i got a hr550 receiver for chistmas, and decided to throw up a tutorial on how to do this.
Soldering iron (solder, flux)
hot glue (ultra high temp.. if you do not have a 220watt glue gun and high temp glue, skip it. the amp gets extremely warm, and melted glue and components just dont mix)
clear acrylic plexiglass sheet (cd cases will work just fine)
heat shrink tubing
(reflective flashlight bezel/aluminum duct tape optional-only for brightness)
(I unfortunatly finished my project prior to taking pictures of it, so some of the steps are already accomplished)
Step 1: Wiring the LEDS/Power Source
You will be working with electricity that can kill you.
If you do not know how to solder, do not do it. Learn how to do what you need to do first, so you dont end up ruining the project. there are a number of 'how to solder' tutorials in instrucables.com.
If you damage something, youre on your own. The only person that should take the blame is you.
Obviously, the first thing you need to find is a power source.
I wanted the backlight to turn on when the receiver turned on.
remove the case and look towards the sirius/xm radio inputs. Both these inputs carry a low voltage power source, and is ideal for the leds.
If you are using sirius, do not tap it for power, look somewhere else.
I salvaged some leds from a rope light i bought on christmas clearance. ($1.90 for 150 led rope).
I had no idea what the forward voltage or current of them.
There is a trick to measure the forward voltage by soldering a 1k ohm resistor to the positive lead, hooking it up to a 9v battery and using the multimeter, determine the voltage. (it will drop by exacly 1k ohm) Once again, there are plenty of tutorials on how to use a mutlimeter to find these things out.
On the current factor, you basically have to take a guess. This site has a basic overview of what certain leds are:
After you find a general starting point with that information, head to http://ourworld.compuserve.com/homepages/Bill_Bowden/led.htm and plug in the info.
This will tell you what size resistor you will need.
(never mismatch leds. If you mismatch them, you may have an issue of using the wrong resistor and watching the lower voltage of the leds burn up)
I determined my leds were .60ma at 3.5volts each. (total of 3)
add up the volts-11volts total
12volt power supply
I need a resistor that is 820ohms at 0 watts
(sorry the picture quality on this isnt the best.. new camera, havent had much time to figure the settings out)