Beding wheel gone wild

ltpitt · Post by **ltpitt** » Thu May 03, 2012 5:07 pm

My bending wheel goes crazy sometimes.

It stops working at all or it bends random tones insted of tones I've set.

The problem presents itself randomly.

I've tried disconnecting the bending wheel cable with the r3 turned on and then connecting it back: the problem gets fixed perfectly.

What could it be?

ò_ò

ltpitt · Post by **ltpitt** » Tue May 22, 2012 9:27 pm

ps

it happens almost everytime I connect the usb cable to the computer

ltpitt · Post by **ltpitt** » Wed May 30, 2012 2:52 pm

pps

I hate this

ltpitt · Post by **ltpitt** » Mon Sep 03, 2012 8:01 pm

My problem is still killing me

I did a live gig last week and what happens is that my r3 gets out of tune

I turn it on and push "c" and I get something "moving" between "c" and other notes

If I use the bending it barely moves of 2 tones even if it's set on the whole octave

If I open up the r3 (warranty is already gone) and unplug both benders it gets back to normal...

What could it be?

axxim · Post by **axxim** » Mon Sep 03, 2012 9:05 pm

ltpitt wrote:My problem is still killing me

I did a live gig last week and what happens is that my r3 gets out of tune

I turn it on and push "c" and I get something "moving" between "c" and other notes

If I use the bending it barely moves of 2 tones even if it's set on the whole octave

If I open up the r3 (warranty is already gone) and unplug both benders it gets back to normal...

What could it be?

It could be a cold solder junction or bad contact on the connectors. Usually this behavoir is from a poor ground or supply contact thru the boards. A good method for cleaning contact pins (if they are accesible) is rubbing them gently with an eraser (those bicolor ones that are for pencil and ball pens) with the white side. Maybe you should trace the connectors that deliver the power to the board until you reach the one that goes to the pitch bender. You may also measure the voltage between the the two extremes of the pitch bend potentiometer and look if the supply is stable enough (usually there is a reference voltage for all potentiometers that may have 2.5V, 4.096V or whatever else). You can measure other pot terminals to find out if there are different. If you happen to get the schematics from the R3 maybe then I can give you more hints on what this issue could be.
Do you have the original power supply from the R3 or is it a substitute?

ltpitt · Post by **ltpitt** » Tue Sep 04, 2012 10:28 pm

Gone

Now the volume is VERY low even at maximum.

With frustration I gave a light punch on it and it was back working.

Then it become very low again

X-Trade · Post by **X-Trade** » Wed Sep 05, 2012 7:35 am

If you don't know how to diagnose and fix it yourself, you need to take it to a keyboard tech or at least someone experienced in repairing electronics.

It's not something that can be explained or directed very well over a forum.

Basically, if you had the skills required to fix it then you wouldn't need to ask. You need to be good with a voltage meter and a soldering iron.

ltpitt · Post by **ltpitt** » Thu Oct 04, 2012 8:38 pm

axxim wrote:
ltpitt wrote:My problem is still killing me

I did a live gig last week and what happens is that my r3 gets out of tune

I turn it on and push "c" and I get something "moving" between "c" and other notes

If I use the bending it barely moves of 2 tones even if it's set on the whole octave

If I open up the r3 (warranty is already gone) and unplug both benders it gets back to normal...

What could it be?
It could be a cold solder junction or bad contact on the connectors. Usually this behavoir is from a poor ground or supply contact thru the boards. A good method for cleaning contact pins (if they are accesible) is rubbing them gently with an eraser (those bicolor ones that are for pencil and ball pens) with the white side. Maybe you should trace the connectors that deliver the power to the board until you reach the one that goes to the pitch bender. You may also measure the voltage between the the two extremes of the pitch bend potentiometer and look if the supply is stable enough (usually there is a reference voltage for all potentiometers that may have 2.5V, 4.096V or whatever else). You can measure other pot terminals to find out if there are different. If you happen to get the schematics from the R3 maybe then I can give you more hints on what this issue could be.
Do you have the original power supply from the R3 or is it a substitute?

Excuse my absence but I was (thank god for giving me a little rest from work) on holiday!

I'm back and you theory seems to me very close to the truth: a cold solder junction is _almost_ gone.
Just moving a bit the keyboard or pushing harder the keys make it work again.
I have a little gig on the 6th so I'll play disconnecting the bending and modulation: this way it gets in perfect tune.

In the meanwhile I'll look everywhere on the internet to find service manual (if anyone has it I'd GREATLY appreciate a copy) to look out for the almost dead cold solder junction.

Maybe I'll ask again for your kind help, axxim!

I've also read X-Trade wise suggestion and I've found out a close Korg repair shop: if I'm not able to find it fast and easy I'll take it there.

I'll keep news posted with pics so in future nobody will suffer like me (AAAAARGH).

For now thanks to everybody.