AT&T Technologies 3301A 104200118 Power Module 20V 2A 40VA HP DeskJet 500 120V

AT&T Technologies 3301A 104200118 Power Module 20V 2A 40VA HP DeskJet 500 120V

The AT&T Technologies 3301A (part number 104200118) is a safety isolating transformer power module rated at 20V AC, 2.0A, 40VA output. It takes a standard 120V 60Hz input and steps down to a low-voltage AC output through an isolated transformer design, making it a Class 2 device per UL standards. This unit was manufactured by AT&T Technologies and is compatible with HP DeskJet 500 Series printers.

Specifications & What's Included

• Manufacturer: AT&T Technologies
• Model: 3301A
• Part Number: 104200118
• Type: Safety Isolating Transformer / Power Module 1
• Input: 120V AC, 60Hz, 0.40A
• Output: 20V AC, 2.0A, 40VA
• Safety Class: Class 2 (UL)
• Connector: Right-angle multi-pin output connector (attached cable)
• Compatible With: HP DeskJet 500 Series printers
• Country of Manufacture: Mexico
• Date Code: 89KZ22 (circa 1989)
• Included: Power module with attached coiled cable and output connector

Applications

The 3301A is a low-voltage safety isolating transformer designed to power peripheral devices — in this case, HP DeskJet 500 Series inkjet printers, which were among HP's earliest consumer and small-office inkjet models introduced in the late 1980s and early 1990s. Safety isolating transformers of this class provide galvanic isolation between the mains supply and the load, limiting output current and voltage to Class 2 levels (inherently limited power) as defined by UL standards — a standard requirement for low-voltage printer and peripheral power circuits of this era. This type of AC power module delivers AC output directly (not rectified DC), which is typical for certain printer mechanisms that require AC for motor or solenoid operation. These units are primarily sought today for servicing or restoring HP DeskJet 500 Series printers, which retain a following among vintage computing collectors and those maintaining legacy office equipment.