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

Pulling out your hair? Don't know what to do or where to go? Ask in here.
Forum rules
READ: VSE Board-Wide Rules and Guidelines

If your Help request has been solved, please edit your first post in order to select the Image Topic Icon to let others know your topic has been solved.
User avatar
Yekuku
Active Member
Active Member
Posts: 610
Joined: Tue Nov 18, 2008 11:29 am
Gear: dk'tronics speech synthesizer :P
Location: Greece

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 !
It is all about sharing...

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

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.

User avatar
Yekuku
Active Member
Active Member
Posts: 610
Joined: Tue Nov 18, 2008 11:29 am
Gear: dk'tronics speech synthesizer :P
Location: Greece

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?
It is all about sharing...

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

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.
Herrare umanum est.

User avatar
Yekuku
Active Member
Active Member
Posts: 610
Joined: Tue Nov 18, 2008 11:29 am
Gear: dk'tronics speech synthesizer :P
Location: Greece

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 !
It is all about sharing...

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

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!
Herrare umanum est.

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

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.
Herrare umanum est.

WORKSOP
Newbie
Newbie
Posts: 2
Joined: Sun Oct 06, 2019 10:07 pm

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

Post by WORKSOP » Sun Oct 06, 2019 10:16 pm

Yekuku wrote:
Tue Jan 17, 2017 9:27 am
According to the schematics , the green thingies are inductors, 47uH.
Inductors rarely fail, you better replace C21 , it is bulged.
The L4 one on my board has failed, you can see the damage like corrosion around the bottom, I'm familiar with capacitor replacement (the blue type) but haven't come across this component "inductors" any help sourcing some replacements :D

I replaced the battery and installed the sounds, that worked but obviously no sound please help any one?

User avatar
Yekuku
Active Member
Active Member
Posts: 610
Joined: Tue Nov 18, 2008 11:29 am
Gear: dk'tronics speech synthesizer :P
Location: Greece

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

Post by Yekuku » Mon Oct 07, 2019 11:01 am

Hi WORKSOP and welcome to the forum.
I cant see the photo that you have posted , so I cant help much.
The L4 is an inductor (coil) and when coils fail they dont produce corrosion , they are either "open" or partially shorted.
Have you done a factory reset after the battery replacement ?
It is all about sharing...

WORKSOP
Newbie
Newbie
Posts: 2
Joined: Sun Oct 06, 2019 10:07 pm

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

Post by WORKSOP » Mon Oct 07, 2019 1:47 pm

Yekuku wrote:
Mon Oct 07, 2019 11:01 am
Hi WORKSOP and welcome to the forum.
I cant see the photo that you have posted , so I cant help much.
The L4 is an inductor (coil) and when coils fail they dont produce corrosion , they are either "open" or partially shorted.
Have you done a factory reset after the battery replacement ?
Thanks for the welcome nice to meet you, yeah the inductor has corroded looks like the "glue" has had a detrimental effect over time and made it corrode.
I have replaced the battery and reinstalled the sounds, but it still came up with the low battery message, thats when I looked and you can see the damaged inductor thing, the capacitors all look fine, I have changed these before on a TV but havent got any experience with the inductors. I have taken the board to an electronics guy I know hes going to have a look hopefully he will get it working. :?

User avatar
Yekuku
Active Member
Active Member
Posts: 610
Joined: Tue Nov 18, 2008 11:29 am
Gear: dk'tronics speech synthesizer :P
Location: Greece

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

Post by Yekuku » Mon Oct 07, 2019 5:35 pm

If you could post a picture , it would be easier for me to understand whats going on.
The glue that is used to hold components in place, sometimes gets corrosive and destroys surrounding parts.
Did you check the voltages on the power supply ? (+12V/-12V/5V )
Good luck !
It is all about sharing...

Post Reply