Thursday, March 22, 2012

new strobe lamp

the original neon bulb of the SP10MKII was confirmed dead.

I removed the original neon bulb and tried to make an alternative.
the strobe circuit of the SP10MKII is "flashing" at a frequency of about 105Hz at 33 1/3 rpm and about 142Hz at 45 rpm.
using LED(s) to replace the neon lamp is easy and simple.
I've made a small PCB that use the original neon mounting holes.

in order to keep it compact, SMD LEDs were used (size 0805), there is a total of three LEDs driven by a small transistor. everything is powered by a single 5V DC (from the SP10KII control board)

it looks cool, isn't it?

everything just fit to the original neon bulb mount and it also runs cooler.

yeah, here we go, the orange LEDs looks pretty good.

I can remove the 140V DC supply section now as it's only used to power the neon blub which is no longer used anymore.


  1. Hi there! Marvellous solution to the common dead-lamp problem in the SP-10. Would you be willing to share the circuit diagram please as I'd like to try this with my SP-10. Is it OK to use the control 5V line - I'm sure I remember someone on the 'net mentioning that adding LEDs to the 5v line could increase noise on that line?

    Many thanks! Great site!

    - John

    1. Thanks John!

      I didn't have any negative experience using the 5V line from the control section.

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  3. Hi - sorry to disturb you again!

    Would you be able to let me know (or email me) the resistor values you used for this please, as I'd like to build my own LED board for my SP10. The only difference being I'd be using through hole components, and standard 3mm amber LEDs though. Unfortunately I lack the knowledge to work these values out myself, but am good at following instructions ;)

    I have my SP-10 Mk.2 working nicely now, but just need to address the LED issue.

    Thank you.


    1. Hi John,

      I assume your amber LED has a forward voltage of about 2V and current of 10ma, then a 300 ohm resistor is about right.

  4. Thanks so much - that's great. Much appreciated :)