failed LEDs

A project log for Tomtom GO730 GPS display backlight repair

Ever ended up in a herd of scared cows after driving down a steep bumpy trail by following tomtom directions? I did.

rawerawe 10/30/2014 at 07:450 Comments

Measuring the voltages across the single backlight LEDs, it looks like the first one and the last one in the chain are high-resistance-ish. With a power supply in constant current mode, I was able to check the single LEDs for operation.

Indeed, the two LEDs were faulty (?!?!).

The next logical step: replace/bridge them:

I opted for 0805 resistors in the 10...20 Ohms range (12R7) :

aaaand voila - Press and keep pressed the power button to let the unit boot to a summary screen. Releasing the power button continues the boot process.

I still have to replace the burnt 5V USB input protection diode.

Fun fact: It now tells me the TFT type *facepalm*: Sharp lq043t1dg01