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Electronics => Projects, Designs, and Technical Stuff => Topic started by: Emi on March 10, 2016, 06:42:01 am

Title: Some tweaks on DS2072A, backlight and noise.
Post by: Emi on March 10, 2016, 06:42:01 am
Hi. .
I'm very happy to be an owner of this great scope ( full option hacked) but I'd  like  some improvements. .

-Im a bit disappointed can't dim panel  backlight. .it's too bright for me ! trace and grid  dims but bl not? Why?  8) is there a way to mod this?  ( even opening/cutting/ soldering something :) )
-Can i improve  input noise shielding cables or chips?
  Its always  about 2mV pp..really too much !
  i think psu wires could be the cause...
Should i put ferrite cores everywhere?

Can You give me some hints?  ;)
Title: Re: Some tweaks on DS2072A, backlight and noise.
Post by: ElektronikLabor on March 10, 2016, 09:53:18 am
-Im a bit disappointed can't dim panel  backlight. .it's too bright for me ! trace and grid  dims but bl not? Why?  8) is there a way to mod this?  ( even opening/cutting/ soldering something :) )
You could use an 555 timer as an pwm; the circuit would be quite simple and small. Then you could control the backlight by a potentiometer; but you have to drill a hole for the pot ;)
It would be cool, if the scope automatically dims the screen in dependence on the ambient light, like any mobile phones already does ;) For that you need some kind of photosensor which is mounted on the outside of the scope and a circuitry which convert the signal of the sensor to a PWM.

If you don't need the option for adjusting the brightness after modding, it's even simpler.
1st possibility: The LEDs are driven by a voltage source with current limmiting resitsor(s); change the reistor(s) to a higher value.
2nd possibility (more unlikely): the LEDs are driven by a current source; change the sense resistor which adjusts the current value to a bigger one.

Can i improve  input noise shielding cables or chips?
Yes it could be possible, but for that you must know the source of the noise. If it would be easy I think Rigol did it already by themselves  ;)
If you think it'ss the wires, then you could check it by adding some noise on the wires (e.g. via a transformer) and watch if something changes.
Title: Re: Some tweaks on DS2072A, backlight and noise.
Post by: Emi on March 10, 2016, 10:26:36 am
Thanks  :-+
But let me know. ..
I thought BL was lamps. .not leds  :-[
Anyway your suggestions for 555 are cool (i've just put on a breadboard a similar circuit..with a fotoresistor sweeps the DC...) but i wouldn't add more  noise inside. ..
Is panel directly  feed from psu?
In this case a resistor o strong pot on the right wire could be perfect for me...but ..which wire? 

If only  electric schemes of this stuff were avaiable  ::)