[sdiy] Glowing diode on Casio CT-510 analog board?

Adam (synthDIY) synthdiy at adambaby.com
Tue May 23 04:16:59 CEST 2023

I don't know much about the CT-510
I have an MT400 that has analogue drum sounds and a VCF, along with the usual square wave synthesis of many Casios around that time. 
The CZ-230s has PCM drum sounds and Phase Distortion synthesis doesn't it? So there wouldn't be much "analogue" on that board you'd think.

What's "NLC"?


> On 23 May 2023, at 11:26 am, Benjamin Tremblay via Synth-diy <synth-diy at synth-diy.org> wrote:
> This topic could easily split two ways.
> 1) the CT-510 is my practice dummy to get me in shape to fix the analog board on a Casio CZ-230s, a more interesting specimen.
> 2) I have never built any NLC projects but spent an afternoon daydreaming about the LED-controlled Bong0 module. The idea of using glowy things to generate sound is intriguing. I love the rubbery flabby sound those modules make.
> Benjamin Tremblay
>> On May 22, 2023, at 9:03 PM, Benjamin Tremblay <btremblay at me.com> wrote:
>> Here it is.
>> <image0.jpeg>
>> Benjamin Tremblay
>>> On May 22, 2023, at 8:41 PM, Benjamin Tremblay <btremblay at me.com> wrote:
>>> Sorry if this is way way way off topic. I’m trying to fix this Casiotone keyboard and there are no schematics. The power supply seems to be putting out around 4 volts. The logic board runs but the 4558, 4066, and power amplifiers seem inert. 
>>> I’m trying to trace the power supply. Unlike most Casios from the 80s, the 5 volt regulator is just a zener diode, not a 7805. There’s one more non-zener diode on the board, and it’s faintly glowing red (!)
>>> I know all diodes emit radiation when they are operating, but this one has such and led-red color.
>>> Were such diodes ever used to indicate an overload on the board? I was more interested in fluorescent hair gel than power supplies  when this keyboard was made. 
>>> <image2.jpeg>
>>> (Lower left corner, a normal looking glass diode)
>>> Benjamin Tremblay
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