Haag-Streit Power Supply & Fixation configuration: it's all about resistors and jumpers

Haag-Streit slit lamp chinrest fixation is either a Bulb or an LED.
If it is LED it needs a RESISTOR in the circuit or the voltage will blow the LED.
If it is Bulb, it needs a JUMPER to bypass the resistor or it will not light up.
Depending on what type of chinrest you are using will determine what to configure your power supply.
Very early models of power supplys did not have a resistor in the circuit. They were designed for bulb fixations only.
The newer models of power supplys have a resistor built in the circuit but include an optional jumper for use in either type of fixation.
*If you replace the power supply or the chinrest, always make sure you have the correct configuration for the appropriate type of fixation.
This also applies to the newest LED conversion kits offered by Haag-Streit.