SUCCESS STORIES: Yamaha Keyboard P-95 sound problem (speakers & headphones)

Jetronic

Joined May 26, 2020
8
I finally received a few capacitors and replaced C216, C217 and C112 and it works! I replaced the first two first and try it and still no sounds so I proceed to replace C112 because it was easy to reach. After replacing C112 I realized the HP board was not connected so I connected it and everything came together. If I tested it with the HP board plugged in after just replacing C216 and C217 it might have worked. Thank you everyone.
 

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serifpersia

Joined May 19, 2020
13
I finally received a few capacitors and replaced C216, C217 and C112 and it works! I replaced the first two first and try it and still no sounds so I proceed to replace C112 because it was easy to reach. After replacing C112 I realized the HP board was not connected so I connected it and everything came together. If I tested it with the HP board plugged in after just replacing C216 and C217 it might have worked. Thank you everyone.
Well done. Thanks for letting us know. Idk when I will try to fix mine, I'm not really in a hurry, it works really well as a midi controller for now...
 

nrlopezr

Joined Apr 14, 2020
1
Hi guys, I read all the comments and followed instructions, switched out capacitors (16V 100uF) C112, C216, C217, C404 and C408 on the AM board and my piano came back to live. Thanks all!
 

serifpersia

Joined May 19, 2020
13
While I was doing some practice soldering I found this working radio board and I removed 4 100uF 16v caps. So I might try the swap tomorrow. The legs are short but I think it should be enough.20200622_201432-1.jpg20200622_201457-1.jpg
 

serifpersia

Joined May 19, 2020
13
This is a good idea. Reuse.
I just opened the the case and I found that my c216 and c217 are 25V 100uf. I checked other small caps around and they were 16v but the c216 and c217 are 25V. Did yours have 16V? I think that someone replaced those caps with 25V instead of 16V
 

Jetronic

Joined May 26, 2020
8
Yes, I had 16V for C216 and C217. All the five caps mentioned in this thread for my P-95 has the same spec and blue colour with black stripes for negative polarity. My replacement caps from Amazon were black with same specs.
 

serifpersia

Joined May 19, 2020
13
Here is the situation. I removed c216, c217 and I tried it without the cable that connects the hp board. There was no relay click but there was no sound as well. So I reconnected the hp board, this time the same relay click after 3 seconds is being heard even when I desoldered those two caps. I replaced them with 16V 100uf but sadly still no sound just the relay click. I will replace c112 and see if that changes something.
 
Alright, after replacing a ton of components on the AM board, I finally have sound. Certain ranges of keys aren’t playing, but the lowest and highest keys do emit sound. Advice?
 

stragulus

Joined Feb 9, 2016
12
Managed to fix mine as well. Replaced C216 and C217 blindly since it would be good out of precaution anyway. Still no sound. So I used a DIY audio tracer (really just a wire hooked up to a line-in on a portable amp with a 10uF capacitor in series). Audio made it all the way to the power amp on the AM board, but no audio was present on its outputs. It had 12V, so I just checked the datasheet of the amp (LA4625). Turns out C112 connected from GND to pin 2 was shorted, inhibiting the function of the amp. With that replaced, it worked!

That was a fun chase, but the excellent service manual of the P-85 made light work of it.
 

dl324

Joined Mar 30, 2015
13,841
So I used a DIY audio tracer (really just a wire hooked up to a line-in on a portable amp with a 10uF capacitor in series). Audio made it all the way to the power amp on the AM board, but no audio was present on its outputs. It had 12V, so I just checked the datasheet of the amp (LA4625). Turns out C112 connected from GND to pin 2 was shorted, inhibiting the function of the amp. With that replaced, it worked!
At last. Someone who actually did some troubleshooting instead of just guessing. Congrats!

EDIT: How much did the DIY audio tracer cost you? I recently bought a toy scope (DSO 138); not bad for $20 (assembled and with a case - case needs to be assembled). It would be fine for audio frequencies. There's a hack on github to make it dual trace.
 
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stragulus

Joined Feb 9, 2016
12
At last. Someone who actually did some troubleshooting instead of just guessing. Congrats!

EDIT: How much did the DIY audio tracer cost you? I recently bought a toy scope (DSO 138); not bad for $20 (assembled and with a case - case needs to be assembled). It would be fine for audio frequencies. There's a hack on github to make it dual trace.
This is a 'dumb' tracer, e.g. it does not inject any signals. It's literally just a wire with a series capacitor, where you touch the lead to the components. The other wire is connected to the speaker negative terminal. Simply hooked up to an aux input of a small portable boombox. Press the 'demo song' button and listen to the audio output through the boombox speakers.

As simple as it is, it's proven very helpful for debugging any kind of audio system.
 

JoeJester

Joined Apr 26, 2005
4,390
Alright, after replacing a ton of components on the AM board, I finally have sound. Certain ranges of keys aren’t playing, but the lowest and highest keys do emit sound. Advice?
Look at the schematic and see how the keys are "grouped". Then test EVERY key from left to right ... note which ones are working and NOT working ....


What test equipment do you have to solve this problem?
 

blerpa

Joined Aug 31, 2020
2
had the same problem, no sound.

Checked all elco's on AM board. one was faulty, 33 uF 16V. Replaced with 33uf/25V.

It is a piano again! this thread helps a lot (thanks to multimeter to!)
 

MrChips

Joined Oct 2, 2009
25,040
had the same problem, no sound.

Checked all elco's on AM board. one was faulty, 33 uF 16V. Replaced with 33uf/25V.

It is a piano again! this thread helps a lot (thanks to multimeter to!)
In order to help others with similar issues please specify which capacitor you replaced, C216 for example, and the model number of your keyboard, Yamaha P-95 for example.

Glad you fixed the problem.
 

blerpa

Joined Aug 31, 2020
2
Sorry, it is a yamaha P-95. Closed it so I can not see which one it was.
How we checked is testing resistance of all elco's with a multimeter in resistance mode (lowest range). All had resistance but one (multimeter says "beep" and reads 0). I replaced it with same capacitance but higher voltage rating. Hope it stays longer then!
 
Thanks for all the instructions on this message board!
My problem: After two years of non-use, there's no sound from speakers nor headphones on my Yamaha P95b.
Solution: Switched out capacitors (16V 100uF) C112, C216, C217, C404 and C408 on the AM board. I didn't diagnose to check if they were faulty or not.
I had the same problem, did exactly the same as above, and my keyboard (Yamaha P-95) works perfectly now.
Many thanks everyone for sharing this brilliant solution (and its various minor variants)!
 

MisterBill2

Joined Jan 23, 2018
10,572
Right now I am wondering about the brand of those capacitors that were replaced. At one time it was standard to replace Rubycon brand capacitors in Sony and Superscope equipment any time it needed service. So it would be interesting to know what brand had a quality problem, or possibly still has a quality problem.
 
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