Struggle to tune the scope probes that come with Analog Discovery 2

[tomko]

Hi,

Analog Discovery 2 is my first ever oscilloscope and I plan to use it with my Arduino to explore the world of electronics.

I recently purchased a Analog Discovery 2 along with the BNC adapter. I tried to tune the probes (P6100) that come with the ultimate AD2 bundle but I can't seem to be able to get a good square wave. It is always under compensated. I tried out both channels on the adapter, Channel 2 is worth than Channel 1.

I attached a few photos for your information. The red one is from Channel 1 while the blue one is from Channel 2. I also attach a photo on how the probe is connected to Channel 1. In all cases, the probes are connected to W1 coming out of the AD2 (see the Connections.png) and is outputting a 1KHz square wave with 5V output. The probes are set to x10 and the attenuations are also set to x10. And Channel 1 on the BNC board is set to AC coupling. 

My computer is a MacBook Pro 2018 and the WaveForms is version 3.17.1 64-bit Qt5.12.9 MacOS 10.16 Qt5.12.9.

Am I using the incorrect method to tune the probes? Or could it be faulty probes?

Any advices are greatly appreciated!

Kind regards,

Tom

Edited January 20, 2022 by tomko
Extra information on the probes

[sarming]

I would use DC coupling, but other than this your approach looks good.

You might be able to get replacement probes:

I am having the same issue with recently purchased Sensepeek SP200 probes. According to their manual they have a compensation range of 15-45pF - which should be more than enough for the 24pF given in the AD2 specs. Although this thread claims the input capacitance is 43pF:

Since it is my only scope, I have no way of checking whether it's the AD2 or the probes that are out of spec. And threads like these make me wary of complaining the probes to the distributor:

 

Anyway, you are at least in the lucky position to have an officially supported probe :)

[tomko]

Thanks sarming. I managed to order a new pair from Amazon which arrived this evening. And I was able to tune the newly purchased probes to give a perfect square wave. So I guess the probes that came with the bundle are faulty. I will email digikey support to get a replacement pair.

 

[Cristian.Fatu]

Hello,

When contacting Digikey you can inform them that Digilent approves this replacement.

Best Regards,

Cristian Fatu

[tomko]

Thanks!

[tomko]

Contacted Digikey - unfortunately they are not able to send me a pair of probes since my probes came within the Ultimate AD2 Bundle. They are happy to send me a replacement for the whole bundle provided I returned the bundle I received. Since I am based in the UK, it seems a lot of effects with all the packaging and shipping just to get a replacement probes.

Can Diligent send me a pair? If not, then I will source one from Amazon locally.

[Cristian.Fatu]

I have requested replacement for your probes.

I was informed that replacement probes were send to you. Tell me if you are not receiving them.

Edited February 1, 2022 by Cristian.Fatu

[tomko]

@Cristian.Fatu I received the replacement probes today. Many thanks.

[Cristian.Fatu]

You are welcome.

It is good that things are settled now.

[tomko]

Hi @Cristian.Fatu

I tried to tune the 2 new probes and I am afraid that they are still having the same issue, both still under compensate. One is a bit better than the other. I have bought a pair locally from https://www.amazon.co.uk/gp/product/B088YMNJ6V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1. I believe they are of the similar type. They can be tuned to under or over compensate so I can get them to give a good square wave.

I attached 3 screenshots, New probe 1, New probe 2 and Locally sourced probe. For the new probes, you can see the square wave is still under compensated. In all cases, I am outputting the square wave from the waveform 1 in the BNC adaptor into Scope 1.

Are you able to get a pair tested before sending to me?

Many thanks

 

 

[Cristian.Fatu]

A new pair of probes were sent to you on 2/20.

[tomko]

Hi @Cristian.Fatu

Many thanks - I received them 2 days ago and am now able to adjust the square waves accordingly.

Kind regards,

Tom

[Cristian.Fatu]

You are welcome. Glad to see that this is finally solved.

Best Regards,

Cristian