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#67141 - 06/07/08 04:46 PM Re: prolongued blockcord-playing KN7000
Audrey Turner Offline
Senior Member

Registered: 03/19/02
Posts: 1080
Loc: Cambridge, Cambs, England
Hello Folks!

Just to add more mystery to the heating up of the KN7, you may recall when Technics ceased trading I bought a second KN7 as a "standby". This was hardly used by the last owner and is in immaculate condition whereas the keys are beginning to show 'wear and tear' on my own KN7. I took this second keyboard to a 'WW2 Reunion' gig last night.
I started playing at 6.30pm and with just a 15 minute break, finished at 11 pm. The keyboard was on all the time and I noticed on packing up that it wasn't so much as lukewarm. How strange is that?

Another thing, they both show the same version, yet the latest KN7 sound is more
'mellow' than the other and yes! I have investigated as to whether it is setup differently when in the Factory Mode and it isn't. One of the mysteries of life I guess.

Audrey

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#67142 - 06/07/08 04:59 PM Re: prolongued blockcord-playing KN7000
kitkat Offline
Member

Registered: 05/15/08
Posts: 235
Loc: United States
Where Bill states the warmth is, is exactly where slight warmth is on my KN7000. At times, I have my keyboard on for 6 or seven hours with very little warmth. I am in the U.S. and the voltage is 110. Could it be that many of you in the U.K. and Europe with different voltage be the reason for this "hot" problem? I could be wrong but I think most of Europe is 220 V. Is this correct?

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#67143 - 06/08/08 04:05 AM Re: prolongued blockcord-playing KN7000
Fran D Offline
Member

Registered: 01/26/02
Posts: 918
Loc: Aiken, SC, USA
I think Rog has the answer. The more items stored in memory causes the search engine to over heat while searching.

Fran in SC

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#67144 - 06/08/08 11:59 AM Re: prolongued blockcord-playing KN7000
Audrey Turner Offline
Senior Member

Registered: 03/19/02
Posts: 1080
Loc: Cambridge, Cambs, England
I think you could be right about the electricity differenc Kit Kat. Over here we are 240v, but it doesn't explain the difference between the two keyboards. They are loaded with exactly the same amount of data on each so I don't think it's anything to do with memory. It could however be due to them being manufactured at different times. Still! as long they both respond/play correctly I'll be happy.

Audrey

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#67145 - 06/08/08 02:58 PM Re: prolongued blockcord-playing KN7000
Bernie9 Offline
Senior Member

Registered: 09/21/02
Posts: 3820
Loc: Port Charlotte,FL,USA
Fran
It sounds like you and Rog don't believe the block chords is causing the heat up. I'd bet you don't believe in the tooth fairy,either.
_________________________
pa4X 76 ,Audya 76,Yamaha S970 , vArranger, Hammond SK1, Centerpoint Space Station

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#67146 - 06/08/08 07:32 PM Re: prolongued blockcord-playing KN7000
kitkat Offline
Member

Registered: 05/15/08
Posts: 235
Loc: United States
One thing that no one has thought of is that the company may have used various power supplies from companies - a very common practice. If so, it is possible that some could overheat more than others. I do think that any unit that has a lot of heat will likely have a shorter life than units that don't generate as much heat.

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#67147 - 06/09/08 03:45 AM Re: prolongued blockcord-playing KN7000
fredyfr Offline
Member

Registered: 12/15/07
Posts: 80
Loc: altea, spain
that was a laugh with Bernies' "tooth fairy".
Ok, but we still don't know if there is or not a fan inside which could explain plenty.
In UK current is apparently 240 and on the continent 220 volts. Not being an electrician I would not venture to say that there might be a reason for this issue of warming-up.

------------------

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#67148 - 06/09/08 12:46 PM Re: prolongued blockcord-playing KN7000
Bill Norrie Offline
Senior Member

Registered: 01/16/02
Posts: 2275
Loc: Richmond,North Yorkshire, UK
As Bob H. and I said above, there does not appear to be a fan listed within the parts list in the Service manual, but there are references to 'FAN BAGS' ???
I'm fairly certain that there was a fan in the KN6000 so it seems strange that one should not be included in the KN7000. I suppose the only certain way to find out is to remove the top cover, but I'm not inclined to do so at present

Whether the supply voltage is 220/240 or 110/115 should not make any difference to the heat generated by the Power Supply printed circuit board, mentioned in my previous post. The supply voltage will be dropped down, by the internal Mains Transformer, to the same feed voltage to the Power Supply PCB - probably around '18v' AC or so.
So for example, depending on the model, the Transformer will reduce the 240/220 to say 18v - or in the case of USA - 110/115 to '18v' AC.
In fact, there are three different transformers listed : one for USA/Canada, one for the Far East (With a voltage selector switch) and one for the rest of the world, including UK/Europe. So, each transformer would deliver the same Output voltage to the Rectifier and subsequent Voltage Regulators. This allows a common Power Supply PCB to be used in all models, irrespective of Mains Supply.

So basically, the transformer takes care of the differences in Supply Voltage and no significant extra heating should be generated, as a result of the keyboard operating at a higher voltage - unless, of course, someone decides to operate a 110/115v model at 220/240v
_________________________
Willum

After silence, that which comes nearest to expressing the inexpressible is Music.
Aldous Huxley

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#67149 - 06/10/08 12:10 AM Re: prolongued blockcord-playing KN7000
Audrey Turner Offline
Senior Member

Registered: 03/19/02
Posts: 1080
Loc: Cambridge, Cambs, England
Here's another mystery for you all.

The KN7 belonging to one of our keyboard members not only warms up similar to mine, but also makes a noise (which he calls "spitting") for a fraction of a second.
It only does this now and again but when it does it is enough to 'startle' the musician who's playing at the time.

Could this be an electrical short circuit do you think Bill? If so, what's the cure?

Audrey

[This message has been edited by Audrey Turner (edited 06-10-2008).]

[This message has been edited by Audrey Turner (edited 06-10-2008).]

[This message has been edited by Audrey Turner (edited 06-10-2008).]

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#67150 - 06/10/08 03:10 AM Re: prolongued blockcord-playing KN7000
Fran D Offline
Member

Registered: 01/26/02
Posts: 918
Loc: Aiken, SC, USA
My 7000 also got very warm while playing. When the sound quit, I removed the cover to check for fuses and I did not see any fan in the power supply board area only heat sinks. I do not remember the part name but it's cost was only about $20 and I was fortunate to find a repair man that was not just a board changer, which is prevalent today.

Fran in SC

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