• Kenny

    Hi there,
    A very nice article. You’ve inspired me to upgrade my MC500, MC 500 mkii and my MC50 mk1.
    I ordered the new oled displays and soldered them in. They seem to be working okay but i have noticed that some of the screens aren’t appearing: ‘Insert disk’ and so on.
    There are an extra 2 pcb holes in the new board, so 16 instead of 14 on the old one.
    I started the wiring from the bottom holes and left 15 & 16 empty.
    Should i have started at the top? I’m reluctant to resolder everything again.
    Many thanks

    January 11, 2021
    • Paul

      Did you ever get it figured out? I want to do that to mine.

      January 27, 2021
    • amsynths

      Hi, most 20×2 OLED’s just have 14 pins but Pins 15 and 16 should not be used as they are the backlight power to an LCD and were used on the original LCD. Let me know what model of OLED you used and I can double check. The connection is Pin 1 to 14. If you have OLED displaying characters then the connection is good.

      January 27, 2021
  • Paul Lanctot

    Cool. The one I’m looking at has 16 pins, and the original mc500 one has 14. In my unit the 2 wires that go to the transformer come off the other side of the original lcd.

    I’m looking at NHD-0220DZ-FSW-FBW.

    So just put pin one to pin one and the rest in order until 14, and leave the 15, 16 empty?



    January 28, 2021
  • Paul


    So just don’t hook up pins 15 and 16 on this? Thanks.

    January 28, 2021
  • Kenny

    Many thanks for all your replies, very helpful.
    The screens I used are
    model No: NHD=0220DZW-AB5
    From Mouser Electronics, Inc.

    January 29, 2021
    • Paul Lanctot

      I’m getting ready to try NHD-0220DZ-NSW-BBW and NHD-0220DZ-FSW-FBW will let you know,what happens

      February 09, 2021
    • Paul Lanctot

      Well I just tried mine and I get nothing on the screen at all on power up. I used pins 1-14.
      Reading 5 volts at pin 2 of the display board. The weird part is that pin one of the display connects to pin 14 of the connector on the main board, but looking at the schematic it made sense to me.
      The data sheet for the display says pins 15 and 16 are power for the backlight- pin 15 needs 5v , pin 16 to ground. So maybe I’ll try that , because the 5volts to pin 2 is for data power, according to the data sheet.

      February 11, 2021
  • Paul Lanctot

    I just tried again with NHD-0220DZW-AB5 – connected pin 3- ( contrast) even though it says it’s not used. the display is working but I have the same problem with “ insert disk “ screen not coming up- I have not yet disabled the transformer that fed the old backlight.

    February 16, 2021
  • Riva Lima

    Great job… What the type of rotary encoder?

    July 07, 2021
  • Pierre

    Hi Congratulations on your willingness to share your experiences with Roland Mc 500, I would like to ask you for advice, I recently bought mc500 even if in the past I had mkII, now I don’t have the sys disk and I don’t even have floppy on pc, i would like to bulk data via midi connection, do you think it is possible if possible
    how do you advise me to achieve my goal.
    Thanks again

    August 17, 2021
  • Krystian

    Thanks for this post.

    So can you just get a standard Gotek drive and slot it in instead of the disk drive (with boot software etc on a USB)?

    October 29, 2021
    • amsynths

      Hi, you will need to configure the Gotek as a standard floppy drive replacement with the correct ID(0) and then its a straight swap.

      November 01, 2021
    • Krystian

      Thanks for your help.

      One more question (as you seem to be the only person who knows about this stuff on the internet!) – my MC-500 (it’s not a MKII) uses MRC-500 ‘version 1.10’.

      Is that something in between the original MRC software and ‘Super MRC’?

      I don’t think it’s Super MRC because once it loads from the floppy disk, it doesn’t need to load anything again (I heard that because of smaller memory of MC-500s vs the MKIIs, it would otherwise need to load from the floppy disk each time you used some function).

      Disk drive works fine at the moment and I have a few, but I may just buy a generic floppy disk drive emulator to have in case I need it, as I heard they are the same as the Gotek ones.

      Thanks again!

      November 01, 2021
      • amsynths

        No there is no other software version just the MRC and Super MRC. MC500 Mk1’s could be hardware upgraded to a Mk2 but they usually have stickers on them for the new functions. Enjoy!

        November 08, 2021
  • Yeah it’s strange, as it shows up as version 1.10 when I load it. I really like my MC-500 – such a great unit, just finished my first song fully sequenced using it: https://www.youtube.com/watch?v=UL5gZzoKJmU

    December 13, 2021
  • Mario

    MRD-500 Rhythm Track Disk

    Hi Would anyone out there know how to put the .sng files on a USB. As the Gotek only reads images.
    Thank you in advance

    April 19, 2022
  • Thank you for this article. great job!

    October 11, 2022
  • Thank you for sharing, very helpful article.

    November 06, 2023
  • “MC-500’s can not be easily upgraded to 786 KB of memory. The processor and RAM need swapping out and the extra address line added. Roland did offer the OM-500 upgrade, which must be a main PCB swap, and the resulting sequencer is called a MC-500B by Roland..” Has anyone worked out the extra address lines needed to piggy back the RAM? The CPU swap out is pin-for-pin so that’s relatively easy. The new EPROM is also cheap / simple. So upgrading from 256K to 768K is just a matter of piggy-backing 3 x D41256C chips and wiring off the extra address lines.. (Not pretty but do-able!).

    Anyone seen a MC-500 Mk2 to copy?

    March 10, 2024
  • squishy

    Re: ERROR 3

    I recently bought a MC500. It had no OS disk. I have no USB-FDD.
    I managed to get an OS diskette from a very obliging past synth-buyer = luck!.
    However I get this ‘error 3.’
    The manual refers to this error 3 as a ‘disk initialisation’ issue.
    I found one reference online to this: > Error 3 I/O indicates the system disk (floppy) is damaged or has not been initialized yet.

    You wrote: The diskette must be pre-formatted by the MC-300/500/50.
    So, is this format, the same as disk initialisation?
    Should ONLY DS/DD disks be used?
    I am asking since I cannot do this myself and am reliant on the obliging past synth-buyer to create a new disk for me.

    April 22, 2024

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