Yamaha MOXF8 keyboard, one note plays too loud!

[David Farber]

This Yamaha MOXF8 keyboard has one note that plays too loud when more than
the slightest of pushes is given. I moved the keypad underneath to a
diffenerent octave and the problem followed the keypad. In other words, the
note that was too loud, switched to the same note but in a different octave.
I can't see anything visually wrong with the keypad contacts. There are two
pc contacts per note. One rubber keypad contact opposite the pc contact
extends just a hair more than its adjacent rubber keypad contact. How does
this translate into detecting how loud to play a note and how do you think
this relates to the note that is too loud?

Thanks for your reply.
--
David Farber
Los Osos, CA

 

[Clifford Heath]

On 16/04/17 01:23, David Farber wrote:

This Yamaha MOXF8 keyboard has one note that plays too loud when more than
the slightest of pushes is given. I moved the keypad underneath to a
diffenerent octave and the problem followed the keypad. In other words, the
note that was too loud, switched to the same note but in a different octave.
I can't see anything visually wrong with the keypad contacts. There are two
pc contacts per note. One rubber keypad contact opposite the pc contact
extends just a hair more than its adjacent rubber keypad contact. How does
this translate into detecting how loud to play a note and how do you think
this relates to the note that is too loud?

It's a dual-contact pad. One of each pair should contact before the other.

This behaviour is what happens when the early contact fails, and the
late one does not. The controller sees nothing, followed by the late
contact, so it assumes a high-velocity key-stroke and plays full volume.

Fix or replace the early contact.

 

[Pat]

On Sat, 15 Apr 2017 08:23:53 -0700, "David Farber"
<farberbear.unspam@aol.com> wrote:

This Yamaha MOXF8 keyboard has one note that plays too loud when more than
the slightest of pushes is given. I moved the keypad underneath to a
diffenerent octave and the problem followed the keypad. In other words, the
note that was too loud, switched to the same note but in a different octave.
I can't see anything visually wrong with the keypad contacts. There are two
pc contacts per note. One rubber keypad contact opposite the pc contact
extends just a hair more than its adjacent rubber keypad contact. How does
this translate into detecting how loud to play a note and how do you think
this relates to the note that is too loud?

Thanks for your reply.

Total guess on my part, but it probably detects how fast you press the
key (rather than how hard you press). If the two contacts are made
simultaniously, it thinks you want a loud note. (Or maybe, one
contact is stuck on? Or, an input port on an I/O chip is bad?) Good
luck.

 

[N_Cook]

On 15/04/2017 16:23, David Farber wrote:

This Yamaha MOXF8 keyboard has one note that plays too loud when more than
the slightest of pushes is given. I moved the keypad underneath to a
diffenerent octave and the problem followed the keypad. In other words, the
note that was too loud, switched to the same note but in a different octave.
I can't see anything visually wrong with the keypad contacts. There are two
pc contacts per note. One rubber keypad contact opposite the pc contact
extends just a hair more than its adjacent rubber keypad contact. How does
this translate into detecting how loud to play a note and how do you think
this relates to the note that is too loud?

Thanks for your reply.

Usually 2-stage contacts, and timing the difference.
Can you swap a pair of the silicone contact pad strips over , to another
part of the keyboard to see if the problem moves with it.
Check pull-up/down Rs between adjascent keys?
Can you easily swap a multiplex line over with another?

 

[Jocelyn Goodey]

On Sat, 15 Apr 2017 17:58:48 +0100, N_Cook <diverse@tcp.co.uk> wrote:

On 15/04/2017 16:23, David Farber wrote:
This Yamaha MOXF8 keyboard has one note that plays too loud when more
than
the slightest of pushes is given. I moved the keypad underneath to a
diffenerent octave and the problem followed the keypad. In other words,
the
note that was too loud, switched to the same note but in a different
octave.
I can't see anything visually wrong with the keypad contacts. There are
two
pc contacts per note. One rubber keypad contact opposite the pc contact
extends just a hair more than its adjacent rubber keypad contact. How
does
this translate into detecting how loud to play a note and how do you
think
this relates to the note that is too loud?

Thanks for your reply.


Usually 2-stage contacts, and timing the difference.
Can you swap a pair of the silicone contact pad strips over , to another
part of the keyboard to see if the problem moves with it.
Check pull-up/down Rs between adjascent keys?
Can you easily swap a multiplex line over with another?

Try wiping the carbonised contact pads with an cotton bud soaked in IPA.
If that fails try a gentle rub of the black pips with a fine emery board &
wipe with IPA again.


Regards Joss

Tetigisti acu (Titus Maccius Plautus 254-184BC)

 

[David Farber]

Clifford Heath wrote:

On 16/04/17 01:23, David Farber wrote:
This Yamaha MOXF8 keyboard has one note that plays too loud when
more than the slightest of pushes is given. I moved the keypad
underneath to a diffenerent octave and the problem followed the
keypad. In other words, the note that was too loud, switched to the
same note but in a different octave. I can't see anything visually
wrong with the keypad contacts. There are two pc contacts per note.
One rubber keypad contact opposite the pc contact extends just a
hair more than its adjacent rubber keypad contact. How does this
translate into detecting how loud to play a note and how do you
think this relates to the note that is too loud?

It's a dual-contact pad. One of each pair should contact before the
other.
This behaviour is what happens when the early contact fails, and the
late one does not. The controller sees nothing, followed by the late
contact, so it assumes a high-velocity key-stroke and plays full
volume.
Fix or replace the early contact.

Hi Clifford,

I will replace the pad assembly. Thanks for the great explanation.
--
David Farber
Los Osos, CA

 

[N_Cook]

On 14/04/2017 10:04, Clifford Heath wrote:

On 16/04/17 01:23, David Farber wrote:
This Yamaha MOXF8 keyboard has one note that plays too loud when more
than
the slightest of pushes is given. I moved the keypad underneath to a
diffenerent octave and the problem followed the keypad. In other
words, the
note that was too loud, switched to the same note but in a different
octave.
I can't see anything visually wrong with the keypad contacts. There
are two
pc contacts per note. One rubber keypad contact opposite the pc contact
extends just a hair more than its adjacent rubber keypad contact. How
does
this translate into detecting how loud to play a note and how do you
think
this relates to the note that is too loud?

It's a dual-contact pad. One of each pair should contact before the other.

This behaviour is what happens when the early contact fails, and the
late one does not. The controller sees nothing, followed by the late
contact, so it assumes a high-velocity key-stroke and plays full volume.

Fix or replace the early contact.

Isn't that interpretted as a non-key press, a dead note, second contact
only. I seem to remember simulating that, with placing a piece of paper
under the first contact.

 

[Clifford Heath]

On 16/04/17 18:03, N_Cook wrote:

On 14/04/2017 10:04, Clifford Heath wrote:
On 16/04/17 01:23, David Farber wrote:
This Yamaha MOXF8 keyboard has one note that plays too loud when more
than
the slightest of pushes is given. I moved the keypad underneath to a
diffenerent octave and the problem followed the keypad. In other
words, the
note that was too loud, switched to the same note but in a different
octave.
I can't see anything visually wrong with the keypad contacts. There
are two
pc contacts per note. One rubber keypad contact opposite the pc contact
extends just a hair more than its adjacent rubber keypad contact. How
does
this translate into detecting how loud to play a note and how do you
think
this relates to the note that is too loud?

It's a dual-contact pad. One of each pair should contact before the
other.

This behaviour is what happens when the early contact fails, and the
late one does not. The controller sees nothing, followed by the late
contact, so it assumes a high-velocity key-stroke and plays full volume.

Fix or replace the early contact.


Isn't that interpretted as a non-key press, a dead note, second contact
only. I seem to remember simulating that, with placing a piece of paper
under the first contact.

You might have had them switched around.

It's not possible to trigger on the first contact,
because you don't yet know how fast the key-press is.
So instead you trigger on 2nd contact - if that never
happens there should be no trigger.

Clifford Heath.