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RE:KN7000 SOUND OUTPUT FAILURE

buckiec

buckiec
Australia

Total Posts: 13
Joined: January 13, 2015

Greetings from Western Australia.


I was connecting my Laptop( XP as the OS) to the KN7000 yesterday.

The connection was a complete success.All Drivers, and Technics Software (Song Manager, SD Jukebox and Recorder) installed.

I was testing the sound output from PC to KN7000 by playing MP3 files through the KNs onboard Amp,when all of a sudden the sound went dead. Absolutely nothing was heard,even when I tried to play the KN normally.I performaed the necessary diagnostcs/troubleshooting procedures without success

CURRENT STATUS:

ALL other functions work fine on the KN but no sound emanates from Sound Generator/Amp.


Would really appreciate any help/suggestions you can offer

Regards

Christopher BUCKIE

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Posted on February 5, 2018 at 5:07 AM
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5 Replies

admin

admin
United Kingdom

Total Posts: 1067
Joined: February 2, 2014

Re: RE:KN7000 SOUND OUTPUT FAILURE

Sorry to hear that!

Is it very hot there right now?

Can you hear anything through headphones?

Posted on February 5, 2018 at 5:38 AM

buckiec

buckiec
Australia

Total Posts: 13
Joined: January 13, 2015

Re: RE:KN7000 SOUND OUTPUT FAILURE

Thanks Mike for your prompt response.

1. Very hot these days although KN7000 project is in air conditioned environment. I did notice that the cabinet became quite hot (Normal for KN7000) during the upgrade.My 7000 was purchased in USA quite some time ago. Of course the unit uses only 120 volts so I have a "Step down" transformer to comply with Australian standards (240 Volts) This unit,as with the KN7000 always heats up quite considerably under normal operation.I have been using this configuration for quite some time now and have never had any problems.

2. No sound through Headphones or via line our to external amp

I am fairly sure that KN7000 circuitry comes with some sort of safety cut out mechanisms (fuses etc) when overheating becomes an issue.Although every other function on the 7000 still works perfectly. Maybe Dave Tutt may know . In the meantime I will be performing "Functionality" tests as per KN7000 Service Manual

Perhaps the worst case scenario would be that the Sound Board and Amp Board have burnt out.

Posted on February 5, 2018 at 6:16 AM

buckiec

buckiec
Australia

Total Posts: 13
Joined: January 13, 2015

Re: RE:KN7000 SOUND OUTPUT FAILURE

Hi Mike,

I have investigated this problem further: Here are my findings:

1. I tried the factory reset in the first instance.....no difference

2. Tried the KN7000 full system Diagnostic as per the Service Manual....all
appears ok (including Sound Module etc)

3. Tried the insert/withdrawal of the Headphone plug. Apparently there is a "cut off switch" which can become dirty thereby disabling the internal speakers.On completing this procedure although no full
sound was heard through the on board speakers,a faint "hissing" sound was
heard in the headphones.Sounded like the amplifier was on but no sound was
coming out of it.Furthermore, when I placed the Keyboard in "Demo" mode,
very faint musical sounds emanated from both headphones.

I have a feeling that there is a sound card hardware issue here.If I can identify which component has failed I should be able to purchase a replacement.

Cheers

Chris

Posted on February 7, 2018 at 9:20 AM

davetutt

davetutt
United Kingdom

Total Posts: 166
Joined: January 12, 2015

Re: RE:KN7000 SOUND OUTPUT FAILURE

The 7000 is prone to faults in the power supply and specifically the 15 volt regulators. When these go you get no sound. Even if its just one of them. They are protected by fast acting wire ended fuses which will need to be replaced too. You will also have to swap out all the associated electrolytic caps. I have done lots of these some of which have been shipped to hot countries but it is important that it gets some modifications else it will just fail again. You need a decent heatsink for all the power supply devices which can be fitted over the top of the output connectors on the rear panel. I have posted lots about this on here so you might want to have a look around!

Dave

Posted on February 18, 2018 at 9:44 AM

buckiec

buckiec
Australia

Total Posts: 13
Joined: January 13, 2015

Re: RE:KN7000 SOUND OUTPUT FAILURE

Thanks heaps for the reply Dave....much appreciated.

This has given me something to work to.The problem is not as bad as I first thought.

Regards

Chris

Posted on March 4, 2018 at 5:04 PM