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Korg M3 LCD not working!

 
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Blue Eye Fred



Joined: 03 Apr 2019
Posts: 6

PostPosted: Wed Apr 17, 2019 11:07 pm    Post subject: Korg M3 LCD not working! Reply with quote

I am in bad need of help anyone!

I changed my Korg M3 Expanded touch screen panel.

Something went wrong!

I have put a new touch screen panel in and still not working. All I get are lines.

I have now replaced the LCD with a new one, (KCG057QV1DH-G68).
The keyboard starts up but nothing is getting to the LCD, only lines.

IM now trying to change the PCB board, (200060942810 KORG M3 CPU BOARD KLM-2810). I can not find one anywhere.

Does anyone know how i can get one, or if I am on the right track.

This is the sad story that goes with it. I have not played for some time. My other half got me it many years ago. She sadly passed away 18 months ago, (54 years). I started to play again so I could write something in memory of her. I was doing fine until I changed the touch screen.
Iv come to a dead end in this.
Is there anyone who can help please?
Fred
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HardSync
Platinum Member


Joined: 07 Jan 2011
Posts: 611

PostPosted: Thu Apr 18, 2019 3:36 pm    Post subject: Reply with quote

I'm sorry to hear about everything, Fred. :(

OK, I have to say that I don't know what the actual problem is, I can only guess. My guesses are that the connection between the PCB and LCD is probably bad, or that the LCD is bad. Have you tried disconnecting it all and re-connecting it? I would make sure that all connections are re-seated so they make proper contact. Have a close look at the cabling and make sure nothing is pinched or broken anywhere. I don't know where to source the PCB by the way... maybe Parts Is Parts has one?

There are LOTS of topics about the touch screen and LCD problems in this forum. Try using the search function here: http://www.korgforums.com/forum/phpBB2/search.php In the forum drop down at the left, choose Korg M3. And in the search query box at top right put in these words "LCD touchscreen display".

In one of the topics, somebody had something similar happen and maybe they got it fixed somehow? http://www.korgforums.com/forum/phpBB2/viewtopic.php?t=111258 You could try contacting them or replying to their topic.

There's also a replacement guide available here: https://drive.google.com/file/d/0BwnJAmy-gHTvRGJhdFV5ckJ1RkE/view and that came from this topic: http://www.korgforums.com/forum/phpBB2/viewtopic.php?t=84570 I think there is also a YouTube video somewhere as well.... worth reading and watching everything, in my opinion.

Worst case scenario, I did think that maybe you could try hooking up your M3 to your PC and using the M3 editor program to navigate through the sounds on the keyboard... at least until you get the display fixed. I hope you get it repaired soon. :)
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Blue Eye Fred



Joined: 03 Apr 2019
Posts: 6

PostPosted: Thu Apr 18, 2019 6:20 pm    Post subject: Reply with quote

Hi HardSync.
Thanks for reply.

Connectors have been checked, plugged & un-plugged many times. Cables also checked. The LCD should work without the touchscreen. That's only used for user input.

I will take a look at your links, thanks for that. I have already read a lot on this forum about this topic, however most was touchscreen related.

I found out 1 of the pins that goes to the PCB board was in the wrong hole, Confused .

Its this what makes me think its the PCB board. I have already tried new touchscreen & new LCD display. NO JOY Evil or Very Mad

Your idea about the PC might be the only way forward if nothing else works. Which also means not all is lost. Big thumbs up for that mate, Cool .

Regards

F
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HardSync
Platinum Member


Joined: 07 Jan 2011
Posts: 611

PostPosted: Thu Apr 18, 2019 7:41 pm    Post subject: Reply with quote

Well, bugger... sorry!

I guess before changing the main CPU board, you should look at the inverter board KLM-2649 and ensure that is working properly. And actually, if you're getting sound out of the synth, then I don't think it's the main board you want to replace. If you aren't getting sound, then yeah, maybe it's the main CPU board. I dunno though. I replaced a joystick on mine, and the new one had a similar issue to the old one, but it the problem happened in the opposite direction. Weird... I'm on the fence about buying another new joystick to see if the problem is fixed or persists. But anyway... good luck! :)
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Blue Eye Fred



Joined: 03 Apr 2019
Posts: 6

PostPosted: Fri Apr 19, 2019 11:31 am    Post subject: Reply with quote

Hi Sync,
cheers!
I did say that to Dave, He the one trying to sort out the Korg. I will try and see if I can get some sound out of it. There is another PCB board on top of the main board. This is the one i'm trying to replace.
Is there a way to test the inverted board?
I already have the main specs PDF file on this Korg & everything i could find. It has come in very handy. If any one wants a copy let me know & ill send.
Regards
Fred
ps
Did that joystick have any wire connections ?
If so maybe try swooping them. Some wiring works both ways. If the problem is still there but swoops round again. The problem is somewhere else.
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HardSync
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Joined: 07 Jan 2011
Posts: 611

PostPosted: Sat Apr 20, 2019 4:32 pm    Post subject: Reply with quote

I've got a PDF of the service manual, too. I'm not sure how to test the inverter board or even if that's the problem. I mean, it might just power the backlight or something... I've no idea. It's been a long, long time since I've had to read and use electronic schematics - like 25 years at least. I'm at the stage where I sort of get what I'm looking at, kinda understand how it all fits together, but I'm too lazy to recall to how to test what the desired output of any given circuit might be via Ohm's law or whatever. LOL. I can certainly stick a voltmeter or multimeter probe on a circuit, but I need to know what the expected voltage or resistance is. Anyway... it's a lot easier to just hire a tech to fix these things.

As for my joystick problem, it's not reversible. The connector fits only one way, and even if I could reverse the connection, then all of the modulation axes would be opposite of what is expected, e.g. JS+Y would activate when I moved the stick JS-Y. The problem I had with the old joystick was that when I moved the stick down into the JS-Y position and released it, there was a pitch bend blip happening as the stick returned to the center position. The new joystick now instead gives me a pitch bend blip when I move the stick upwards and then release it. In both cases, this happens even when I manually brought the stick very slowly to its center, default position.

I thought this was possibly a mechanical issue with the potentiometers in the joystick assembly, or perhaps the spring tension was causing it. It's just weird that the new joystick has the same problem but in reverse. Is it possible that the new one is also defective or is it something else in the board that is causing this? I just don't know. A person at Parts Is Parts said I could return the new joystick, but I really didn't feel like disassembling my M3-88 again. It's a bit of a pain.
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