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just bought a korg concert 3500 keyboard but a few keys are slow/nonfunctional. one of the keys is louder then all the rest. from what ive been reading, it sounds like the contact pads might be dirty and/or keys need to be lubricated. im not really sure how to go about disassembling the unit as it didnt come with a user or service manual. any ideas how to go about disassembling the unit or some kind of safe lube/cleaner that could be sprayed in the area? thanks!

I had a similar problem with my Nord Electro keyboard - two (adjacent) notes weren't 'playing'.

I sought some advice, and I learnt that a 'saturation' with a spray cleaner could be
potentially disasterous..... DON'T DO IT!!!!!!!!

The general rule to dismantling a keyboard is -

the screws (usually on the underside) that are in a stright (normally double) line are the
ones that hold the actual keys/keybed in place.

The ones to undo first are the ones that hold the 'case' in place.

After that, use a cotton bud (moistened with contact cleaner) to gently clean the contact points.

A heavy-handed spray of everything could lead to all kinds of problems.

.

im still kind of confused. i have screws underneath that take off the front panel so i can see the underside of the keybed, and then i have 5 screws in a line on the underside of the unit. if these are holding the keybed in, im not sure how to get the keybed out. oh also, the keybed will come out in 1 solid piece, right? i went down to my hardware store and bought some contact cleaner, white lithium grease, and q-tips... i just cant figure out ho toget the damn keybed out! will it take some force to get it out or should it just slide right out?

If this is a new keyboard it should be under warranty by the manufacturer. Trying to fix it yourself will (most likely) nullify the warranty. It sounds like the keyboard is defective. The best thing to do is to look into returning it.

it's not a new keyboard and is not under warranty. in fact, i can barely find info on it because they were made in the very late 80's. it was one of the first ever keyboards to support midi from what i hear. i really dont have many options as i live in a somewhat rural area and have limited options for finding a repair shop that would work on it. i'd like to try to tackle this myself.

NO - you shouldn't have to 'force' anything.

.

that's what i figured, i just cant figure out how it's going to come out, or how i can access the contacts.

if anything sems to be 'snagging' - take a closer look.

All these things were connected one-by-one in the original manufacture -

so they can be 'dis-assembled' in the same way.

PS - make sure you keep a note where you've removed the screws/connections from !

.

nothing's really "snagging". ive loosened every screw i can find and the keybed barely moves at all.

There must be an extra screw/connection somewhere that you're missing?

i cant even see any of the connecters. i cant even get the case fully open

it's bedtime for me now (3.15 am in the UK) -

I'll try to work on an answer for you in the morning.

a few photos to hopefully help you with what im looking at here. the silver things on the bottom appear to be non-removable and it looks like they hold the speakers

so i figured out how to get the case off and i cleaned the circut board off (it looked like something sticky had been spilled and dried on it). all my keys are now functional. wohoo!!! the only problem im looking at now is the 2 keys that are playing at maximum volume no matter what velocity you hit them. oh also, i have 1 or 2 keys that sometimes stick or stay down when you play them. im guessing they just need to be lubricated, but im not sure exactly which part of the keys need to be lubricated. any help?

Hi,
I have just 'repaired' keybed on a korg 3500.
To open the casing remove the black scresw (bolts) underneath. You may have to take the keybord off the stand (heavy!!). After removing screws, be careful with moving it, because actual keybed will lay somewhat loose in the case and could damage the printboards in the casing. When the casing is right side up, it should open like the hood of a car. Mind that there are some cables that limit opening to about 90 degrees.

Keyboard is connected with main print boards by flatcables, you can remove these. Then remove keyboard and put it upside down. You will see three long printboards under keyboard, each with some screws to hold them into place. Remove the scres, and remove boards (you might want to mark which board belongs where, they are NOT interchangeble, or take picture of them..).
Then you will see a long white soft plastic strip, with 2 black contact strips on the other side. You can totally remove this strip, clean it with non-agressive cleaner (cloth with a bit of household cleaner), let it dry thouroughly and place back. Is also a good idea to clean the contact points (w dehydrated alcohol) on keys, while you are at it. You should also examine if the white strip isn't damaged. A piano repairist I consulted told me this sometime happens. Replace parts are however still on the market (by yamaha service centre here in the Netherlands). When you replace strip make shure it is not under stress somewhere.
Then replace the prints, etc.

In my case the keyboard had a little damage form water, and I had to replace two of the long prints on the keyboard (were not very expensive, about 30 US dollar each). Could also be the case with your keyboard.

Succes with repairs. If you have trouble opening the case i could send you some photo's.

Funny you mention this piano. I played a concert 5000 for 20 years. bought it new in late 80's for $2500 and it never gave me any problems. I even lugged that tank to a couple gigs! Sold it at a garage sale for $150, prolly got ripped off but wifey was on me to make it gone.

Hello everybody.

I just had the same story, i found a C-3500 in a garage sale few weeks ago. Same problem with the center of the keyboard. I open it and totaly unmount. I clean every key with white spirit, then remount them using silicone grease (usually used for taps lubrification in plumbery).
But the white long strip, the one with the two black line which conducts is damaged in the center of the keyboard. As result, the center octave is no longer ok, no dynamic, no softness.
So i read your post and my question is : "where did you found spare parts ?" Here in france it's seems really hard ; no piano repairist wanted to even think of looking for it... Do you think your own reseller could sell it to me ?
Regards from France,
Antoine