Hi, first time poster.

I'm writing on behalf of my Grandfather, who's KN-5000 has started to produced a horrible electronic noise from the left speaker. Sometimes when the keyboard is restarted the sound will work fine again, then after a number of seconds crackles and pops can be heard before getting quickly worse. I've opened the top up and given all the components a good clean, as well as plugging into another socket, but to no luck. Moving the volume slider bar at all seems to escalate the problem too.

Any insights would be greatly appreciated!

You state that you have given the components a good cleaning, did you use an electronic cleaner spray? If not, try using some in the volume slot and go up and down on the slider several times. It sounds like just a dirty connection.

Hi, thanks for your suggestion.

I've finally managed to try that, but unfortunately it didn't work at all, even after several attempts.

The noise is a really loud intrusive crackle, so I'm wondering if it's a more severe problem? Also, it appears the noise occurs only in the left speaker, while the right doesn't seem to work at all now. It's odd because as far as I could tell everything was functioning fine before.

Just wondered which country you are in?

England.

Years ago I had a KN5000 with a similar problem, I ended up putting a jack in the headphone and used external speakers.

Well I've had a bit of progress. After startup the speakers will crackle, but after a short while it'll pass and everything sounds as it should again... No sign of any problems. However if I turn the keyboard off and on again, it'll do the same thing. I've sprayed the volume switch again with electronic cleaner spray, and will leave it alone for longer. Hopefully it'll clear up for good. I'm getting closer!

It can require two or three sprayings. Did you go up and down several times on the volume switch when you used the electronic cleaner? Also, don't turn the keyboard on until it is fully dry.

Mark

Yeah I've gone up and down many times with the slider, and sprayed it a few times. Unfortunately this morning it was back to it's crackling best. I feel I'm getting closer, as yesterday once it cleared it stayed clear. There's something to turning it off and on again that's causing problems.

Problem can be caused by the electronisch or by defective speaker. To check this you can switch off the speakers by using a headphone. If the problem is still there the problem is somewhere in the electronic circuit.

After checking the service manual I found out that my previous post is not correct.
The headphones and speakers have separate amplifiers. Also woofer and both L+R speakers (midrange and tweeter) have separate power amplifiers. You say that the crackle is only in the left speaker (mid range and tweeter). If it is not in the woofer then you will probably not hear it In the headphone either, also not in the line output. Woofer and other speakers partly use same preamplifier (equalizer). This means that the source of he crackle probably will be in the power amplifier of the left speakers or in the speakers itself. You should check the presence of the crackle in all available outputs (sub-out, line out, headphone, woofer, midrange sp and tweeter) to find the source of the crackle. Good luck!
Bert

Please notice that my previous posts are related to the KN7. I do not have the service manual of KN5 but I assume that the basics are the same.

Hi, your problem is with a KN5000, the service manual in on this web site go to Nigel's archive and then KN5000 the manual is there but if you have been using the KN7000 manual the KN7 is very different in all ways as the amp system is all digital right up to the last stage of amplification as the keyboard is able to transmit and receive via USB on the audio side.for your keyboard use the correct manual as all KN series keyboards have major differences between each other.
Best regards John.