SIGLENT SDS2xxxX Plus digital probe broken and misreading ? (pic) - Page 1
Forum section: electronics / testgear

author: jnz
author_rank: Frequent Contributor
timestamp: March 14, 2022, 11:19:09 pm
content: So... I just wasted 1/2 a day on this.Someone please explain what I have here!?Setting up and initial testing SPI from an STM32 to a deviceCS pin on Digital 4 / Yellow, labled CS/C1 analog is connected to the same point as CS/D4As expected.... the analog drops to ground for the start of the transmission, MISO, MOSI, CLK, all goodCS is...wrong.Added a different digital input Digital 0 / Black, labled CS2... and it shows like analog C1 as expectedUsing both digital grounds at different pointsThere is no setting for this right!? I can't calibrate the digital probes?I identified the problem to the SPL2016 adapter on G1/4. The adapter octopus seems to work fine on G2.I'm sure I'll contact Siglent, and swap it out, but it really burns a lot of trust in this thing! Is there a change I just made a stupid mistake?

author: tautech
author_rank: Super Contributor
timestamp: March 15, 2022, 12:26:31 am
content: Seems to be triggering on the rising edge overshoot when CS returns to Idle High.Check the correct idle state setting is applied in Decode and/or its Trigger settings.Suggested sanity check:Use normal edge triggering and set it to D4 falling edge which should shift the triggering to the start of CS.EditAdditional info:LA probe tip to LA Pci-e connector pad series resistance = 91.1khttps://www.eevblog.com/forum/testgear/diy-logic-analyzer-probe-and-pods-for-siglent-scopes/msg3522024/#msg3522024

author: jnz
author_rank: Frequent Contributor
timestamp: March 15, 2022, 01:34:50 am
content: Yea, I thought about it triggering on the overshoot too, and that is what it looks like, except, this is a 3V3 signal. But this line D4 didn’t show anything at all when touched to the cal square wave pins which is 0-5V iirc. So it’s not 3V4 and it’s not a zero issue. I have no idea what it’s doing.Thanks for the resistance number, I’ll check that tomorrow morning.

author: tautech
author_rank: Super Contributor
timestamp: March 15, 2022, 02:15:37 am
content: Quote from: jnz on March 15, 2022, 01:34:50 amThat's about the only other thing I can think of for D4 to be behaving in this way.If the series resistance is open for whatever reason there is still a capacitively coupled path which you can see in some of the hand drawn schematics in the thread linked above.It seems the most logical D4 is open unless there's an open signal path inside the scope after the PCiE socket and before the comparators.Anyways, if you need any SPL2016 measurements ping me.

author: jnz
author_rank: Frequent Contributor
timestamp: March 15, 2022, 05:42:14 pm
content: D4, octopus to pin header, 91.6ohmsD4, G1 header to PICe, nothingD4, G2 header to PICe, 92 ohmsSo, yes. That is the problem, but crazy that my Fluke 28 II shows no resistance, diode, connectivity at all, but the scope was showing a fairly large pulse compared to what I would think a small pulse from overshoot on a non-connected line would look like.I'll have to contact Siglent USA and see what the warranty on this looks like.

author: tautech
author_rank: Super Contributor
timestamp: March 15, 2022, 08:41:38 pm
content: Quote from: jnz on March 15, 2022, 05:42:14 pmWarranty is 1 year on all probes and if this SPL2016 has had minimal use you may never have seen the D4 line as faulty. In my view you have a good case for a replacement.info@siglentna.com

author: jnz
author_rank: Frequent Contributor
timestamp: March 28, 2022, 06:01:16 pm
content: Siglent has been really quite awful trying to replace this.Still working on it.

author: bdunham7
author_rank: Super Contributor
timestamp: March 28, 2022, 06:13:10 pm
content: Can you just connect one of the other digital lines to your CS test point? They should then show the same signal. If not, your RMA case should be clear.