Cisco PWR-3900-DC/2 DC Power Supply Router
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PWR-3900-DC/2 Cisco DC Proprietary Power Supply Refurbished

Availability: In Stock
Part Number#: PWR-3900-DC/2
List Price was: $855.81
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Short Description:
PWR-3900-DC/2 3925/3945 Series Integrated Services Routers DC Proprietary Power Supply (Secondary PS) | Made by Cisco | Refurbished
Product Condition:
Warranty provided by ALLHDD.COM:
90 Days

Technical Specifications and features of Power Supply

The PWR-3900-DC/2 Cisco DC Proprietary Power Supply is a power supply unit that provides backup power to Cisco 3900 series routers. This unit is designed to fit in a standard Cisco 3900 series rack mountable router and provide an additional power source for the device. The following are the technical specifications and features of the PWR-3900-DC/2:

Technical Specifications:

  • Input Voltage Range: 36-72 V DC
  • Output Voltage: +48 V DC
  • Output Current: 83 A
  • Output Power: 4000 W
  • Efficiency: 94%
  • Operating Temperature: 0 to 50°C
  • Dimensions: 5.3 x 4.4 x 1.75 inches (13.5 x 11.2 x 4.4 cm)


  • Dual Inputs: The PWR-3900-DC/2 has dual inputs which provide increased redundancy and reduces the risk of power interruption.
  • High Efficiency: The power supply unit has a high efficiency of 94% which reduces the amount of power lost as heat, thus improving reliability and reducing maintenance costs.
  • Hot-Swappable: The PWR-3900-DC/2 is hot-swappable, allowing users to replace it without having to power down the router.
  • Compact Design: The compact design of the PWR-3900-DC/2 makes it easy to install and maintain.

The PWR-3900-DC/2 is a reliable and efficient power supply unit that provides backup power to Cisco 3900 series routers. The dual inputs, high efficiency, hot-swappable design, and compact form factor make this power supply unit an ideal choice for network administrators looking to improve their network's reliability and maintainability.

Troubleshooting and Maintenance


  • No Power: Check if the power cable is connected properly, and if the AC voltage input is within the acceptable range. If the problem persists, the power supply may be faulty and need replacement.
  • Overheating: Check the ventilation around the power supply to ensure adequate airflow. If the problem persists, it may be due to a malfunctioning fan or a damaged thermal sensor, which would require repair or replacement.
  • LED Indicator Not Illuminated: This could indicate a failure in the power supply or the system. Check the wiring and connections, and if the problem persists, the power supply may need to be replaced.


  • Regular Cleaning: Dust and debris can accumulate over time and affect the cooling performance of the power supply. Regular cleaning is recommended to maintain optimal operation.
  • Firmware Upgrade: To ensure the power supply is running the latest firmware, perform regular firmware upgrades to address any known bugs and improve performance.
  • Power Supply Replacement: If the power supply is damaged or has reached the end of its life cycle, it should be replaced with a new one to ensure optimal performance and reliability.

Reliability and Durability

Reliability refers to the ability of a device to perform its intended functions consistently and accurately over time. The PWR-3900-DC/2 Cisco DC Proprietary Power Supply is designed to be a reliable power source for Cisco equipment, ensuring that the connected devices are powered up and running smoothly without interruption. This power supply has a high reliability rating and is built with high-quality components, ensuring consistent and accurate performance even under extreme environmental conditions.

Durability refers to the ability of a device to withstand wear and tear, environmental factors, and general wear over time. The PWR-3900-DC/2 Cisco DC Proprietary Power Supply is built with rugged, high-quality components and is designed to withstand extreme environmental conditions such as temperature fluctuations, dust, moisture, and other harsh conditions. This makes it a durable power source for your Cisco equipment, ensuring that it continues to provide reliable performance for years to come.

General Information about this Cisco PWR-3900-DC/2

  • Manufacturer: Cisco
  • Model Number or SKU # PWR-3900-DC/2
  • Product Name PWR-3900-DC/2 Proprietary Power Supply
  • Product Type: Proprietary Power Supply
  • Input Voltage Type DC
  • Form Factor Internal


  • Cisco Integrated Services Routers:
  • 3925
  • 3945

Please contact us over the phone or ask for live chat/help if you have any questions about the estimated time of arrival for any "lead time required" item.

About Refurbished Products

Refurbished products are typically refurbished by an Original Manufacturer or an affiliate of the manufacturer or 3rd party facility. This product may have minor blemishes due to normal product usage and doesn't necessarily come with documentation and software unless indicated, but has been well tested and generally has never had any defects.

All the devices in the IT system need electrical power to function. That power gets into them through a power supply, which is tasked with converting the AC mains voltage to regulated DC voltage. A router, being one of the networking devices, also requires power to function. It can have other powered devices attached to it.

Built-In Power Module

Most computers and data center equipment have built-in power supply modules. These modules have receptacles at the side of the chassis where a power cord from the main outlet is attached. The built-in router power supply needs to be very energy-efficient to reduce internal heating. Remember that any electrical power that is not converted into output is lost as heat.

Redundant Power Supply

Redundant power supply (RPS) are standalone power units used for standby power supply to a router. It requires a cable to connect it to the mains power socket outlet and a different one connecting it to the router. Usually, these RPSs have backup batteries to power the router when there is a power outage.

Since it is a backup power supply, it is designed with an intelligent monitoring system. This system sounds the alarm when the mains power disconnects, the battery runs low, and the battery is nearly dead. It also auto disconnects loads when the battery voltage drops below 11V. However, these functionalities vary from one router power supply model to the other and also depend on the capacity of the internal batteries.

Increased System Reliability

If you find an excellent router power supply, your system can be more stable. It can be even more reliable with a redundant power supply to back it up when there are power outages. The intelligent alarm system also makes it possible to act quickly when the battery is running low. Generally, a reliable power supply system will reduce downtime.

Budgeting for Router Power Supply

The prices for power supply vary from one model to the next, and you don't have an option. You need the appropriate router power supply for your router model. These differences have made shopping very difficult, but ALLHDD has made everything simple.

If you are looking for an affordable router power supply, then we got you covered. At ALLHDD, you will find any computer hardware you need. We are also available to help our customers in shopping for these computer hardware products. Contact us for more information!

Here, you can check more available conditions of your desired product PWR-3900-DC/2 at a competitive price. We are trying our best to meet your needs on the enterprise-level computer, server, data centre, and networking hardware. You are welcome to ask our live chat or get live representative support over the phone.


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ALLHDD guarantees that the products will not have defects in material that will affect the product's functionality during the Standard Warranty Period. The warranty period starts when the merchandise/items from our warehouse.

What does ALLHDD.Com warranty cover?

30-days to 3 years warranty:

Replacement or refund. In the case of material defects, we will try to replace the product first. The product will be replaced before the expiration of the original warranty. For any failure of hardware, if we cannot process the replacement of the product(s)/model(s), we will refund the original selling/invoiced price. The shipping costs and sales tax, if any, are non-refundable. ALLHDD retains the right to decide whether the item(s) will process for replacement or refund.

What is not covered by our warranty?

The reason why our warranty does not cover any problem caused by the following conditions:

(a) misuse of hardware; accidental damage; carelessness product(s) damage; shock; temperature beyond the specification of any product; faulty installation; operation; modification of goods;

(b) any misuse outside the instructions in the user manual for any specific product;

(c) damaged caused by other hardware or equipment. The warranty will void if the item is returned with physical damage, damage to the retail box, removed from the box, counterfeit labels/labelled by them, or any modifications of internal and external covers. Data loss or damages to any other equipment we do not cover by our offered warranty.

What is the Manufacturer/Brand Warranty?

In general, a manufacturer's warranty service/support is a written guarantee to the buyer of a product. Its terms assure the replacement or repair of the product, if necessary, within a specified period after the purchase (2-5 years depending on the brand/manufacturer). It is typically included in the price of the product. Products are brand new and sealed and the original manufacturer box is complete with the Manufacturer's genuine warranty. For most of the brand new/retail products that come with the manual and box, exceptions may apply (i.e., Cisco, Juniper Networks).

For the server parts (i.e., Dell, HPE) to get Full coverage of the warranty server must have a full 3- 5 years warranty. However, ALLHDD.COM will cover the warranty duration if any Manufacturer doesn't support the advertised warranty and there is no refund for those.
Final Sale items are non-returnable/refundable in any situation. Any question? please ask our team before the shipment.

Important notes:

We can provide additional warranty service/support for any product you purchase from us if you need additional warranty coverage before finalizing the order from ALLHDD.Com. You need to ask in live chat/help or call us for more information.

Individual product warranty mentioned on each item product description page/detail page.

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FedEx Shipping Options:

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Worldwide Shipping Options:

UPS®/FedEx® International Economy

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UPS®/FedEx® International Priority

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UPS®/FedEx® Ground Shipping Canada

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Important notes:

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