DSO 5102P problems with channel 2

TDave007

Hi.
I bought this oscilloscope last week and I have a problem with channel 2.
When I try to calibrate the probe with 5V@1Khz point test, I cant get a square wave in channel 2, it's imposible.
Then, I get a strong signal when the probe is disconnected when it must be a line.

I have recorded two videos to the seller can watch the problem, but he ignores my messages.
The videos can be watched in https://www.youtube.com/watch?v=AFzqXdi8SWU and https://www.youtube.com/watch?v=iNmAjxmjIkc
I dont know if it's a sofware / firmware problem or a hardware problem.
I need a solution about this.
Thanks

amy

Sir, could you solder?

TDave007

Of course, I can solder without problems. Any sugestion?

amy

TDave007 replied at 2016-11-24 06:57
Of course, I can solder without problems. Any sugestion?

Sir, please try to replace the five components corresponding to the channel 2 in th epicture.

If not, contact your seller to repair it.

TDave007

My friend, thanks. I have received and reemplaced the elements you say me, but the problem continue. I have tested it with another oscilloscope and I have found the place where the signal is distorted, the signal is perfect square wave and when the signal passes through the element, it's distored how I showed in the first message. I dont know what is it, I hope you can say me what is it to try repair it.
Thanks for your help

TDave007

Hi again. I have got a schematics about this oscilloscope and I have focuses the study about this error.
I think the component I have marked in the last message is a 330pF 50V SMD capacitor, but I think perhaps other component can be do this channel works bad.
In the TP201 I can get a perfect squarewave 1Khz from the calibration point, but when the signal passes to the "red circle" in the image, this is the zone where the signal is disturb.
Analizing the schematics, there are three ways to the signal arrives this zone: through the SMD capacitor, the OP AD8510 or the BAV99 switch diode.
I have to test the TP202 to be sure the photomos relay AQY280S woks well, but yesterday I hadn't more time to do it.

According to your experience, could you tell me which component might be failing?

Thank you very very much.

TDave007

Hi again. I would like if you can confirm me if this component B7A (AD8510 in last image) is really AD8510 or another amp op. I hope to can repair it someday. I can get a squarewave in TP202, so I think the problem is B7A or 330pF capacitor. What do you think? Thanks a lot my friend.

amy

The component B7A is AD8510ARMZ-REEL. Please replace it to try.

TDave007

Thanks amy. I only can get the amp op AD8510, no AD8510ARMZ-REEL. I am searching about this model but all the datasheets of AD8510ARMZ-REEL link to AD8510 version, perhaps the same?. Is it sure the replace with AD8510? Both are MSOP8
Thanks a lot my friend.

amy

Please refer to this link: https://www.amazon.com/5PCS-AD85 ... rds=AD8510ARMZ-REEL