ground wire to a ground rod — and explains that it minimizes damage from a nearby lightning strike or static discharge. On an SW-300 that has lost a board in a storm, we check the ground before fitting another one.

All-O-Matic SW-300 repair across DFW & Surrounding Areas

Customer testimonials

Real Customers. Real Repairs. Watch Our Customers Tell Their Stories.

Real Shield Gate Repair customers describing the job in their own words, All-O-Matic jobs first.

Watch every customer video

All-O-Matic SW-300 repair questions

Why does my All-O-Matic SW-300 arm slip?

Because it is designed to. The torque limiter slips if the gate is held. When it slips in normal use, the nut has backed off, the quick-release lever is not locked, or the gate has become stiffer than when the limiter was set.

How do I open my SW-300 by hand in a power cut?

Remove the bolt or padlock from the arm lever and open the lever; the gate can then be pushed. When power returns, close and re-pin the lever and tighten the arm adjusting screw, or the gate will slip.

SW-300 or SW-350 — which do I have?

Look for a foot pedal. The SW-300 has a quick-release arm and an external torque limiter; the SW-350 has a foot pedal and a clutch inside the gearbox.

How heavy a gate can the SW-300 run?

All-O-Matic rates the SW-300 AC at 800 lbs and the SW-300DC PRO at 1,200 lbs, both up to 20 ft.

Can two SW-300s run a double gate?

Yes, as master and slave linked with a shielded two-wire cable. All-O-Matic says to set up each operator alone first and to wire all accessories to the master.

Is the SW-300 still made?

Yes. Both the SW-300 AC and the SW-300DC PRO are current on All-O-Matic’s site.

Request a free estimate for your SW-300

Leave your name and number, and tell us what the gate is doing. A technician will call you back. If the gate is stuck open or shut, calling is faster — someone always answers.

All-O-Matic SW-300 Swing Operator Repair in Dallas–Fort Worth

Is this a All-O-Matic SW-300?

SW-300 at a glance

What your SW-300 is doing, and what usually causes it

The motor runs but the arm slips and the gate hardly moves

The gate doesn’t open as far as it used to

It struggles or slips at the same spot every time

On windy days the gate stops or reverses

On our double gate one leaf lags or the pair gets out of sync

After a board was replaced, the gate runs the wrong way

The DC PRO gives up during a power cut

How the SW-300 works — and what that means for repair

The torque limiter: set to slip, on purpose

The quick-release arm and why it gets left open

Arm geometry decides how hard the SW-300 works

Limits and pairs of gates

SW-300 parts we repair, adjust or replace

Torque limiter (40A54TX2) and adjusting nut

Quick-release arm hub, lever and adjusting screw

Primary arm, pipe arm and knuckles

Limit cams and limit switches

60:1 gearbox and #40 chain

Control board (ACPCB-UL or BLDC-ULPCB)

Batteries (DC PRO)

Repair or replace your SW-300? The honest answer

Repair it when

Replace or upgrade when

All-O-Matic repairs we have documented

All-O-Matic Stalling Mid-Travel — The Clutch Was Working Correctly

Our All-O-Matic work

How we diagnose and repair a SW-300

Free the leaf and feel the hinges

Check the arm

Set the torque limiter

Limits, board and pair

Quote before work, test after