Acer A221HQV Acer A221HQV LCD Monitor Service Guide - Page 43

5. Troubleshooting (continued) 5.2.6 Abnormal plug and play operation 5.2.6.1 Abnormal plug and play operation for VGA ACER A211H/A221HQ 41 Go to contents page Confirm the host computer supplies DDC/CI mode. Failure Point NG The host machine is not communicated in DDC/ CI mode. OK Check the voltage on CN302 pin 9, that is DC 5 V. Failure Point NG The VGA video cable is failure. OK Check the voltage on I304 pin 8, that is DC 5 V. OK Failure Point NG 1) Printed wire broke between I304 pin 8, D307 and CN302 pin 9. 2) D307 is failure. Check the signals if is high level on CN302 pin 12, 15, that is I2C data / clk signal. Failure Point NG The VGA video cable is failure. OK Check the output signal of I2C data / clk on I304 pin 5, 6. Failure Point NG I304 is failure. OK Failure Point 1) Printed wire broke between I310 pin 58, 59, I304 pin 5, 6 and CN302 pin 12, 15. 2) I310 maybe failure. 3) R334 or R335 is open. 4) C334, C335, R332, R333 is short.