Korg Forums Forum Index Korg Forums
A forum for Korg product users and musicians around the world.
Moderated Independently.
Owned by Irish Acts Recording Studio & hosted by KORG USA
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Korg 01/w problem with buttons on control panel

 
Post new topic   Reply to topic    Korg Forums Forum Index -> Korg Synths (General)
View previous topic :: View next topic  
Author Message
SerErris



Joined: 25 May 2018
Posts: 14

PostPosted: Wed Jun 06, 2018 12:24 pm    Post subject: Korg 01/w problem with buttons on control panel Reply with quote

Hi,

I created a problem on my own and now stuck in troubleshooting the issue.

Situation:
Control Panel buttons A-G and the 8 buttons left (PROG/COMBI etc), are not working. All other buttons working. It is not the "button" broken or stuck issue, as the buttons electronical do work and clearly creating a contact (measured with multitool).

What I did (not sure if that is anyhow related).

I resoldered a few buttons, but it still worked after that.
I changed the display to a new LED backlight display. This works. It also worked after simply plugging in the new Display. However it was to bright, as expected as the contrast ratio is not correct anymore.

I then replaced R149 from 220kO to 180kO (as defined in the manual for the display).

Then I plug everything back in place and since then the said buttons do not work anymore.

The display hack indeed is working! ...

Looking at the diagrams in the Service Manual, it looks like line 12 and 14 of the connection from panel to main pcb is somehow the issue, as that is the only reason, why it would not work anymore.

however ... all lines in the cable working and I also cannot identify any button not working, or any other shortage. All diodes on the panel pcb are working as well ...

I also scratching my head if the Display hack could be the root cause) .. But cannot see any point how this could be related looking on the cirquit diagrams.

Any Idea how to narrow down the issue? How can I measure e.g. if the issue is on main PCB or on panel PCB?
Back to top
View user's profile Send private message
SoundWerx



Joined: 10 Oct 2011
Posts: 16

PostPosted: Thu Jun 07, 2018 3:47 am    Post subject: Reply with quote

Hmmm, from what I can gather here you swapped out the resistor on a board? I've done 4 of these replacements, 3 on my 01R/W's and 1 on my 01W/FD. In every case I removed the EL Foil inverter off the power board and used the +5v from there to power the LED display backlight.

The big difference being I used an INLINE resistor on the +5v wire to the display. I've never had a problem, contrast works perfectly. I can't say for sure if your resistor swap out has introduced the problem. If it were me I would check the traces on the panel to make sure none have been broken or shorted out. Once I'm sure that is OK I would start to retrace my steps and consider putting back the old resistor to rule that out.

Good luck!
Back to top
View user's profile Send private message
SoundWerx



Joined: 10 Oct 2011
Posts: 16

PostPosted: Thu Jun 07, 2018 3:54 am    Post subject: Reply with quote

Ahhh, can I assume (I read your post again) you purchased a pre-wired display from eBay and it derives it's power from the pin header rather than using power directly from the power supply like my mods?

The question for me would then be what else is affected by changing that resistance? Smile
Back to top
View user's profile Send private message
SerErris



Joined: 25 May 2018
Posts: 14

PostPosted: Thu Jun 07, 2018 11:13 am    Post subject: Reply with quote

Hi SoundWerx,

thanks for your input. Yes you are right, I baught a prewired device from eBay, where I just need the Display Connector. The Power connector for the backlight is completely removed.

There is no other connection from the Main PCB to the Display then the one ribbon cable.

That is so far working good .. display is on, displays the normal page and is also from brightness point of view correct.

I also can walk through the sounds and even that works as epxected.

However I cannot change to the Global Menu or to any other Menu. I will stick in Combi Mode.

Next thing is: I will try to manually switch. The matrix from the service manual is very helpful to understand which two pins on the connector on the main pcb need to be connected to create a result.

That shall demonstrate if the L2 or L4 are broken, (anywhere between connector and the Matrix Chip) or if they are okay.

If everything on PCB is okay - then it must be somewhere on the Panel. The only issue is - there is really nothing on the panel which could break.

Okay, again thanks for your input. And of cause I would love to avoide removing the resistor again Smile
Back to top
View user's profile Send private message
SerErris



Joined: 25 May 2018
Posts: 14

PostPosted: Fri Jun 08, 2018 9:18 pm    Post subject: Reply with quote

Okay,

I fixed it.

After running around in my completely disassambled Synth with a multimeter, I idenntified, that it is just the ribbon connector on the Main PCB not haveing good contact is the issue.

It was so unlikely that this could be the issue but by chance one time plugging it in, I got the contacts working and then identified that it was simply the connector.

Okay anyhow I learned a lot about the 01/w Smile

And now I have all buttons replaced, All Elkos replaced and everything completely cleaned ... Smile

So it is more or less now a brand new 01/w Smile

Cheers.

Ser
Back to top
View user's profile Send private message
SoundWerx



Joined: 10 Oct 2011
Posts: 16

PostPosted: Sat Jun 09, 2018 7:50 pm    Post subject: Reply with quote

Nice work! It was pretty clear to me from your previous posts you had the skills to track it down. I hate it when something like that happens and you start to second guess everything Rolling Eyes

Happy you got it fixed!!
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Korg Forums Forum Index -> Korg Synths (General) All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group