Doremikko Keyboard Repair Possible?

[Flemishdog]

So I have the chance to buy a cheap copy of Doremikko, but the seller says the keyboard has a few keys that don't work. is it possible to repair it? Could it possibly just need a clean so that dirt isn't stopping a key making contact?

[P]

Possible but depending how damaged it is, it may be hard to do. If you are lucky cleaning may be enough.

[80sFREAK]

photos?

[Flemishdog]

I've only got an auction photo. it looks like its in good condition otherwise:

[80sFREAK]

Thanks for the photo. Now you have to split it apart and take a photo of the guts. Sorry, i never had this keyboard, so have no idea, how keys working. There might be some sort of microswitches(buttons) or controller(pad)-style conductive rubber.

[zmaster18]

It looks great in the photo. I also think that since the owner has kept all packaging, he took good care of it. I would go ahead and get it. A good cleaning should do it. I totally want to get myself one of these Konami keyboard sets one day!!!

[zmaster18]

I recently got a boxed Doremikko set and some keys don't work. The keys that didn't work followed an exact pattern, so this must be something electronically not connecting properly. Im going to start with cleaning it fully.

So the keys that don't work are all 3 of the F keys and B keys.

[P]

So it's probably not fixable by cleaning, too bad. I guess the next step is to look on the PCB for bad components, damaged traces etc. Then replace all the electrolytic capacitors.

[zmaster18]

I took the piano apart and looked at the board. After checking many solder pads with my multimeter, I finally found a component that wasn't connecting - a little ceramic capacitor. I will have to replace this. When connecting the 2 solder pads together the piano was working perfectly after.

I'm going to give the plastic keyboard a good cleaning and also some lubrication. Some keys are a little squeaky. Anyone have any ideas? I was going to completely wash the whole plastic assembly and then use WD-40 on the metal bar and in between the keys to smooth things up!

Edit: Soldered in a 220pf capacitor instead of the 100pf that was installed before. When I put in a new 100pf cap it still wasn't working, but using 220 made it work. Now all the keys work!!!!!! This spot on the board is labelled C2.

[P]

Good that you got it working but strange that a 100 pf cap didn't work. Maybe there is something else that is wrong with it which is somehow fixed by the 220 pf. Maybe you should check the rest of the components as well.

I'm going to give the plastic keyboard a good cleaning and also some lubrication. Some keys are a little squeaky. Anyone have any ideas? I was going to completely wash the whole plastic assembly and then use WD-40 on the metal bar and in between the keys to smooth things up!

That's what I'd do too. First clean with isopropyl alcohol then use silicone spray on movable parts that needs lubrication.