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Cetain notes not sounding on JX-3P

Cetain notes not sounding on JX-3P

2014-01-17 by <mpigott2@...>

I went to play my JX-3P and noticed certain notes not in a row are not sounding.
Didn't have a piece of paper but they were in the lower registers.
None were in a row. It was like E not sounding then C, etc.

Put it in test mode and all oscillators are cycling through, but these same notes are not sounding. Isn't there an IC that distributes or scans the keyboard and this is at fault?

Any ideas?

Re: [vintagesynthrepair] Cetain notes not sounding on JX-3P

2014-01-17 by Daniel Forró

- Is the problem present also when you control instrument thru MIDI?

- First I would check and clean key rubber contacts, diodes in key  
assembly, connectors.

- If this will not help, it's time to check IC45 - key decoder, IC46 -  
buffer and other components between the keyboard and CPU.

Daniel Forro


On 17 Jan, 2014, at 10:30 AM, <mpigott2@...>  
<mpigott2@...> wrote:
Show quoted textHide quoted text
>
>
> I went to play my JX-3P and noticed certain notes not in a row are  
> not sounding.
> Didn't have a piece of paper but they were in the lower registers.
> None were in a row.  It was like E not sounding then C, etc.
>
> Put it in test mode and all oscillators are cycling through, but  
> these same notes are not sounding. Isn't there an IC that  
> distributes or scans the keyboard and this is at fault?
>
> Any ideas?

RE: [vintagesynthrepair] Cetain notes not sounding on JX-3P

2014-01-17 by Keith Niver

Is it like every 6 notes or 8 notes or entirely random? It could be just dirty contacts.

Keith
Show quoted textHide quoted text
From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of mpigott2@...
Sent: Thursday, January 16, 2014 8:31 PM
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Cetain notes not sounding on JX-3P





I went to play my JX-3P and noticed certain notes not in a row are not sounding.
Didn't have a piece of paper but they were in the lower registers.
None were in a row.  It was like E not sounding then C, etc.

Put it in test mode and all oscillators are cycling through, but these same notes are not sounding. Isn't there an IC that distributes or scans the keyboard and this is at fault?

Any ideas?

Re: [vintagesynthrepair] Cetain notes not sounding on JX-3P

2014-01-18 by Roger J

Keyboard scans typically use an X/Y scan much like a computer keyboard, in groups of 8 and every 8th key.  Voices repeat repeat by the number your model has available, ie a 4 voice would repeat every 4.  So count up by eights and a number will repeat in a pattern.  If any of that number start playing it is not the key scanner, but an open between one point that works and the ones that do not.
Show quoted textHide quoted text
On Saturday, January 18, 2014 2:41 AM, Keith Niver <kaniver@...> wrote:

 
>Is it like every 6 notes or 8 notes or entirely random? It could be just dirty contacts.
>Keith
> 
>From:vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of mpigott2@...
>Sent: Thursday, January 16, 2014 8:31 PM
>To: vintagesynthrepair@yahoogroups.com
>Subject: [vintagesynthrepair] Cetain notes not sounding on JX-3P
> 
> 
>I went to play my JX-3P and noticed certain notes not in a row are not sounding.
>Didn't have a piece of paper but they were in the lower registers.
>None were in a row.  It was like E not sounding then C, etc.
>
>Put it in test mode and all oscillators are cycling through, but these same notes are not sounding. Isn't there an IC that distributes or scans the keyboard and this is at fault?
>
>Any ideas?
>
>
>

Attachments

Re: [vintagesynthrepair] Cetain notes not sounding on JX-3P

2014-01-19 by Kevin Doheny

Temperature COULD be an issue, however equipment is may be subjected to temperatures colder than 2C while being shipped from one place to another in the winter. What's more of a factor is condensation which may form on anything which is brought from a cold to a warmer environment. If the temperature of the equipment is lower than the dew point of the environment, moisture can form, and may cause anything up to direct shorts in circuits when powered up. It's a very good practice to ALWAYS let equipment warm up to the temperature of the room before plugging it in, so as to allow any condensation which may have formed, to evaporate.

MARK PIGOTT wrote:
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It is the low E, then the next up C, then next up Ab, then next up E, all 8 semitones apart.

When I brought the keyboard out of the garage into the warmth, after a 20 minute warm-up, the problem
disappeared.

Right now all the notes work, can temperature be an issue? It is only 2C in the garage, I keep the gear only so it does not freeze.

do you suspect something else?

On 18-01-14, Keith Niver wrote:

Is it like every 6 notes or 8 notes or entirely random? It could be just dirty contacts.

Keith

From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of mpigott2@...
Sent: Thursday, January 16, 2014 8:31 PM
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Cetain notes not sounding on JX-3P

Re: [vintagesynthrepair] Cetain notes not sounding on JX-3P

2014-01-19 by Roger J

That is every eight key. So does this repeat all the way up or does it at some point work?
Show quoted textHide quoted text
On Saturday, January 18, 2014 3:21 PM, MARK PIGOTT <mpigott2@...> wrote:

 
>It is the low E, then the next up C, then next up Ab, then next up E, all 8 semitones apart.
>
>When I brought the keyboard out of the garage  into the warmth, after a 20 minute warm-up, the problem
>disappeared.
>
>Right now all the notes work, can temperature be an issue? It is only 2C in the garage, I keep the gear only so it does not freeze.
>
>do you suspect something else?
>
>On 18-01-14, Keith Niver  <kaniver@...> wrote:
>Is it like every 6 notes or 8 notes or entirely random? It could be just dirty contacts.
>>Keith
>> 
>>From:vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of mpigott2@...
>>Sent: Thursday, January 16, 2014 8:31 PM
>>To: vintagesynthrepair@yahoogroups.com
>>Subject: [vintagesynthrepair] Cetain notes not sounding on JX-3P
>> 
>> 
>
>
>

Re: Cetain notes not sounding on JX-3P

2014-05-13 by mpigott2@...

The problem is back, lowest E then next C up, then next Ab up then Next E.
Should I check the harness to the keys. The problem went away for 4 months, but is back. Have to use my emergency spare JX-3P...argghhhh

Re: [vintagesynthrepair] Re: Cetain notes not sounding on JX-3P

2014-05-14 by Daniel Forró

Yes, it can be a connector, or some dirtiness or oxidization inside.  
Or some of diodes on keyboard PCB are dead (usually they are used  
there) but it's not so often. Or some IC in keyboard circuit, check if  
any of them is in socket, maybe reseating can help.


Daniel Forro




On 13 May, 2014, at 9:08 AM, mpigott2@... [vintagesynthrepair]  
wrote:
Show quoted textHide quoted text
>
>
> The problem is back, lowest E then next C up, then next Ab up then  
> Next E.
> Should I check the harness to the keys.  The problem went away for 4  
> months, but is back. Have to use my emergency spare JX-3P...argghhhh

Re: [vintagesynthrepair] Re: Cetain notes not sounding on JX-3P

2014-05-15 by colin butterfield

Looks like its every eighth note and as a lot of keyboards use a diode matrix (8 x 8) then there is probably a bad connection/dry joint on one of the lines.I once bought a keyboard from a car boot with the intention of using just the keybed but when I turned it on I noticed notes were'nt playing in a regular pattern.It turned out someone had spilt something on the keyboard and it had corroded one of the tracks in the matrix.Repaired the track and lo, all notes worked so put it back together and gave it to my granddaughter. Still need to find another keyboard for a project though.
Regards Colin 
On Thursday, 15 May 2014, 1:52, "Daniel Forró dan.for@tiscali.cz [vintagesynthrepair]" <vintagesynthrepair@yahoogroups.com> wrote:

 
Yes, it can be a connector, or some dirtiness or oxidization inside. Or some of diodes on keyboard PCB are dead (usually they are used there) but it's not so often. Or some IC in keyboard circuit, check if any of them is in socket, maybe reseating can help.


Daniel Forro
Show quoted textHide quoted text
On 13 May, 2014, at 9:08 AM, mpigott2@... [vintagesynthrepair] wrote:




>
>The problem is back, lowest E then next C up, then next Ab up then Next E.
>Should I check the harness to the keys.  The problem went away for 4 months, but is back. Have to use my emergency spare JX-3P...argghhhh 
>

RE: [vintagesynthrepair] Re: Cetain notes not sounding on JX-3P

2014-05-22 by Hamblin, Scott

I just finished repairing a Korg Triton LE which had also been damaged by a drink spill. I understand certain brands of Cola are quite acidic (containing phosphoric and carbonic acid) and unless the liquid is properly cleaned from the circuit boards quickly it corrodes and eats them away.

I had a lot of success repairing the Triton board using a silver conductive pen. After complete disassembly and a through clean of the key bed PCB I used the Chemtronics silver conductor pen to redraw parts of the copper track that had been corroded through.

I used another Chemtronics product to retouch the carbon contacts under the key rubbers. Not trying to promote their products, but I have found that they both worked very well and salvaged an otherwise useless PCB.

From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com]
Sent: Friday, 16 May 2014 12:25 AM
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Re: Cetain notes not sounding on JX-3P

Looks like its every eighth note and as a lot of keyboards use a diode matrix (8 x 8) then there is probably a bad connection/dry joint on one of the lines.I once bought a keyboard from a car boot with the intention of using just the keybed but when I turned it on I noticed notes were'nt playing in a regular pattern.It turned out someone had spilt something on the keyboard and it had corroded one of the tracks in the matrix.Repaired the track and lo, all notes worked so put it back together and gave it to my granddaughter. Still need to find another keyboard for a project though.

Regards Colin

On Thursday, 15 May 2014, 1:52, "Daniel Forró dan.for@tiscali.cz [vintagesynthrepair]" <vintagesynthrepair@yahoogroups.com> wrote:

Yes, it can be a connector, or some dirtiness or oxidization inside. Or some of diodes on keyboard PCB are dead (usually they are used there) but it's not so often. Or some IC in keyboard circuit, check if any of them is in socket, maybe reseating can help.

Daniel Forro

On 13 May, 2014, at 9:08 AM, mpigott2@cogeco.ca [vintagesynthrepair] wrote:





The problem is back, lowest E then next C up, then next Ab up then Next E.
Should I check the harness to the keys. The problem went away for 4 months, but is back. Have to use my emergency spare JX-3P...argghhhh

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RE: [vintagesynthrepair] Re: Cetain notes not sounding on JX-3P

2014-08-24 by mpigott2@...

This problem is intermittent, and will go away for months at a time.Possibly moisture on the traces?

I'd like to fix it myself, but doesn't the JX-3P have plastic tape over the keys?
And do you have to remove each and every key?
That sounds like royal pain.

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