It S On Standby Its Only Work With The Remote Sony Receiver

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Hi I have Sony hcd gtr88 cd it’s on standby its only work with the remote but the front panel standby power button doesn’t work what could be the fault I have changed the button still not working

Hi, You need to check the wiring for the power key through the connectors from the display board (where the key is mounted) through to the mainboard. The path is on the ADKEY0 wire that goes from CN1105 pin 15 on the display board to CN405 pin 9 on the mainboard. This lead then goes to R497 and then onto the IC401 controller IC. See p.23 & p.31 of the service manual to view the schematics which show how the Power button (along with the other control panel buttons) signal to the controller. The power button signal with no extra resistance on the lead but each subsequent function button inserts more resistance on the lead when it is pressed and the controller then knows what function is desired. See the image below, the red arrows are the ADKEY0 lead and the green arrows show the extra resistances used for the other key function but they are ion the same lead.

(click on image to enlarge for better viewing) If the wiring checks out i.e. no loose connections or dry joints then you need to check the path electrically right though to the controller IC.