How to Install a Backlight on a Simpson M235

The Simpson M235 is a wall-mounted digital panel meter that is used to measure voltage and current of power supplies or large appliances. The M235 measures six different current ranges. The meter features a compact case and slide out mount design for easy installation. The liquid crystal display (LCD) is back-lit by a red LED mounted to the rear of the display area. If this LED stops working, it is replaceable.

Screwdriver
Soldering iron
Tweezers
Replacement back light LED

Instructions

- 1
  Turn off the power from the circuit breaker to the breaker that controls the meter.
- 2
  Remove the front mounting screws from the meter with a Philips screwdriver and then set the screws aside. Slide the meter out from its wall mount.
- 3
  Remove the wire leads attached to the back of the meter with a screwdriver.
- 4
  Set the meter on a table or work bench and then remove the meter's casing screws. Slide the case off to expose the inside of the meter.
- 5
  Plug in the soldering iron, let it warm up and then touch the tip of it to the solder joint holding the back light LED in place. As the joints soften, use a pair of tweezers to remove the old LED.
- 6
  Set the new LED in place on the circuit board with the tweezers, with its leads attached to the circuit board holes. Hold the solder just at the base of the LED leads and melt a small amount onto the leads.
- 7
  Slide the meter's case back on and screw in and tighten its retaining screws with the screwdriver.
- 8
  Reconnect the wiring from the wall to the back of the meter and then slide the meter back into its wall mount. Replace the wall mount screws with the screwdriver.
- 9
  Turn the power back on at the circuit box and check to make sure the new LED is working.

My Brand New Air Conditioner Isn't Cooling

A Leak in an Air Conditioner

Air Conditioners