Korg ESX-1 1.5a “chip” Fuse repair

By | May 23, 2010

Had to repair my ESX-1 today. I went to turn it on this morning and it would not power up. The symptoms are: Unit turns on; Yellow back light comes on; No text on the display; No Led lights. When you turn it back off the LCD’s Back-light turns off very slowly after you press the power button, as with lag. These are all very noticable. If your unit is doing these 5 things and nothing more, nothing less… then is it very likely you have a bad fuse. Once I googled the info up (I had read about it before), the repair took me about 30 minutes.

Apparently many of the early models off the Korg line had a 1.5a fuse on the board that often goes bad, they later replaced it with a stronger fuse. Many people bypass the fuse altogether in order to get their ESX-1’s (and EMX-1’s) working again since the fuse is not a typical one you can easily find. I bought my ESX-1 used off Ebay nearly 3 years ago and the problem did not occur until now. I do not leave my ESX-1 powered on when unattended because it can run pretty hot after awhile and here in Louisville we have alot of lightning/thunderstorms. It was not a storm or power spike that caused it to go out, Korg just chose a bad part on these early models. They used to repair them for free, but I believe that period has ended. You can always contact Korg Repair and ask if there is an authorized repair shop near you, or failing that you could send it in.

I do not recommend anyone else doing this repair unless they are confident about their precision/pcb soldering skills as the contact points are very small. However, if you insist on doing so (like I did), there is a helpful thread about doing this @ Korgforums. The pictures in it are poor quality though and there’s no mention of taking apart the ESX-1. I found a couple other pictures to assist me. Click them for larger views.

The first picture is one of the Fuse itself that needs to be replaced or bypassed, note that with a bypass like this once you know the rating needed for the fuse you could add a ratshack one in yourself inline (i did not). Note that the fuse is labeled ‘FUSE1’ and that its near the cluster of capacitors located on the right-hand side of the board:

This second picture is from a forum thread back in 2006 that I had to dig up off Archive.org. It shows the simple process of taking your ESX-1 apart. There are 14 total screws, 10 of which are 2.5mm HEX that hold the faceplate on and then 4 Philips head screws around the Tube section that hold the control panel to the body:

4 thoughts on “Korg ESX-1 1.5a “chip” Fuse repair

  1. Mechanoid

    Hello there, maybe somebody can help me, my esx-1 has an error. errorcode is: N_Initlz Error what means it, i think iam the only guy in the world who has this errorcode on the esx-1..what can i do ???? Plz help me

  2. Mo Keachie

    i have this exact error on my Emx. i bought it second hand and i have had it for 2 years now. i have heard that Korg will still replace the fuse for free, is this true?

  3. aaron m. Post author

    No, they stopped replacing the fuse for free quite awhile ago and it was only done through official korg repair centers. If I remember right from Korg forums (re a post by a ex Korg support worker) the last doing it was in the UK and IIRC.. they closed shop.

  4. Brad

    Hey My name is Brad and I also live in Louisville and I also have a Korg ESX-1 with the same issue. I was wondering if I could pay you to fix it or look at it?

    My email is

    or contact me on fb Brad Adams

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