Bausch & Lomb 31-35-30 Microscope Light Source Transformer 5-6.5V AC 120V

Bausch & Lomb 31-35-30 Microscope Light Source Transformer 5-6.5V AC 120V

The Bausch & Lomb 31-35-30 is a step-down AC transformer designed to power the illuminator on the Bausch & Lomb 31-33-05 stereo microscope. It converts standard 120V AC wall power to the low-voltage AC output required by the microscope's lamp socket, with a front-panel rotary knob offering three intensity settings plus off. The unit is housed in a compact metal enclosure and connects to the microscope via a dedicated multi-pin output cable.

Specifications & What's Included

• Catalog No.: 31-35-30
• Primary (Input): 120V AC, 50/60Hz, 35 Watts
• Secondary (Output): 5.0–6.5V AC, 2.75A at 6.5V
• For use only with Bausch & Lomb 31-33-05 microscope
• 4-position rotary control knob: OFF, 1, 2, 3
• Two small output jack receptacles on rear panel
• Attached output cable with multi-pin white connector
• UL Listed (No. 385N)
• Made in USA
• Compact metal enclosure, benchtop form factor

Applications

Bausch & Lomb produced this transformer as a dedicated accessory for their stereo microscopes — particularly the 31-33-05 series — during an era when low-voltage incandescent illumination was standard in laboratory and educational microscopy. The transformer steps mains voltage down to the 5–6.5V AC range needed to drive the microscope's built-in lamp without overdriving it, and the multi-position rotary knob allows the user to adjust lamp brightness for different specimen types and magnification levels. These transformers are used today primarily as replacement power supplies for vintage Bausch & Lomb stereo microscopes that are still in service in school labs, hobby workspaces, and light repair/inspection stations. Finding a correct-voltage, correct-connector replacement for older B&L microscopes can be difficult, making original units like this one a practical solution for restoring a microscope to working illumination.