Author Topic: Yamaha digital piano produces no sound  (Read 5990 times)

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Offline metrologist

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Re: Yamaha digital piano produces no sound
« Reply #50 on: May 13, 2022, 09:19:51 pm »
loading the supply line?
 

Online Audiorepair

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Re: Yamaha digital piano produces no sound
« Reply #51 on: May 14, 2022, 12:01:18 am »
Unfortunately, buying cheap unknown parts just introduces more unknowns into the unknown unknowns.

Welcome to the real world.
 

Offline james_s

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Re: Yamaha digital piano produces no sound
« Reply #52 on: May 14, 2022, 12:08:21 am »
Try removing the new DACs and see if the supply voltage bounces back. Are these through-hole parts? Is it possible you ripped out the through-hole plating on one of the power pins?
 

Offline PianomancerTopic starter

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Re: Yamaha digital piano produces no sound
« Reply #53 on: May 15, 2022, 01:03:50 am »
I know the old DACs were getting 5v, and now it's 1v. I resoldered/checked the connections but still am getting just distorted quiet sound. They are SMD so it's a pain to remove the chips entirely especially with the limited equipment I have, so maybe I should just desolder the 5v supply on one of them to check one at a time? Is it possible one of them is bad and bringing the other down with it?
 

Offline PianomancerTopic starter

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Re: Yamaha digital piano produces no sound
« Reply #54 on: May 15, 2022, 03:18:08 am »
Here's the sound
 

Offline james_s

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Re: Yamaha digital piano produces no sound
« Reply #55 on: May 15, 2022, 06:50:05 am »
My guess is the DACs you got are counterfeit, some other IC that has the wrong pinout and just happens to be able to output something recognizable. I worked on an arcade board once and was surprised to find that just connecting an amplified test speaker to the digital line into the DAC resulted in badly distorted but recognizable audio.
 

Offline PianomancerTopic starter

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Re: Yamaha digital piano produces no sound
« Reply #56 on: May 16, 2022, 04:46:10 pm »
Well that's disappointing if that's the case, especially that both of them would be duds. So I have to believe if I had ordered different ones it would be a done job. I'm done testing though, as I have run out of time for this project. Thanks a bunch to everyone for your help and encouragement. It's hard to go at such a project alone!
 

Offline james_s

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Re: Yamaha digital piano produces no sound
« Reply #57 on: May 17, 2022, 05:14:00 pm »
Where did you buy them? A large amount of the harder to find parts available from Chinese ebay sellers are counterfeit, they'll take whatever junk IC they have a lot of in the right package and relabel it as something more valuable. I don't see why you'd set it aside now, it sounds like you've solved the puzzle, the problem is bad DACs, and all you have to do is acquire a couple of the correct replacement parts and install them and you're done.
 

Offline PianomancerTopic starter

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Re: Yamaha digital piano produces no sound
« Reply #58 on: May 17, 2022, 08:02:38 pm »
I got them from a Chinese seller on ebay... not the most reputable source, but these chips are a little hard to come by and not as cheap as they ought to be. The problem is ordering new ones requires more weeks of waiting, and there's no guarantee the new ones would be good either. It's just time I don't have now. At least it's good experience to have going forward if I ever tackle such a project again.
 

Offline james_s

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Re: Yamaha digital piano produces no sound
« Reply #59 on: May 18, 2022, 12:36:09 am »
Well get the new ones from a reputable source, even if they cost more you know they will be the right part, or sell the piano to someone who can repair it. You can be 99% sure that installing a pair of working DACs will get you up and running. I think it's extremely likely that you got burned with counterfeit parts.
 


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