Dacor ER48DSH/NG indicator light Not working

This new Dacor ER30DSH/NG Gas range has the signature Dacor blue indicator lights which illuminates each knob when the surface burner is turned on. The indicator light is very important on a gas range to show the user that a burner is on especially when the burn is on a Low simmer when a flame is nearly invisible. Time to call for service.

New LED with larger black varistor

The indicator lights are low voltage LED controlled by cherry micro switches on each gas valve.  As the knob is turned a cam on the gas valve triggers the switchs allowing voltage to the LED. With these LEDs a small voltage change results in a large change in current.  It is therefore important that the power source gives the right voltage.  If the voltage is too high the current will go above the maximum rating, heating and potentially destroying the LED. As the LED heats, its voltage drop decreases further increasing current. LEDs should only be connected directly to constant-voltage sources. A varistor are a simple way to stabilize the LED current. A varistor is a non-ohmic variable resistors. known as a metal oxide varistor, or MOV.  This contains a zinc oxide grains, in a matrix of other metal oxides, between two metal plates. The boundary between each grain forms a diode junction, which allows current to flow in only one direction.  The mass of oriented grains is electrically equivalent to a network of back-to-back diode pairs, each pair in parallel with many other pairs. When a small or moderate voltage is applied across the electrodes nonlinear current-voltage in which the MOV has a high resistance at low voltages and a low resistance at high voltages stabilizing the voltage and  absorbing small voltage surge. Working like a mini capacitor . Varistors do not absorb a significant percentage of a lightning strike, but they can stabilize low voltage.

Cherry micro switches and cams on gas valves

Dacor has revise the varistors on there LED three times each time adding a larger capacity varistors to protect the LED. Dacor tech line also recommended that we replace all LED when one is burn out. Remove the four drip pan trim.then the two center porcelain covers slid forward lift up at the rear then side back to remove. remove the burner and two crown burner there is a tool under the right side toe panel. Lift up the three drip pans and four screws remove the front brace. This gives you access to all 6 pn# 100121 LED lights they just unplug. reverse the steps and tested each indicator lights.

Dacor crown burner with drip pans removed

(Parts used)
6 each pn#100121 LED lights
(Time )
45 min
(Tools)
#2 Phillips Screwdriver

Crown burner tool (under toe panel)