Chosen Solution
Answering the usual questions: Do you have 2.7v to 3v enable signal on pin 17 of U7700? YES 3.3v Do you have 5v on pins 5 and 18 of U7700? » YES R7733 0 ohms? »» YES What voltage do you have on backlight output, pin 1 of LCD connector? 0v? 12v? 20v? 27v? »> 0v
Check voltage on pin 2 of pull up resistors for i2c_bklt_sda and i2c_bklt_scl. Should both be 5v. If not 5v, test resistance of pull ups 2.4Kohms. If those readings are good, check the trace continuity from pull up resistors to connector.
