Hi .I have a Technics KN1000 that was given to me.It takes about 5 minutes for the keyboard to produce the correct sounds. From then onwards the keyboard will sound correctly even if I leave it on for a day . while it is "warming" up there is audio but only static noise like an off station radio. I have replaced a couple capacitors whose ESR value was a bit low. This has not helped. while open I have run a small heat gun over all caps and IC's and diodes but it does not speed up the working time for the keyboard to output proper PWM sounds. If anyone could make a suggestion I will appreciate and try. Thankyou in advance
Technics Kn1000 fault
- Thread starter Haddon
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Cosmos
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Hi,
I would first try checking all the voltages coming out of the power supply. Also possibly connect a scope and monitor them.
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Personally.... I'd dump it!
It's so old as to be pretty well worthless, it didn't cost you anything, and apart from the obvious possible fire risk, I wouldn't waste any more time on it. Life's too short.
It's so old as to be pretty well worthless, it didn't cost you anything, and apart from the obvious possible fire risk, I wouldn't waste any more time on it. Life's too short.
Cosmos
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It depends, because sometimes it could be something of sentimental value. Also, in my opinion we are creating too much waist. Personally I like vintage keyboards and am willing to accept them and restore them
Thank you for the help. I will use the scope to monitor "noise"on the DC. I feel hopeful. The keyboard is sentiment right now and not having funds right now to do anything major in purchases. I'm on pension and have more time than cash.Then there is the challenge to get it right and not give up for myself.If I did give it to someone in need I would like to give them a working unit.Thank you for responding "Members".
Cosmos
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Rather then using a heat gun (which, if you're not careful, could make more damage somewhere else) I would let the keyboard switched-on for it to warm up until proper sound comes out, then use a can of freezer and spray any suspect ICs, like perhaps the DAC (digital to analog converter) IC. Start first by identifying it.
The honour is in reviving the keyboard not dump it
Good luck
Cosmos
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Did you connect headphones or take output from the line-outs to identify if fault is in amplifier or before it?
If fault is before amplifier I would spray freezer on the DAC IC19 and there is a set of ICs starting from 4 to 8 that are filters and noise reduction. But first you have to make sure that the amplifier is alright. After that, it also makes sense to monitor the output directly from the DAC chip but be careful not to short any pins! I used to use a signal injector set on monitor mode to do this.
I'm assuming you have the service manual to access the schematic.
Once again
Good luck
oh dear I made a solder bridge while changing all the caps. Motherboard dead now even after changind the 10 Ohm supply restistors on the plus and Minus suplies.So ive decided to scrap the unit. Thankyou
Ouch... oh well, there are a ton of other arrangers out there now (and Technics' keyboard division *did* go under in 2002, so parts would've been impossible to find at this point)