Yamaha P140 not turning on...ideas??


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Hello all,

After returning home from a long trip my P-140 no longer powers on (no display lights, no sounds, nothing). It was plugged into the wall the whole time I was gone.

I have a copy of the repair manual so I opened it up and have verified that 12V is being received by the power(AMP) board. Also, the 9V and 5V regulators are outputting correct voltages when I press the "ON" button. And on the logic(DM) board I've verified that the 3.3V/2.5V and the 5V outputs are at the correct voltages as well. I took a guess that the Master Processor IC chip was the problem so I replaced that, but no luck.

Am I missing something obvious here? Anyone have any ideas? What else could cause the piano to seem completely unresponsive? Thanks in advance.
 
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Hey Gary, yeah i did a continuity check that the switch is working properly. Thanks.
 

happyrat1

Destroyer of Eardrums!!!
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Are there any state tables in that repair manual of yours?

Do you have a scope or a logic probe at your disposal?

Are you getting clock signals on all the logic pins?

Gary ;)
 
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Thanks Gary,
No state tables in the repair manual, unfortunately. And I don't have the equipment/expertise for the logic analysis you're suggesting, so perhaps it's time to bring it to the shop.
 

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