Quote Originally Posted by lerameur View Post
HI,
hope you are doing good.
I read a thread on this site concerning the 7805 overheating.
My 7805 is overheating even with a heat sink and I just have a LCD a pic chip and a RF receiving module. I tried the tricks they say but none is working.
I tried conencting the backlight directly to the 12v battery using a 150 IOhm resistor, or t o the 5V output of the 7805 with a 22 ohm resistor. Whils always keeping the LCD Vdd to the 5v of the 7805.
It heats op in every case ?
any ideas ?
Lcd 16 x2: UNIQ/eVision GC-1602I1
What is your input voltage to the 7805? 12v?
What do you mean by 'overheating'? It's actually overheating and shutting down or just getting hot?
Put a meter across the 5v and ground lines at their input to the board. What does it read when using the resistance setting? What does it read when using the diode-check (continuity) setting?

This should help get it narrowed down...