1. Forum
  2. Usenet
  3. SCI.ELECTRONICS.REPAIR

  • Korg SDD-3300 update (success)

    From bitrex@21:1/5 to All on Thu Feb 20 10:56:37 2025
    I eventually got fed up and took a gamble replacing the intermittent
    EL-backlit LCD screen with a modern 20x2 from Crystalfontz:

    <https://www.crystalfontz.com/product/cfah2002a1tmijt-20x2-character-display-module>

    I'd seen reports that it's finicky about aftermarket displays but this
    one fired up just fine, and the problem hasn't recurred. The old display
    panel seemed very finicky about glitches on the +5 rail and I tried a
    lot of things but couldn't get it to work consistently, maybe the new EL backlight under it was interfering with it somehow, who knows...

    But in the process of mounting the new display I managed to crack part
    of the cheap brittle 40 y/o phenolic board and had to jumper some power
    lines to the meter LEDs, ugh...this thing had a lot of problems to begin
    with and like it was definitely built to a budget, stinky single-sided
    phenolic with jumpers and air wires everywhere, it's from 1987 but built
    like a piece of cheap 1970s home stereo equipment, with wobbly input
    jacks and controls mechanically secured only by the PCB.

    Kind of a PITA to work on, but it is almost fully digital with only a
    couple LM13700 and companders on VCA duty so there's not too much in the
    SM to adjust once it's running..

    The Sony digital reverb unit I have from a few years later (1991) is
    built like a piece of aerospace hardware by comparison. I've only seen a
    couple of these for sale domestically in the US over the years, seems
    like they didn't make too many and they were all screwed-up to begin
    with like this one was so I wouldn't be surprised if it was one of the
    few still in operating condition. Sounds nice, but I don't really want
    to deal with one again like this haha

    It does look cool all lit up. Uses an NEC variant of the Z80 at 12 MHz
    for brains.

    <https://imgur.com/a/fljL11u?>

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeff Layman@21:1/5 to bitrex on Thu Feb 20 18:43:17 2025
    On 20/02/2025 15:56, bitrex wrote:

    It does look cool all lit up. Uses an NEC variant of the Z80 at 12 MHz
    for brains.

    <https://imgur.com/a/fljL11u?>

    Good that you got it working, but if you want something "cool lit up",
    this link to a Philips EL6471 was posted today in uk.d-i-y <https://www.youtube.com/watch?v=C3_-2fUm6y0>. Those mercury arc
    rectifiers responding to the current drawn are something else,
    especially when the meter hits the end stop around 2.50!

    --
    Jeff

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to Jeff Layman on Thu Feb 20 16:20:02 2025
    On 2/20/2025 1:43 PM, Jeff Layman wrote:
    On 20/02/2025 15:56, bitrex wrote:

    It does look cool all lit up. Uses an NEC variant of the Z80 at 12 MHz
    for brains.

    <https://imgur.com/a/fljL11u?>

    Good that you got it working, but if you want something "cool lit up",
    this link to a Philips EL6471 was posted today in uk.d-i-y <https:// www.youtube.com/watch?v=C3_-2fUm6y0>. Those mercury arc rectifiers
    responding to the current drawn are something else, especially when the
    meter hits the end stop around 2.50!

    Truly a work of art of the "they don't make em like they used to" genre.
    It needs its own theme song (though toccata and fugue in D is already in
    the ballbpark...) Hell it needs its own national anthem.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeff Layman@21:1/5 to bitrex on Fri Feb 21 09:27:06 2025
    On 20/02/2025 21:20, bitrex wrote:
    On 2/20/2025 1:43 PM, Jeff Layman wrote:
    On 20/02/2025 15:56, bitrex wrote:

    It does look cool all lit up. Uses an NEC variant of the Z80 at 12 MHz
    for brains.

    <https://imgur.com/a/fljL11u?>

    Good that you got it working, but if you want something "cool lit up",
    this link to a Philips EL6471 was posted today in uk.d-i-y <https://
    www.youtube.com/watch?v=C3_-2fUm6y0>. Those mercury arc rectifiers
    responding to the current drawn are something else, especially when the
    meter hits the end stop around 2.50!

    Truly a work of art of the "they don't make em like they used to" genre.
    It needs its own theme song (though toccata and fugue in D is already in
    the ballbpark...) Hell it needs its own national anthem.

    Yep. The piece in the YouTube video is Widor's toccata from his symphony
    No.5. You wanted Bach? Be my guest... <https://www.youtube.com/watch?v=G7qMVYf85sM&t=186s>

    --
    Jeff

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)