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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Yamaha MOXF8 keyboard, one note plays too loud!
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. |
#2
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Yamaha MOXF8 keyboard, one note plays too loud!
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 |
#3
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Yamaha MOXF8 keyboard, one note plays too loud!
On Sat, 15 Apr 2017 08:23:53 -0700, "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. 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. |
#4
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Yamaha MOXF8 keyboard, one note plays too loud!
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? |
#5
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Yamaha MOXF8 keyboard, one note plays too loud!
On Sat, 15 Apr 2017 17:58:48 +0100, N_Cook 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) |
#6
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Yamaha MOXF8 keyboard, one note plays too loud!
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 |
#7
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Yamaha MOXF8 keyboard, one note plays too loud!
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. |
#8
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Yamaha MOXF8 keyboard, one note plays too loud!
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. |
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