Siglent SDS1202X-E compensation issue (and other manufacturers ?)

[Performa01]

I can pick up the value, but I need to know the type of capacitor. NGO or COG

It has to be NP0 or C0G, these are the same.

More important would be the voltage rating, but I'd say anything should be fine since it has to be at the output of the 2nd attenuator and the voltage there cannot exceed 4V with a 400V input. So 50V should be fine.

[tautech]

I can pick up the value, but I need to know the type of capacitor. NGO or COG

It has to be NP0 or C0G, these are the same.

More important would be the voltage rating, but I'd say anything should be fine since it has to be at the output of the 2nd attenuator and the voltage there cannot exceed 4V with a 400V input. So 50V should be fine.

Yes, being 0603 size it will not likely be more than 50V rated.

We can check on this but we will not have an answer for maybe 24hrs.

[evgen.05]

Yes, being 0603 size it will not likely be more than 50V rated.

We can check on this but we will not have an answer for maybe 24hrs.

OK, it does not burn to me. I'll be wait.

[tautech]

Yes, being 0603 size it will not likely be more than 50V rated.

We can check on this but we will not have an answer for maybe 24hrs.

OK, it does not burn to me. I'll be wait.

Email requesting the cap spec sent to Siglent. Now we wait.

[evgen.05]

Email requesting the cap spec sent to Siglent. Now we wait.

Thanks a lot!

[rf-loop]

I keep asking about your connection type to signal source as it must be a BNC cable not probe.
I look back through your posts and you do not make it clear that a BNC cable was used.
Please confirm you used BNC cable.

On one scope I corrected no adjustment was necessary for one channel as just the addition of the cap corrected the non-compensation. Usually any adjustment if needed is quite small.
If you are having trouble with one channel please check your work is very clean and the solder joint is good and there is no rework contamination of the surrounding area (flux residue or solder balls).
Good magnification and good light is necessary for careful inspection.

Did Welectron send you the caps ?
Did he get them from Siglent ?

Just to the right of the trimmers is CB105, the position missing the cap for ch1.

Yes, connected through the BNC cable when i've trimmed second time. Nothing is changed.
CB105 is missing(in 1st channel), You're right. In second channel this cap is present. That's the problem. Do You know what type of cap must be there?
Got this caps from China. Maybe from Siglent. There is no signature on mail and Siglent nothing told me about that

Do this "caps" mean that you get one capacitor or two capacitors?
If you get only one, who hell have made this work for sending this without brain.

So, first you tell that you can not get good result after rework but now you tell that capacitor CA105 is still missing. What a mess.

Capacitor type(s) (and many other things) is also told in this thread many times. Is it so that you first do and after then think and read. This is wrong order.
Also this Siglent rework instruction tell recommended capacitors. You have not read it?

Also example here.
https://www.eevblog.com/forum/testgear/siglent-sds1202x-e-compensation-issue/msg1335539/#msg1335539


and in Siglent rework instructions:

Solder a 4 pF/3.9 pF 1206 (3216 in metric) 500V C0G (NP0) capacitor on the red circle position in Figure 1 in each channel.
Recommended part #:
1206CG4R0C501NT?fenghua?
1206CG3R9C501NT?fenghua?
CC1206CRNPOBBN3R9 (yageo)
VJ1206A3R9CXLT (vishay)
VJ1206A3R9CXET (vishay)

[tautech]

@ rf-loop
See reply #247 and png.

C*115 is missing. We do not know why.

[evgen.05]

Do this "caps" mean that you get one capacitor or two capacitors?
If you get only one, who hell have made this work for sending this without brain.

So, first you tell that you can not get good result after rework but now you tell that capacitor CA105 is still missing. What a mess.

Capacitor type(s) (and many other things) is also told in this thread many times. Is it so that you first do and after then think and read. This is wrong order.
Also this Siglent rework instruction tell recommended capacitors. You have not read it?

Also example here.
https://www.eevblog.com/forum/testgear/siglent-sds1202x-e-compensation-issue/msg1335539/#msg1335539


and in Siglent rework instructions:

Solder a 4 pF/3.9 pF 1206 (3216 in metric) 500V C0G (NP0) capacitor on the red circle position in Figure 1 in each channel.
Recommended part #:
1206CG4R0C501NT?fenghua?
1206CG3R9C501NT?fenghua?
CC1206CRNPOBBN3R9 (yageo)
VJ1206A3R9CXLT (vishay)
VJ1206A3R9CXET (vishay)

Sorry i was wrong. Not CA105, CA115 is missing in first channel.

[rf-loop]

@ rf-loop
See reply #247 and png.

C*115 is missing. We do not know why.

OMG. Now I see this. How this is possible and how this have passed in quality control and factory calibration. Missing is not very extremely strange but how this scope pass factory control and calibration.
 

[tautech]

Email requesting the cap spec sent to Siglent. Now we wait.

Thanks a lot!

VC3 and VC4 have ~30 pF adjustment range and with C*115 in parallel I measure ~18-48 pF.
My SMD tweezers checked against the 4 pF caps Siglent sent me reads ~4 pF high.

So my best guess for C*115 value is 12-18 pF with seemingly enough adjustment in VC3 and VC4 to cover any of my measurement errors but no allowance for minimum VC* value.
So 12-18 pF will be max value for C*115.

C*115 removal and retest will the only way to get a closer value.

No reply from Siglent yet.

[evgen.05]

Email requesting the cap spec sent to Siglent. Now we wait.

Thanks a lot!

VC3 and VC4 have ~30 pF adjustment range and with C*115 in parallel I measure ~18-48 pF.
My SMD tweezers checked against the 4 pF caps Siglent sent me reads ~4 pF high.

So my best guess for C*115 value is 12-18 pF with seemingly enough adjustment in VC3 and VC4 to cover any of my measurement errors but no allowance for minimum VC* value.
So 12-18 pF will be max value for C*115.

C*115 removal and retest will the only way to get a closer value.

No reply from Siglent yet.

Thank You! What You think about voltage? 50V caps will enough?

[tautech]

Email requesting the cap spec sent to Siglent. Now we wait.

Thanks a lot!

VC3 and VC4 have ~30 pF adjustment range and with C*115 in parallel I measure ~18-48 pF.
My SMD tweezers checked against the 4 pF caps Siglent sent me reads ~4 pF high.

So my best guess for C*115 value is 12-18 pF with seemingly enough adjustment in VC3 and VC4 to cover any of my measurement errors but no allowance for minimum VC* value.
So 12-18 pF will be max value for C*115.

C*115 removal and retest will the only way to get a closer value.

No reply from Siglent yet.

Thank You! What You think about voltage? 50V caps will enough?

I think it will be like Performa01 said but a quick look for 0603 COG (NPO) shows many are rated @ 100V.
https://nz.rs-online.com/web/c/passive-components/capacitors/ceramic-multilayer-capacitors/?applied-dimensions=4294789462,4292094733,4294519026

To be more confident that a cap will meet spec I would use 100V NPO. You can easy try some test to see the voltage across the cap with a 1x input and a DC supply and step through V/div. Take care not to create a short while making this measurement. Be sure to add a good safety factor when selecting the cap voltage.
Good luck.

[evgen.05]

I think that is all done.

[tautech]

I think that is all done.

I would hope for much much better.

I have just finished reassembling the unit I posted screenshots from yesterday, it is just warming up before a Self Cal and after I will post some screenshots in ~30 mins.
Stand by.

BTW, what value did you install for C*115 ?

[evgen.05]

Installed 22pf 50V. - only that i found in my table. I think 20pf will be better. I've made an order in shop 20pf 100V NPO. Through couple weeks it will arrive and i replace it

in attachment - after 40min warming.

[tautech]

The flat top is good but the top of the rising edge can be much better.

These screenshots are the 1.2 and 1.22V/div  either side of the relay switching between ranges where the compensation issue is most visible to users.
Probe Cal output, 10x probe

1.2V/div


1.22V/div

[evgen.05]

10x probe 1kHz.

[tautech]

Thanks to Siglent for this:

The specification of capacitance is 0603 8pF +0.25pF 50V C0G for C*115

 

[evgen.05]

Thank Siglent for this:

The specification of capacitance is 0603 8pF +0.25pF 50V C0G for C*115

 

well, it's parallel to trimmer cap. His capacitance is enough for trimming. 22pF in my case is good too. Now looking for 0603 8pf - in our shops - i can buy them not lower than 12000pcs. Price for them - half price of oscilloscope. I'll replace on 20pf. It will be good.

[illusive]

Just received my scope from welectron. Im very satisfied with their service, contacted them to request the BB serial number model and they happily helped. The scope itself has no problem with compensation as expected.

[wakawakawaka]

I ordered this scope when it first released. I'm glad I looked around online, cause I thought I was crazy. I've sent siglent an email requesting the caps now.

[pilor001]

Greetings !!!!!!

So all in all, the bug has been eliminated ? 

Any comparison with pics before and after ?

All units are shipped out with this upgrade in place ? 



Regards, Akos

[tautech]

Greetings !!!!!!

So all in all, the bug has been eliminated ? 

Any comparison with pics before and after ?

All units are shipped out with this upgrade in place ? 

See reply #138.

https://www.eevblog.com/forum/testgear/siglent-sds1202x-e-compensation-issue/msg1348538/#msg1348538

[pilor001]

 

Copy that !

Hopefully it got implemented already to EU stocks... so when I order one here it will come revised.

 

[Welectron]

Hopefully it got implemented already to EU stocks... so when I order one here it will come revised.

This depends on the seller and how old his stock is. The goods units are shipping from Siglent since several weeks, but it takes time until warehouse stock has cleared.
We have the fixed version on stock, be sure to leave us a message during checkout.