OEM Class 2 Transformer | 50 VA | 24VAC Secondary | Replacement for Compatible Detex Power Supplies

Restore a compatible Detex power-supply system with the Detex 800 Series Replacement Transformer, a genuine factory replacement component used in Detex electrified-door power supplies.

Detex identifies Part Number 104254 as the replacement transformer for the 90-800 Filtered Regulated Power Supply. The transformer accepts the power-supply's incoming line voltage and provides the 24VAC secondary power required by the Detex power-supply circuit board.

This listing is for the transformer only and is intended for repair and replacement of compatible Detex power-supply assemblies.

Key Features

• Genuine Detex replacement component

• Detex Part Number 104254

• Replacement power-supply transformer

• Class 2 transformer

• 50 VA rating

• Provides 24VAC secondary output to compatible Detex power-supply electronics

• Factory replacement for the Detex 90-800

• Used in compatible Detex power-supply/controller architecture

• Designed for commercial electrified-door systems

• Ideal for repair and refurbishment

• Transformer only

• Circuit board and enclosure not included

Detex Part Number 104254

Detex factory documentation specifically identifies:

Replacement Transformer: 104254

for the 90-800 Series filtered and regulated power supply.

Detex also continues to list the 104254 transformer in newer power-supply maintenance documentation along with replacement power-supply and controller boards.

Class 2 – 50 VA Transformer

Detex specifies the 104254 as a:

Class 2 – 50 VA Transformer

The transformer is factory-selected and rated for proper operation with the compatible Detex power-supply system.

Using the correct Detex replacement helps maintain the intended electrical characteristics of the complete power supply.

24VAC Secondary Output

The transformer supplies:

24VAC to the Detex power-supply circuit board

The PCB then rectifies, filters, and regulates this power to provide the required DC output for compatible electrified-door equipment.

Important Distinction

The transformer itself supplies 24VAC.

The complete Detex 90-800 power supply provides:

24VDC regulated output

after the transformer output passes through the power-supply PCB.

90-800 Power Supply Application

The Detex 90-800 is a filtered and regulated commercial power supply designed to provide:

24VDC at up to 1 Amp continuous output

for compatible electrified door hardware.

The 104254 transformer is one of the primary replaceable components inside this assembly.

Detex identifies the major 90-800 service components as:

• 104254 – Replacement Transformer

• 104252 – Replacement Power Supply PWA

• 104267-2 – Replacement Fuse

Compatible Electrified Door Applications

When installed in the appropriate Detex power supply, the transformer supports systems used with compatible:

• Delayed-egress exit devices

• Electrified exit devices

• Access-control doors

• Electromagnetic locking systems

• Electric door hardware

• Commercial life-safety openings

Detex identifies the 90-800 for use with compatible ED, EE, and EM products.

Product Specifications

Manufacturer: Detex
Part Number: 104254
Product Type: Replacement Transformer
Transformer Classification: Class 2
Rating: 50 VA
Secondary Output: 24VAC
Confirmed Power Supply Compatibility: Detex 90-800
Primary Application: Detex Electrified Door Power Supply
Installation: Inside Compatible Power-Supply Enclosure
Use: Replacement / Repair / Service
Component Only: Yes

Important Compatibility Note

Detex has produced several Series 800 power supplies and controllers, including:

• 80-800

• 81-800

• 82-800

• 83-800

• 84-800

• 85-800

• 90-800

• 10-800

• 11-800

• 12-800

These systems do not necessarily use identical transformers or internal configurations.

The 104254 is specifically factory-confirmed for the 90-800 and certain later Detex power-supply assemblies. Always verify the existing transformer part number and controller documentation before installing it in another Series 800 model.

Replacement Applications

Replace the transformer when the existing component has been properly diagnosed with symptoms such as:

• No secondary voltage

• Open transformer winding

• Physical transformer damage

• Burned or overheated transformer

• Failed primary or secondary winding

• Transformer-related power-supply failure

Do not automatically replace the transformer when a power supply has no DC output.

Other possible causes include:

• Failed fuse

• Failed power-supply PCB

• Incorrect incoming voltage

• Shorted output wiring

• Shorted connected hardware

• Fire-loop control condition

Detex specifically recommends checking connected loads and wiring when troubleshooting power-supply output problems.

Installation & Electrical Safety

This component is installed inside equipment containing line voltage.

Installation and testing should be performed by qualified personnel familiar with commercial access-control and electrified-door systems.

Before servicing:

• Disconnect incoming AC power

• Verify power is removed with a meter

• Confirm the original transformer part number

• Inspect fuses and wiring

• Confirm primary input voltage

• Verify secondary output before reconnecting the PCB

• Correct any downstream short circuits before energizing the replacement

Detex warns that hazardous voltage can remain inside the enclosure whenever the building power feed is energized, even if the power-supply switch is turned off.

What's Included

(1) Detex 104254 Replacement Transformer