Yamaha CN-70

[Guest]

Hi, Just finished a Yamaha CN-70 which had been lying unused for almost 20 years. The owner complained that there was no volume.</p>

I assumed the main capacitors had failed because the organ had never been powered up in the interval.</p>

Turned out there were 3 separate faults:</p>

1. An opamp 4558 beside the main volume control was dead - replaced, full volume.</p>

2. Swell pedal intermittent - wires corroded so leads trimmed and extended using enamelled wire - pedal works.</p>

3. All G keys dead - keyboard disassembled - part of the track dissolved, probably fruit juice or similar - PCB cleaned and a jumper wire fitted across the broken track - all keys working.</p>

I took some photos of the keyboard assembly and repair - if anyone is interested I can put them on the forum. I checked the net before beginning this job and there is very little info on this type of fault or its repair so perhaps the info might be of use.</p>

All the best,</p>

HughDoc</p>

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[Guest]

Hi, Just finished a Yamaha CN-70 which had been lying unused for almost 20 years. The owner complained that there was no volume.</p>

</p>

</p>

Hi HughDoc,

Your post is quite old but thought you may still be around.

I have an old Yamaha CN-70 that was working a moment ago but just now the keyboard keys have stopped working. The rhythm and tempo keys are work but not the keyboard. For an amateur (yet my husband is quite handy and usually manages to fix most things) are there some basic checks we can make on where the problem could be?

Thanks
Carmen

[Guest]

Hey Carmen
I have the exact same problem with my CN70. Also when I turn it on it make a high pitch noise and the tone select bottons make a cracking sound. Similar? Did you manage to figure what was wrong with yours?

[Guest]

Little volumen in the not ABC side

Dear sirs, i´ve just bought CN-70, i´ve bought it knowing the not ABC keys sound low even at full volume, in the other side, ABC key sound full volume.
Does this look familiar to someone? how do you resolved it?

Kind regards, from Argentina, Emiliano!

Hi, Just finished a Yamaha CN-70 which had been lying unused for almost 20 years. The owner complained that there was no volume.

I assumed the main capacitors had failed because the organ had never been powered up in the interval.

Turned out there were 3 separate faults:

1. An opamp 4558 beside the main volume control was dead - replaced, full volume.

2. Swell pedal intermittent - wires corroded so leads trimmed and extended using enamelled wire - pedal works.

3. All G keys dead - keyboard disassembled - part of the track dissolved, probably fruit juice or similar - PCB cleaned and a jumper wire fitted across the broken track - all keys working.

I took some photos of the keyboard assembly and repair - if anyone is interested I can put them on the forum. I checked the net before beginning this job and there is very little info on this type of fault or its repair so perhaps the info might be of use.

All the best,

HughDoc

[Kurzweil]

The OP dealt with his dead G notes by repairing a circuit board under the keys. I would start there. These probably open up like other Japanese organs with screws under the desk that let the upper manual and controls tilt up.