Hello, sorry for taking so long in answer again, this are my conclusions:
First of all this is the noise signal I got in my oscilloscope between 2 points in the ground when the relay turn off.
This is the schematic of my circuit
Real life circuit
Im using a small water pump (127V, 3W) used in little fountains like fen shu and stuff. It looks like this:
MarkT:
Replace that 1N4007 with a fast recovery rectifier, its too slow.
I changed the 1n4007 diode for a 1N4937 (Fast recovery rectifier) but the ground problem is the same.
I also tried adding some decoupling capacitators (3, one near the LCD, one near the relays, and one near the power supply) all the 3 are ceramic capacitators of .1uF (50V). With this the problems seems to minimize but it stills affect the LCD randomly.
I also tried adding the snubbers, but i found alot of diferent types of connections, I tried this:
All my snubbers consist of .1uF ceramic capacitor (50V) and a 100ohms resistor (1/4w)
In snubber #1 (parallel to the load): My resistor and capacitor burned in 5 secs.
In snubber #2 and #3: The problem in ground persists.
If anyone could help me I would be very grateful.