I would like to test the scope without the Owon PSU, but I am thinking how manipulate the trigger output of the flat ribbon.
How is the right way to be done?
Sure, I need two independent voltages by -7.6V and 8.4V - this is easy I have the appropriate psu - but the ac trigger output?
Well done, TomC. I'll wait for your result.
I would like to test the scope without the Owon PSU, but I am thinking how manipulate the trigger output of the flat ribbon.
How is the right way to be done?
Sure, I need two independent voltages by -7.6V and 8.4V - this is easy I have the appropriate psu - but the ac trigger output?
When dismantle (unfit) my scope to applying shielding, I found the time to take some photos to the others boards.
Here are with the full resolution, only an amount of compression for smaller files.
The photos are from the two buttons boards, the one is L schema of buttons (H1..H5 horizontal and F1..menu off vertical) the other is main menu buttons. Also there are photos from the mainboard, both of sides.
After that, I removed the current sense resistor and those noise bursts I had after switching are now gone. I'm thinking of putting a picofarad range capacitor in parallel with the resistor, since I'd like to have it there in case of overcurrent situation.
Interesting thing is that duty cycle remains erratic even with the current resistor removed. Switching noise still remains.
Andrejako,
I would try adding an electrolytic capacitor at or near the MC's VCC pin. Just in case the 8.4V don't have enough filtering at that point.
Your "motherboard" is very different to mine, and my ADC is from National.
I added a 1 mF low ESR aluminium electrolytic capacitor directly to the hole where the current sense resistor connected to Vcc pin and the second lead to ground next to some exposed resistors. It made no improvement.
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@lemon
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On the bright side, of all this PSU noise, at least I have an entertaining way of learning a bit more advanced electronics. My friends spend their time tuning their Yugos, while I spend my time tuning my scope
Your "motherboard" is very different to mine, and my ADC is from National.
Functionally exactly same. "RuiFeng" MXT2002 is functionally clone of ADC08D500.
There can use both. (but physically not directly pin-pin becouse "RuiFeng" add extra (n.c.) pins to every corner)
MXT2001 is 2x1GSa/s (SDS8102) and MXT2002 is 2x500MSa/s (SDS7102).
Owon have used "RuiFeng" and other manufacturers ADC08D500 in SDS7102
Perhaps also some Rigol use "RuiFeng" ADC's.
Page from MXT "User manual"
and perhaps this picture is from MXT factory.
... there are some bridges to the left and up side of the Chrontel chip. Is that normal? Also, I must to examine the C146 at the left of this chip, in photo seems like to be damaged or to has a bad soldier.
This (lemon version) more low noise and higher BW (and less power consumpting) front end (before ADC) have been also quite long time.
This (lemon version) more low noise and higher BW (and less power consumpting) front end (before ADC) have been also quite long time.rf-loop then what are the main differences between the Lemon main board and mine?
Thanks.
Lemon, could you try the shield case without the buttons board inside?
Thanks.
Detail_2:
Broken Inductance (It came broken from the factory).
This DC/DC converter power directly the whole DAC, analog and digital, any filter between.
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Edit: Lemon, I just noticed that mine does not have that plastic (red), and therefore makes contact with the gnd of Button_2F board.