This one is quite simple - a tester for an LED strip for your TV repairs.
I had a bit of trouble with my LED TV. One of the LED strips went out, and my screen went black. Until I shone a flashlight straight into the screen and saw an image I had no idea what was wrong - the LEDs weren't working.
Let me apologise beforehand - I am not an electronics engineer, and I may make a few blunders along the way. I'm happy for any corrections or comments from more experienced makers!
3 9V batteries
A bit of wiring
Step 1: Wire Up Your Batteries
My LED strips ran on 27V. For a 32" TV, strips generally have 9 LEDs each, and each LED is a 3V load, and they are connected in series.
If you connect 3 9V batteries in series, you will have a power supply that is just over 27V.
I used bluetac to get the wires to keep in contact with the terminals.
Step 2: Add a Resistor and Maybe an LED
LEDs don't handle high currents very well, so you need to put a resistor into your circuit.
I used a breadboard for this, but technically you could wire your resistor in series to the terminals of your battery pack. I used a 68k ohm resistor because it was the first one I found lying around. I also found a small blue LED (probably rated at 1.5V) that I put in the circuit. This was to test a strip that had failed short, and was conducting, but not lighting.
Step 3: Power the Strips
Find the terminals on each LED strip and wire the battery pack to them. Remember, LEDs are diodes and only take current in one direction, so if a strip doesn't work, make sure you wire it in reverse first.
If a strip doesn't light, it's probably broken.