Page 3 of 4

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

Posted: Wed Jan 15, 2020 4:49 pm
by Yekuku
Hi flyingsaucer and thank you for your kind words.
Just use a sharp cutter and cut the epoxy glue perimetrically at the base of the caps.
You should be able to desolder the caps without problems.
there is no reason to remove the remaining epoxy glue from pcb unless the epoxy is in contact with other electronic components. Sometimes epoxy glue deteriorates and corrodes components.

Good luck !

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

Posted: Wed Jan 15, 2020 5:35 pm
by flyingsaucer
Yekuku wrote:
Wed Jan 15, 2020 4:49 pm
Hi flyingsaucer and thank you for your kind words.
Just use a sharp cutter and cut the epoxy glue perimetrically at the base of the caps.
You should be able to desolder the caps without problems.
there is no reason to remove the remaining epoxy glue from pcb unless the epoxy is in contact with other electronic components. Sometimes epoxy glue deteriorates and corrodes components.

Good luck !
Thanks a lots for your answer could you please look at my previous post? I'm also integrating with new photos and question.

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

Posted: Fri Jan 17, 2020 6:38 pm
by flyingsaucer
@Yekuku Thanks a lots... I've succeded in cleaning.. removing everything.

Before
http://imgbox.com/BPtviwAu

After
http://imgbox.com/kPDkZvW6

Final job!

http://imgbox.com/uP2Gz0zE
http://imgbox.com/xIbeeV0f

I've cleaned coil and reused, then I've removed original:

Big One
C11 47 microfarad 400v (85°C) ---- new C11 - 47 microfarad 450v (105°C)
C18 220 microfarad 25v (85°C) ---- new C18 - 220 microfarad 35v (105°C)
C19 220 microfarad 25v (85°C) ---- new C19 - 220 microfarad 35v (105°C)
C20 220 microfarad 25v (85°C) ---- new C20 - 220 microfarad 35v (105°C)
C21 220 microfarad 25v (85°C) ---- new C21 - 220 microfarad 35v (105°C)
R21 NEW 560 Ohm
R20 NEW 560 Ohm
C22 2200 microfarad 10v (85°C) ---- new C22 - 2200 microfarad 16v (105°C)
C23 2200 microfarad 10v (85°C) ---- new C23 - 2200 microfarad 16v (105°C)
C24 1 microfarad 50v (85°C) ---- new C24 - 1 microfarad 63v (105°C)
R22 NEW 220 Ohm

Power Supply KLM - 1269 NEW!!!

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

Posted: Sat Jan 18, 2020 11:08 am
by Yekuku
well that was fast ! great work man :)

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

Posted: Sat Jan 18, 2020 12:31 pm
by flyingsaucer
Yekuku wrote:
Sat Jan 18, 2020 11:08 am
well that was fast ! great work man :)
Thanks a lots! These days it's cold outside in the morning 0°-2°C I've put 20 minutes my power supply on balcony; then I've used a needle to crumble the resine/glue. Then desoldered components and soldered new ones.
Could please help me to find where recap these one? They where parts of my incomplete kit.

http://imgbox.com/bzz7wZbu

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

Posted: Sun Jan 19, 2020 9:32 am
by Yekuku
Hi flyingsaucer,
these are tantalum caps 10uf at 35 V. I did a quick check on the schematics, but i could not find any 10uf cap to replace.

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

Posted: Sun Jan 19, 2020 7:13 pm
by flyingsaucer
Yekuku wrote:
Sun Jan 19, 2020 9:32 am
Hi flyingsaucer,
these are tantalum caps 10uf at 35 V. I did a quick check on the schematics, but i could not find any 10uf cap to replace.
Thanks for helping, maybe they are used in KLM 1267 and KLM 1268 power supply. Now I'll wait for no polarized capacitors shipment by ebay seller and then I'll go on recapping mainboard, DAC and tactiles command board.

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

Posted: Sat Feb 01, 2020 5:45 pm
by mirzaa
Hi,

I got one M1 with same symptoms. First was low batter warning. Battery changed and reproduced no sound. Next was changing all electro capacitors and inductors. Voltages are +/-12 ok but 5V rail outputs 4.2V and its trimmer doesn't give me much play to go to 5V. After power up I can hear faint sound from headphones but synth freezes after few seconds. In that time I can access menu and change parameters but it's only for couple of second. What to do next? New PSU board?

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

Posted: Sat Feb 01, 2020 8:42 pm
by mirzaa
ok I got stable 5V, it was faulty trimmer.
Now it boots, it accepts factory presets but still no sound. Infact sound is there but really faint and only on left channel. I have to turn volume to max to hear it faintly. What to do? Please help

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

Posted: Sun Feb 02, 2020 1:13 pm
by Yekuku
Hi Mirzaa,
Since you are getting correct voltages on the +/- 12 voltage rails, the problem should be on the DAC card.
Check R79 in the DAC board (KLM-1261), it should be 10 Ohms.

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

Posted: Tue Feb 04, 2020 5:59 pm
by mirzaa
Yeah that R79 is charcoal black. Gonna replace it in the morning.

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

Posted: Tue Feb 04, 2020 9:31 pm
by mirzaa
It is fixed!!!! Thank you!

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

Posted: Wed Feb 05, 2020 9:34 am
by Yekuku
Great news! Enjoy your M1 🙂

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

Posted: Thu Feb 06, 2020 8:22 am
by flyingsaucer
Yekuku wrote:
Wed Feb 05, 2020 9:34 am
Great news! Enjoy your M1 🙂
Number 1!!!!! This is one of the best topic on Korg m1.
@Yekuku thanks a lots!

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

Posted: Mon Feb 10, 2020 4:05 pm
by HeMagliano
Hi, I have the inconvenience of battery low (internal). According to what I read, I initially changed the C23 for a new one, and everything remained the same. Then I changed the rest (c11,19,18,21 ... etc) and it keeps telling me the same error. Any idea what the fault may be? I inherited the keyboard. my father used it to work, and when he died it was me. It was a while without being used and when I turned it on it said that error. I had the programs but did not emit sound. I changed the battery and it was reset and I could not remove that low battery message.
Thank you!!