Hi, I'm a technician as hobby, I repaired several yamaha keyboards in the keyboard unit (some key doesn't sound or sound too much, etc.).
I'm in trouble with a never seen case regarding a Yamaha tyros 2 61 keys. The problem is that all the couple the D# - A keys sound only the first time I press them. The second time I press them they don't sound anymore. The first time, they sound with a sustain too. The D# and A are on the same wires in the matrix scan as you can see from the attached schematics. I found a video in which the problem is as similar as in my case.
https://www.youtube.com/watch?v=EKascHbPazA&t=707s
(from 4:05 couple of keys F#-C)
In the past I repaired several keyboards with a persistent couple of keys on the same scan wire (eg D#-A or C#-G and so on) that didn't sound. The fault was persistent, they didn't sound the first time I pressed them. In that case the solution was to check continuity on the circuit scan, from the flat connectors to the single PCB traces related to that keys.
Now the things are a bit different, there is no true interruption in the circuit (the first time they sound) because the first time they sound. Anyway I checked the entire D#-A circuit up to the matrix scan board connector and all seem OK. I noticed a lot of oxidation on some soldered connector pins, but it seems to be only an aesthetic issue because electrically speaking all seems OK.
The only think I understood is that connecting only the MKH-D part of the keyboard the problem persists. The EMKS board (the matrix scanner) is directly connected to the MKH-D board. The MKH-D board is connected to the MK61-L by means of a FLAT cable, but this is not the problem as I said before.
Someone had a similar problem and solved it?
I have not re-soldered yet the pin cable on the PCB as in the video because all seems ok electrically (I checked the continuity from the connector pin to the microcontroller’s pin too) and to avoid to do a mess due to the very short distance pin.
Thanks a lot.
I'm in trouble with a never seen case regarding a Yamaha tyros 2 61 keys. The problem is that all the couple the D# - A keys sound only the first time I press them. The second time I press them they don't sound anymore. The first time, they sound with a sustain too. The D# and A are on the same wires in the matrix scan as you can see from the attached schematics. I found a video in which the problem is as similar as in my case.
https://www.youtube.com/watch?v=EKascHbPazA&t=707s
(from 4:05 couple of keys F#-C)
In the past I repaired several keyboards with a persistent couple of keys on the same scan wire (eg D#-A or C#-G and so on) that didn't sound. The fault was persistent, they didn't sound the first time I pressed them. In that case the solution was to check continuity on the circuit scan, from the flat connectors to the single PCB traces related to that keys.
Now the things are a bit different, there is no true interruption in the circuit (the first time they sound) because the first time they sound. Anyway I checked the entire D#-A circuit up to the matrix scan board connector and all seem OK. I noticed a lot of oxidation on some soldered connector pins, but it seems to be only an aesthetic issue because electrically speaking all seems OK.
The only think I understood is that connecting only the MKH-D part of the keyboard the problem persists. The EMKS board (the matrix scanner) is directly connected to the MKH-D board. The MKH-D board is connected to the MK61-L by means of a FLAT cable, but this is not the problem as I said before.
Someone had a similar problem and solved it?
I have not re-soldered yet the pin cable on the PCB as in the video because all seems ok electrically (I checked the continuity from the connector pin to the microcontroller’s pin too) and to avoid to do a mess due to the very short distance pin.
Thanks a lot.
what did we say about hoarding too much stuff and depriving others of them?! *cough* socialism *cough* lol! 
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