LCD and LED flickering


I have just registered and I have also read some of the older topics with similar problems but I couldn’t really find an answer to my problem - so maybe you could help me =)

I have completely assembled my Shruthi-1 (bought in January) and though I didn’t have much time to use it for a longer period everything seemed fine until now. But yesterday some strange glitches began to occur:

  • after plugging in the power supply the LCD sometimes starts to flicker
  • this flickering only affects the symbols on the LCD, the brightness does not change (or just very slightly)
  • the flickering starts and stops over time, sometimes it stops completely when the Shruthi runs for a longer time
  • sometimes the LEDs start flickering too
  • after the flickering the values on the LCD respond very slowly - I change a value and the displayed value blurs
  • when sending a sustained MIDI note to the Shruthi the flickering sometimes also affects the sound (resulting in a short crackling)

It almost looks a bit as if the Shruthi is losing power for a short time over and over again - but the problem seems to affect mainly the display elements and not the sound.

Any suggestions where to start looking for the source of the problem? Or maybe someone already had that issue and solved it? Unfortunately the synth is already completely assembled so disassembling will be a bit annoying .

Thanks in advance! =)

a) check the voltage (stability) of the power supply you are using
b) check the solder joints of the power supply chain on the filter board
c) check the voltage that is delivered to the control board via the “sandwich” connector, could be that the connection between boards is imperfect, try to use the cables that come with the kit
d) try another power supply

Oh yeah, c) definately needs disassembling, so try the others first if you want to avoid that.

Hey! Thanks for the quick response!

Ok, I will try a different power supply, check the connection between the boards and see if there is a glitch in the power supply chain of the filter board (although I tested it during the assembly and it worked perfectly fine). My worst fear would be a bad solder joint somewhere on one of the boards - I guess such a problem would be really hard to locate =/

I’ll post my progress as soon as possible.

Back at home I started my Shruthi and just kept the power on for quite a time to see what would happen. Surprisingly the flickering is gone.

Since the glitch seems to occur just sporadically I’m not really sure if measuring the power chain would provide much results…

Is there a possibility that the described flickering is somehow connected to the operating time or temperature of the unit?

At the time I was tracing a bug in the MIDI handling code last june I let some gremlins test running entire nights, so I don’t think there’s something fatal happening after X hours of work…

Sorry, but no offence meant, pichenettes. I am really enthusiastic about how well done everything about the Shruthi is. My question about problems with the heat refered to my own (completely inexperienced) soldering skills :wink:

Is there a possibility that imperfect soldering joints e.g. break up due to board tension and re-merge because of the operating temperature?

By the way, I activated my Shruthi for a short time today and again there was no flickering. Really strange…