Mighty Mule RB570 18 VAC 40 VA Transformer for UL Gate Openers
The RB570 is the plug-in 18 volt AC transformer used on many Mighty Mule, GTO, and Linear Pro battery-backed gate opener installations. In these systems the transformer does not normally run the motor directly. It feeds the control board charging circuit so the gate opener battery can stay charged between cycles. When the transformer fails, a gate may continue to run for a short time from the battery, then slow down, stop, or show low-battery behavior.
This part is most often ordered when the original transformer is lost, weather damaged, shorted, or no longer producing the expected AC output. Correct fitment matters because some newer Mighty Mule models use different power supplies, and some older non-UL systems may not use this transformer style. Always compare the model number, control board generation, and original transformer rating before installing a replacement.
Compatible With
Commonly associated with select UL-rated Mighty Mule, GTO, and Linear Pro swing and slide gate opener systems that use an 18 VAC / 40 VA charging transformer.
- Mighty Mule FM500 and FM502 gate opener systems
- Mighty Mule MM500 and MM502 series applications where the 18 VAC RB570 transformer is specified
- Mighty Mule MM560 and MM562 series applications when confirmed by manual or parts diagram
- GTO / Linear Pro SW2000, SW2500, SW3000, SW4000, and SW4200XL family systems when the 18 VAC transformer is specified
- GTO / Linear Pro SL1000 and SL2000 slide gate opener systems when matched to the UL power configuration
- Commonly associated with PRO-SW2500, PRO-SW2502, PRO-SW3000XL, PRO-SW3200XL, PRO-SW4000XL, and PRO-SW4200XL parts listings
- Select older Mighty Mule swing and slide openers after UL325 generation changes where RB570 is called out
- Not the correct replacement for all newer MM271, MM272, MM371, MM372, MM571, or MM572 style power supply systems unless the manual specifically calls for RB570
Features & Specifications
| Manufacturer | Linear / GTO / Mighty Mule |
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| Product Type | Plug-in gate opener transformer |
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| Part Number | RB570 |
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| Application | Battery charging transformer for compatible automatic gate operators |
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| Voltage | 18 VAC output |
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| Power Rating | 40 VA |
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| Input | Standard plug-in AC supply, verify local voltage and outlet condition |
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| Compatible Operator Type | Select UL-rated battery-backed swing and slide gate openers |
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| Notes | Used for charging circuit applications, not as a universal DC power supply |
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Also Known As / Related Part Numbers
- RB570
- FM352 RB570
- GTO RB570
- Mighty Mule RB570
- Linear Pro RB570
- 18 VAC 40 VA transformer
- 18 Volt / 40VA transformer
- SW2000 transformer
- SW3000 transformer
- SW4000XL transformer
- SL1000 transformer
- SL2000 transformer
Technician Note
If the battery will not stay charged, check the outlet, transformer output, wiring to the control board, battery age, and charging circuit before assuming the transformer is the only failed part.
Before Ordering Checklist
- Confirm the gate opener model and control board generation.
- Match the original transformer rating to 18 VAC / 40 VA.
- Inspect the power wiring, plug, outlet, and low-voltage cable for damage.
- Do not substitute a DC adapter for this AC transformer.
- Verify whether the opener is a newer Mighty Mule model that uses a different power supply.
Important Ordering Warnings
Transformer compatibility varies by operator generation. Similar Mighty Mule model names may use different power supplies depending on production date and control board type.
Professional Advisory
Low-voltage transformer replacement is usually straightforward, but diagnosis around AC power, charging circuits, damaged wiring, or repeated transformer failure should be handled by a qualified gate technician.
Product Q&A
What does the RB570 transformer do?
It supplies 18 VAC to the compatible gate opener control board so the board can maintain the system battery charge.
Is RB570 compatible with every Mighty Mule opener?
No. It is used on many UL-rated Mighty Mule, GTO, and Linear Pro systems, but newer and older models may require a different power supply.
Can I use a 12 VDC adapter instead of this transformer?
No. This part is an 18 VAC transformer for systems designed around that AC input.
What symptoms point to a bad transformer?
Common signs include a battery that will not stay charged, low-battery faults, slow operation after several cycles, or no charging voltage at the control box.
Should I replace the battery at the same time?
If the battery is old, swollen, weak under load, or has been deeply discharged, it should be tested or replaced along with correcting the charging issue.
