...
These "low ESR" electrolytic capacitors are good as long as there need handle low frequencies but they can not do nearly anything in this frequency area. 4mm long, 0.25mm copper wire is around 2.5nH. ( 100MHz XL is around 1.6ohm) Now I ask what is low ESR capacitor real impedance with 100 to 200MHz.) How about PCB GND trace impedances with this freq?
(btw: I know Owon is now working for this)
or maybe DIY instructions of how to repair it?
(UPDATED)
Hooray. A simple solution is almost completely eliminated the "GND-noise" of the converter +5,5V in my version of the adapter board. Overall noise level dropped by nearly four times.
Most were noise from the circuit display.
Details tomorrow (ie today, Moscow time).
As suggested earlier, the important cause of failure in the topology switching powers.
The simplest solution to slightly reduce the gnd-noise converter +5.5V is a way of shortening the path length of the pulse current on copper coated PCB. To do this:
...
In my case, the noise from the converter +5.5V decreased by three to four times. But now was significant noise from the pulse backlight TFT circuits +8,6...9,5V.
By the way, I tried to disable backlight switching circuit and power the lights directly from the circuit +8.4 V. Brightness greatly reduced and therefore the oscilloscope was almost impossible to use, but the noise was almost no more.
Thank you Siri about this Diode turn. Good finding!
Can you show us an example of a trace from your files showing the ground noise before the mod and a similar trace now?
Da shum upal prilichno, no eto v komplekse so vsemi peredelkami.
Dumayu esli postavit' ferrit to mojno zemlu ne brosat' na pryamuyu. No korpus ne zakrivaetsia iz za ruchki, mojet prosto poprobovat' obmota' ekranom shleyf. No nujen skotch takoy.
Otot gorb na fotah v albome pochti ne vidno.
Hey guys,
I have a small problem with my SDS7102 and hope you can help me.
The problem is, that the Scope starts to hang-up after a while. The LED starts to get RED, the Owon support said that this means the battery is charging but i don't have one
I think it is a temperature or PSU problem (or both) because the supply Voltage seams to break down (Fan gets slower)
Just want to know if anyone of you knows anything about that and how to solve it or if the problem is new.
HW-Version is 710243XX
LAN-Port only, no VGA, no RS232
Hope someone can help me
@RF-LOOP
Now that you mentioned battery indicator, I have a question:
Would battery indicator showing slightly discharged battery when the battery itself is removed from the scope be a sign of PSU problems? How does the indicator work on this scope? Just measure the voltage? Or is it doing something smarter?
Has anyone used the trigger holdoff on the SDS7102? I tried to use it today, but it seems that it only increments by 100ns at a time. I turned the knob for a minute and only got to 1ms. How in the world am I supposed to get to something like 100ms without turning the knob for an hour and a half? It's supposed to go up to 10 seconds.