When a Cable Modem or Network Device Needs the Correct Replacement Adapter

A missing or failing power adapter can take a modem, gateway, or other connected device offline even when the equipment itself is still working normally. The LEI NU20-5120125-13 is a compact 15W AC/DC power adapter providing 12V DC at 1.25A, with P/N NU20-51120-3Y0F.

This model is particularly relevant to network equipment installations where the replacement needs to match the original 12V power specification. Public equipment documentation associates this exact model/P/N combination with cable modem platforms including SB5100, SB6120 and SBV5122.

Technical Specifications

OEM Replacement Compatibility

The following model and P/N are directly associated with this power adapter:

• LEI NU20-5120125-13
• P/N NU20-51120-3Y0F

For replacement identification, the model number and P/N should be compared with the existing adapter label. This is especially important because other LEI NU20 models can have different output specifications or connector configurations.

Compatible Devices

• SB5100 Cable Modem
• SB6120 Cable Modem
• SBV5122 Cable Modem / Voice Modem

These device associations are documented in a power-supply reference that identifies NU20-5120125-I3 with P/N NU20-51120-3Y0F for SB5100, SB6120 and SBV5122 applications.

Replacement & Maintenance Logic

A 12V network device that suddenly powers off, repeatedly restarts, or remains completely inactive may have a failed external power adapter rather than a defective modem or gateway. Replacing the adapter is a practical first step when the original unit has suffered cable damage, electrical failure, or simply become unavailable.

The important replacement criteria are the 12V output voltage, 1.25A current rating, correct connector configuration, and matching P/N. The current rating should not be treated as a standalone compatibility test. The connected equipment must be designed for the specified 12V input and the physical connector must match the device's power socket.

Frequently Asked Questions

What is the output of the LEI NU20-5120125-13?
It provides 12V DC at 1.25A, equivalent to a 15W rated output.

What is the P/N for NU20-5120125-13?
The P/N associated with this version is NU20-51120-3Y0F. The model and P/N should be compared with the original adapter label before ordering.

What devices are associated with P/N NU20-51120-3Y0F?
A published equipment reference associates this P/N with the LEI NU20-5120125-I3 configuration used for SB5100, SB6120 and SBV5122 cable modem platforms.

Is this a 15W adapter?
Yes. At 12V and 1.25A, the rated output is 15W.

Can any 12V 1.25A adapter replace this model?
Not necessarily. The replacement must also have a compatible connector, polarity, electrical characteristics, and appropriate physical fit. Matching the voltage and current alone is not sufficient.

What are common signs of a failing adapter?
Unexpected modem shutdowns, repeated restarts, intermittent operation, or failure to power on can indicate a problem with the external power supply. The adapter, cable, wall outlet, and device power input should all be checked.

LEI NU20-5120125-13 is a 15W AC/DC power adapter rated at 12V DC and 1.25A, with P/N NU20-51120-3Y0F. It is associated with cable modem equipment including SB5100, SB6120 and SBV5122, making it a replacement power source for compatible network devices that require the same 12V electrical specification and connector configuration.

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