Yamaha PSR S775 No Sound From Output Jack qnd Head Phone Jack

Hello Gurus, please i need your help on a Yamaha PSR S775 keyboard with sound its speakers BUT NO SOUND FROM OUTPUT JACKS & HEADPHONE JACK PORT.

Attached are few pictures of the sound section on the mainboard.

Please kindly advise what component(s) could be replaced.

Thabk you for your expertise advise on this :pray::pray::pray:

Possibly the AJACK board has a problem. I would change that first. Part ZP451401. About $53 + shipping from yamaha24x7.com

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try this trouble shooting first.


Then try the factory reset.

Last, see if the jack has a broken or dry solder connection.


I am pretty sure there is a menu option to disable various outputs


As pointed out, there is a Global Setting to Mute the Outputs & Headphones. If this does not work, the DAC (Digital to Analogue Converter) is the only component that the Outputs & Headphone have in common, but that the speakers do not use. This component is IC807 - AK4396 surface mount component on the DMM PCB. Before the HP DAC, the digital signal splits off to a separate Speaker DAC (still working); after the HP DAC, the signal splits to two separate Op-Amps - one for Headphones and the other for the Outputs (neither working). Good luck.


I believe the AJack is actively okay. Thebissue should be from the board.

Thanks for this. But didn’t suffice still. :disappointed:

Thanks a lot.

I did check this, still same situation. :see_no_evil:

Thanks a lot.

I will give it a careful approach. This should work as its so close to my assumption but i didnt want to attempt first until i see a clarification on it.

Thanks I’m so grateful.

BTW - did you try Factory Reset !?

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No, but doesn’t seems to me like a solution for it. Due to the motherboard readings.

Thanks i did something around this and change few other components. It’s now working fine.

What did you change ?