Unfortunately, I haven't functional my scope. Pehaps some measurement to my circuit will help you.
Still, I am wait the AOZ1094 to arrived.
Carrington, the EMI shielding where you thinking to apply? Front or back of the screen and what dimensions we are need?From, is as glass, but with a conductive coating.
https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg279474/#msg279474
I see, you are thinking to use it like a glass in front of tft display. I saw that you have done the same question to the Rigol DS2072 thread.
I''ll doing a search about this.
Hi TomC!
I forgot to show the general duty cycle and to write about the large peaks in the last post, so I updated it. Basically, the peaks are still there and they don't seem to be related to MC's operation. Could the TL431 be producing them somehow? Duty-cycle is close to rf-loop's.
Maybe 3 metal-film resistors in parallel, each with nominal value of 1.8 ohm? That would be pretty close.OK, I'm obviously too tired to calculate...
By the way, can someone to take a capture how display the scope a 40mVpp 100kHz sine wave at 1ms/div 10mV/div or 5mV/div? One channel and 10M memory depth. Please with scope with not gnd noise. Is there any aliasing?
By the way, can someone to take a capture how display the scope a 40mVpp 100kHz sine wave at 1ms/div 10mV/div or 5mV/div? One channel and 10M memory depth. Please with scope with not gnd noise. Is there any aliasing?
The whole story held to Rigol DS2072 thread that one member (Galaxyrise) ask the rest member how is it to the other scopes becouse the Rigol High-Res mode is so different from what his expected.
...
TomC, sorry for this adding effort but at the first yours capture "1ms-Div.png" the sampling is 500MS not 1GS.
Can you see what it is happening? I want to upload this capture to the thread of Rigol.
First one thing I've noticed: With new regulator, both regulator and coil run much cooler than before. Previously I couldn't hold my finger next to them because of heat. Now they're just very hot, but not burning hot.
I did some scoping on the timing capacitor itself and its waveform is very noisy and jittery. According to the scope's frequency measurement, the frequency is always changing. It's usually around 48 kHz, but can go as high as 60 kHz sometimes. I'm attaching image with infinite persistence. Another image which I found interesting is when I probes the pin 2 and pin 3 at the same time. It seems that there are huge bursts of noise on pin 3 when pin 2 is high.
Should I try changing the capacitor? It seems like a polyester capacitor to me, but from what I heard they should be pretty good.
I can easily obtain ceramic multilayer capacitors of same capacitance and tolerance with NP0 dielectric and try with them, to see if it's the capacitor.
AndrejaKo, I need to look at these waveforms in more detail, they seem very interesting. Right now I have to run a 2 or 3 hour errand, but I'll give you more feedback when I come back. If you have a similar capacitor go ahead and change it, it'll be one less component to worry about. The capacitor's you propose should be good enough at least for a test.
I changed the timing capacitor and there's more or less no difference, so I think that we can safely rule it out as the source of the problem.
I changed the timing capacitor and there's more or less no difference, so I think that we can safely rule it out as the source of the problem.Disconnect the circuit that generates the -7.6v, now use five 1.5v batt. in series or your linear PSU (better batt.), connecting the negative terminal to -7.6v point and the positive terminal to gnd, now turn on the oscilloscope using only your lithium battery. Continue appear those spikes?
Note: If you use your PSU don't dare to power it using the network (220V).
Do not worry, the oscilloscope "up" successfully even without the -7.6V. Although as is logical the input stage will not respond properly.
It not will be destroyed, I made the test on mine. Note that the -7.6v only power to the analog input stage through a LDO (7905).
After moving the scope to my no electronics room, the large peaks disappeared. Now to refresh readers' memory, with the MC running and the scope in my no electronics room, I still had the peaks, so at least some of those peaks had to be coming from somewhere near the MC.
Anyway, in the no electronics room, I only got the smaller peaks I mentioned few times before. My guess is that they would be coming from the adapter board itself. They are illustrated in the last two images.
After moving the scope to my no electronics room, the large peaks disappeared. Now to refresh readers' memory, with the MC running and the scope in my no electronics room, I still had the peaks, so at least some of those peaks had to be coming from somewhere near the MC.
I agree with your conclusion that this noise is very likely originating from more than one source. I would recommend that from now on any further tests be conducted in the no electronics room.
@Carrington Yes, the test without the MC was done in the no electronics room. In future, I'll do all tests there. The adapter board is the standard 3.0 version board. So far, I did not make any modifications to the board itself, other than attaching ferrites to the cables. Also thanks for the encouragement to test this with batteries only. I needed it.