KORG M1 - No sound / Low battery indication. SOLVED!

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Yekuku
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Re: KORG M1 - No sound / Low battery indication. SOLVED!

Post by Yekuku » Wed Nov 21, 2018 7:57 am

Did you visually check all resistors as well or test them all?
Does measuring resistance change with polarity?
If my memory serves me right, I did not check for any faulty resistors, I inspected the board visually and I noticed that a discolored resistor had gone up in value, by replacing it the problem was gone.
It does not matter where you put the multimeter probes when measuring resistance, readings should not change.
good luck !
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Mooger5
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Re: KORG M1 - No sound / Low battery indication

Post by Mooger5 » Thu Nov 22, 2018 7:35 am

Yekuku wrote: There is one problem though...
I installed factory sounds and i am having a slightly distorted output.
Most sounds play ok, but many loud patches distort like there is an internal clipping going on, that happens even when I lower the volume slider. this problem is more obvious when playing chords, as the velocities of many notes are added, sound gets easily clipped internally.
Yekuku wrote:Well, my M1 is alive and kicking again:)
After replacing C23 ( 220uf @ 25v) in the power supply board (KLM-1269) I noticed a discolored resistor (R79 @ 10 Ohm in the DAC board (KLM-1261), which was causing the distortion.
After replacing the resistor the output is crystal clear again :D
Thanks for this. Not the same engine but my newly acquired Kawai K4 has the same symptoms you´ve described.
Herrare umanum est.

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Yekuku
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Re: KORG M1 - No sound / Low battery indication. SOLVED!

Post by Yekuku » Thu Nov 22, 2018 11:32 am

Hi Mooger5 , I am glad that the info that I have posted was useful to you.
Resistors rarely go up in value value unless they are overpowered , usually it is sth else that triggers this behavior.
Did you find the culprit that is causing the distorted output on the K4?
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Re: KORG M1 - No sound / Low battery indication. SOLVED!

Post by Mooger5 » Thu Nov 22, 2018 12:32 pm

Hi. Not yet, wasn´t sure it was a fault or just part of the "character". I´ll have a look iniside later. It´s probably being underpowered and the PSU is unusual (+9/+5/unknown), so I better study the schematics thoroughly before attempting anything else.
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Yekuku
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Re: KORG M1 - No sound / Low battery indication. SOLVED!

Post by Yekuku » Thu Nov 22, 2018 5:41 pm

I had a quick look on the schematics, it is an odd psu indeed.
I wish I could help more, but i have no experience on the K4.
Good luck man !
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Mooger5
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Re: KORG M1 - No sound / Low battery indication. SOLVED!

Post by Mooger5 » Thu Nov 22, 2018 8:42 pm

Thanks! When you find one, try it! If you´re into old-school ambient you´ll find this synth is special, like secret weapon special.

Cheers!
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Mooger5
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Re: KORG M1 - No sound / Low battery indication. SOLVED!

Post by Mooger5 » Sat Dec 08, 2018 4:59 pm

Well, after much testing I came to the conclusion the distortion was only caused by bad programming. The individual channels' levels must be kept low and that's it. Factory presets confirm it.
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