Repairing Korg Krome's blank screen

I'm posting this here in hope that it helps other people facing the same issue.

This week-end, my Korg Krome synth's display became blank again. Given that it's a touch device, it becomes pretty useless once the display doesn't work anymore. It's not the first time it happens, I even disassembled it once hoping it was only a cable or solder issue, but it worked again after being reassembled for no apparent reason. I noticed that often after it failed, it would re-appear after a few hours/days, and sometimes it would disappear again. I thought the LCD was dead. I ordered a new one on the net (almost any 7" 50-pin LCD with a resolution of 800x480 and about 15cm of cable will work). It cost me $15, it worked and failed again after one week. 

Finally I disassembled the Krome again and observed the LCD power board, and found that the LCD reset pin (44) had a strange voltage of 1.5V instead of 3.3V. The reason is a design error in the choice of resistor R28. It's 10K while it should be around 1K. With 10K it doesn't have enough strength to completely release the reset and it depends on the LCD's tolerance (which probably changes with aging). 

I simply soldered a 1K resistor on top of it, verified that the voltage on the reset pin is now 3.3V, and the problem is now fixed. 

In order to fix it, one must proceed like this : 

1) put the Krome top-down on a soft surface like a bed. Take care of not putting too much strength on the joystick 

2) remove all screws on the back. There are a lot, something like 37. Important : there's no hidden screw, so it's not needed to remove the rubber feet. 

3) gently pull the back vertically, it will very easily come. If it doesn't, you forgot a screw. 

4) you'll see the mainboard at the center, close to the back where the SD card is. You'll have to remove the screw with the plastic washer, and gently pull the soft plastified tin foil which protects against radio emissions I guess. 

5) then remove all cables going to the motherboard (no risk to confuse them later, though it's better to take a photo). In order to remove the flat ribbon at the bottom, you first need to pull the brown part of the connector outwards to unlock it (do not force, it will come by alternatively pulling each extremity with your nail). 

6) remove the 6 screws from the motherboard, then take the motherboard out of the system. 

7) remove the metal frame that supported the motherboard. 6 screws again IIRC. 

8) you now see the small board with its cables like in this photo :

LCD controller board
It is not strictly necessary to remove the board to fix it but it's better as static electricity could destroy the LCD. The large flat cable at the top goes to the LCD. The small one on the top right is for the touch pad. The other small one at the bottom right goes to the audio board on the right. In order to remove the LCD cable, you first need to pull the white part of the connector upwards to unlock it (do not force, it will come by pulling with your nail). The other ones need to be pulled in their own direction without bending them. 

9) remove the 2 screws holding the board, and slightly unscrew the 4 other ones holding the metal frame so that you can get about 2-3 mm of clearance. That will be enough to release the board from the 2 plastic tips which hold it. 

10) find the resistor on the board. It's called R28 and marked "103" (10*10^3 ohms = 10K). There are two such resistors at the bottom left of the "CN17A" marking. The upper one is R29 and doesn't need to be touched. The bottom one is your friend. These two photos help locate it better, click on them to zoom in : 
Resistor R28 and marking
Zoom on R28 and LCD pin 44
11) DO NOT REMOVE IT! It's a small component, if you're not at ease with soldering small components, you'll certainly destroy the board by pulling off a copper lane. Instead, just find a 1 to 2k resistor on another unused board such as a dead motherboard. Such a resistor is marked 102 to 222. Note that the first two digits are less important than the 3rd one which is critical (exponent). It MUST in fact exactly be "10" to "22" followed by a "2". If you have something smaller than a 2 on the last digit, reset will never work. If you have something larger, your fix is useless. 

12) Once you've found this new resistor, directly solder it on top of R28. If you're having trouble soldering something that small, first stick it on top of the other one using some superglue then put a very small drop of solder on each side and that will be all. You must not heat it more than 1 or 2 seconds per side. The amount of tin to add is around 1mm * 1mm only. 

13) verify with an ohm-meter that you have slightly below 1-2k when you measure across the previous 10k resistor. If so you did it fine. 

14) reinstall the board, then tighten the metal frame's screws, screw the board, reconnect all connectors (be careful with the small ones, you don't want to bend them or they could cut). Then pass the motherboard wires that you might have moved close to the board, reinstall the top metal frame, then the motherboard, reconnect all wires and power on. It must work. Once it's OK, you can finish to reassemble everything. 

I noticed that black screws are used outside and grey ones are used inside, except a few holding the LCD frame and the keybed which are also black. 

Try not to mark your screws. A screwdriver made for PC parts is perfect and will not mark. Count around 10-15 minutes just to disassemble everything, about as much to reassemble, and as much to fix the board once you have found a suitable resistor. 

If you don't have a resistor, you can find one at an electronics components shop. Just go there with your board and they'll find the proper size. I guess it's a "0603" type of resistor (it indicates the size) though I'm not certain and forgot to measure. 

I forgot to say, I noticed that the original Krome's LCD is of very good quality. When you replace it with a cheap one, images are really ugly. But that was better than nothing. 

Hoping this helps other people! I've read on various forums that many other people got in trouble with the same issue and it's too bad that some repair shops take them hundreds of bucks to fix this. So do not hesitate to spread the message and to share your experience.


  1. Mr Tarreau, THANK YOU THANK YOU for posting this material! We have a Korg Krome, and the screen has been out for months. I was researching ordering one, and then found your post. We did it (with a regular 1K resistor) AND IT WORKS! Thanks again!

    1. You're welcome. I'm really glad this post was useful. I know the frustration you've gone through with this device not being controllable anymore. By the way mine still works pretty well one year after the fix.

  2. Hi does it retain the original screen or is it replaced?

    1. Yes I kept the original screen as it's of much better quality than the replacement part I ordered.

  3. Hi Mr Tarreau. I know that this post is old but i was just wondering if you don't have any experience with the Korg Krome touch screen. My screen didn't respond to any touch. So i did buy new one from Korg and i did replace it today. But the new screen is not working ether. So i am guessing that could be some different issue. Do you have any suggestion? I did try the calibration but since the screen don't respond any touch i couldn't do it. Thank you. Pavel

  4. Unfortunately I don't have any suggestion. It may be possible that the touch panel connector is damaged or is attached to a cut copper lane. It's the "TP" connector at the top, you may want to follow the lanes to try to spot any defect. Otherwise I'm afraid you may have to change this board and it might be expensive despite being almost empty :-/

  5. Hi, Mr Tarreau,
    I seem to be experiencing the same issue. As I am a novice to circuit boards I thought it might be a good idea to get another board before attempting the surgery. Then I have at least one circuit board in one piece. My problem is finding the part number of said board. Would you know this, or where I can locate it before pulling the Krome 88 apart?

    Many thanks in advance

    Andy Partington

    1. Unfortunately I don't know. There is little risk if you're cautious. The most important you need is a fine soldering iron. If you use a large one as found in many shops, you will damage the board.

      If you don't feel easy with soldering, there's an alternative. You can use a bold pencil (2B/3B) and "draw" on the existing resistor until you can't read the value anymore. It will deposit some graphite and will lower its resistance. This may work for some time.

      Otherwise you can probably find a friend around you, more at ease with a soldering willing to help you on it. It's a very simple task which takes only one minute for trained people. The boring part really is to open the cover, but you can do it before he comes ;-)

  6. Thank you, Sir, and thank you for the extremely fast response. The use of a pencil seems quite a novelty, will give that a go for starters. Thanks again, have a great day.


  7. Hi Willy my name is luis and i am an italianna wanna be musician(my real job is security officer)and hava problem with the touch pad of my korg krome....the display is black with a yellow strip on the left side...if I touch it i can hear the response with the standard beep or buzz....do you think it is the same problem that you experienced?thanks for your kind response .luis

    1. Hi Luis,

      oh yes, it definitely sounds very familiar. I feel sorry for you, but at least you know there's a workaround now :-)

      Don't be afraid by the operation, it's long but not very difficult if you take your time. Also take some photos while doing it. If you don't have a resistor to place on top of the existing one, you can try the pencil trick, it'll just be harder to know when you've put enough of it.

  8. Thanks Willy for your quick response,one of my best friends is an electronic guru so I will bring my krome to his laboratory......i wish to you a very happy new year....ciaoooo

  9. You are the best brother..all i can say is Godbless you and thank you so much...you have a good heart thank you for sharing this knolege 😊🙏

  10. That is indeed the problem with the Krome's screen. Thank you very much for sharing your experience. I am very grateful to you for helping to solve problems.

  11. Hi willy ..you site is awesome thank you in advance for advise on an issue I have . I have korg krome 88 that the LCD screen is cracked and is only responsive on upper left hand corner . Can I just replace the glass or do I need to replace the whole display?

  12. I don't know in your case, however the LCD, the touch sensitive part and the front glass are 3 separable parts. If the glass is cracked only, maybe you can replace just it. If the LCD itself is cracked you'll have to replace it. But if it's not responsive it seems to indicate the touch part is broken as well so you may need to replace the full LCD assembly. There might be some for sale on the net, I have not searched. Note that fitting other components into the metal enclosure is not trivial, because you never get an exact size replacement part.