The keyboard works fine but i think i pressed something so now it only lights up on some keys and it plays like 3 notes or 4 notes at once depending on what keys i hit i would like to know how to reset the keyboard to put it back to factory settings ... i have a casio lk 100

Water/ moisture damage corrosion of electronic connections or power supply cooked certain chips on motherboeard maybe melted after heating up to much

Below the keyboard, there is a rubber contact (see figure 1). Damage to the contact rubber can cause:
- Note plays loudly or
- Note does not plays at all.

It is caused by:

1. Carbon rubber contacts dirty / dusty (yellow arrow). Clean with a pencil eraser (or cloth). Gently rub it.

2. Contact shredded rubber. If this happen,it can not be repaired or glue. So, you have to replace one octave as in Figure 1.
The yellow arrow indicates the side that is often torn.

Hi, This and a lot of similar keyboards have gold flashed pads on the PCB and the keys press one or two rubber caps, with conductive pads in them, down.
Clean the pads with isopropanol, (and nothing else) and it will be cured 99% of the time. If a few notes do not work, especially after heavy use, then the rubber caps can be replaced.
Taking the keyboard apart is long winded because of the number of screws involved.
The job its self is simple enough, but take note of the order things go in and where the screws go.
Hope this helps, Chris.

If you connect to PC using USB interface, then use a commercial midi player - e.g Melody Assistant or Harmony assistant to play MIDI files to it.

Or else download "SMF convertor" to convert midi files and download compatible file to keyboard.

Check the switch to be sure the keyboard is in normal mode and not chord mode. This will cause there to be no sound unless you play a chord on those first 11 keys. Pressing play activates whatever song is loaded at the time, allowing full keyboard use.

I have an older Casio, and the same thing happens all the time, especially when I'm in a hurry and don't check where I put the switch.


Hope that helps!

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/cameron_463100ffd54b591d

I have found my schematics. The F3# and the C3 and E3 all have common interconnects in the key scanning matrix.

The following diodes on the key contact board need to be checked:

D49, D50, D57, D58, D61, D62.

These diodes block the hazard paths of the scanning when more than one note is held down.

You MAY find some contamination is shorting one of the diodes rather than the diode being bad itself.

The scanning is of a conductive rubber key contacts so is high impedance as the contacts don't go near zero ohms when pressed. Leakage in the diodes can cause the problem. I would first visually look for shorts on the board affecting the conductors tied to these diodes.

Clean the board and contacts with 99% isoprophyl alcohol and Qtips.

You will have to remove the sets of keys that are held with several screws. I believe they are modular and the keys are in groups of white and two black groups per octave. Under the keys is a silicone strip of domes with conductive pills, two per note that are pressed onto the board. The two contacts close at different times so they can measure key velocity.

The key contact circuit board is in two parts, a high and a low section. To remove, you will have to remove all keys and the silicone strip over the section of board of interest.

Most of these have VELOCITY sensing and that involves two contacts per note. If the velocity sense on those notes is somehow not working, broken wire or trace on the board or short that MIGHT cause your problem.

You are suffering from midi latency. There is a good article about this at www.thewhippinpost.co.uk/latency.htm There is also some good advice there.

There are 17 screws on the underside of the keyboard that need to be removed. The base cover can then be removed. This gives access to the keyframe assembly which can be removed.

what is make and model? I have owned several keyboards, with 2 of them Korgs in which I would connect a damper pedal. I noticed that when I help down the pedal, after so too much input within the cpu of the keyboard, it would 'short-circuit' and sound like I had played an 'off-key'

If you have been using the damper pedal, and even if you release a little on up on it, but not all the way, the 'off-keys' will still sound. I must always make sure the pedal is placed in a position that my leverage action of my foot will completely 'release' the overtones still being processed by the keyboard (whether they're audible or not)