Need idea hove to..?

[phoenix_1]

Try increasing the 'startup pause', give the LCD more time to start itself before you start sending data. Double check your contrast wiring/voltage.

Hi skimask I was probe 1000 ms pause on startup and was probe on same pcb 2x16 chr it work and last solution is to lcd is fabric dead or bad ?!

pinout is same on 2x16 and that 4x20 and when 2x16 work and that not must be something with 4x20 wrong or maybe is problem in pbp2.50 maybe some bug ????

Really it is big problem for me...
Many thanks to all who was and will probe to help me !

Regards

p.s " The diference is only in define of no:. of lines betwin 2x16 and 4x20. and with same hardware 2x16 work and 4x20 have after reset time back all chr on screen !"