Grounding pins for Keysight MSO logic probes - Page 1
Forum section: electronics / testgear

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 05, 2018, 08:58:36 am
content: Has anyone found a good solution for additional grounding pins for Keysight MSO logic probes, to allow them to plug into an 0.1" pin pair with good grounding.The black pins pictured on the right come with the probes but they only supply 4 of them. I can't immediately find a part number to order more.Best solution I have at the moment is crimping a 0.1" header pin into a harting ( I think) 0.1" socket contect, but bending the pin is dicy as they tend to snap.

author: JFJ
author_rank: Regular Contributor
timestamp: September 05, 2018, 12:45:29 pm
content: Quote from: mikeselectricstuff on September 05, 2018, 08:58:36 amThe logic inputs of every Agilent/Keysight MSO that I've encountered, are single ended (with all the logic probe ground pins commoned within the pod). So, would there be any significant benefit from using more than four grounding pins?

author: MarkL
author_rank: Unknown
timestamp: September 05, 2018, 02:31:35 pm
content: The E5382B flying-lead probe set for logic analyzers appears to use the same ground extender. It's part #16517-82105 for a kit of 20:https://www.keysight.com/upload/cmc_upload/All/E5382-97003.pdfThe Keysight parts page shows they are orderable, and at the usual Keysight insane pricing of $390 for the kit of 20.Just curious... what MSO is this for?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 05, 2018, 03:42:06 pm
content: Quote from: JFJ on September 05, 2018, 12:45:29 pmOn the MSOX, the grounds don't meet until the front-panel connector, so you have approx 1m of "floating" ground inductance on an ungrounded probe.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 05, 2018, 03:46:18 pm
content: Quote from: MarkL on September 05, 2018, 02:31:35 pmQuoteMSOX3104T

author: GlowingGhoul
author_rank: Regular Contributor
timestamp: September 05, 2018, 04:34:01 pm
content: $30 delivered, brand new:https://www.ebay.com/itm/20-PCs-Lot-Hewlett-Packard-Agilent-16517-82105-Ground-Extenders-NEW/332761137873

author: MarkL
author_rank: Unknown
timestamp: September 05, 2018, 04:36:30 pm
content: Quote from: mikeselectricstuff on September 05, 2018, 03:42:06 pmOn a MSO-X3104A, the logic grounds are commoned in the little box that the flying leads plug into, before the long ribbon going to the scope. I was able to confirm this with some 4-wire ohms measurements. So, much less than 1m.The 3104T probes are obviously a different and updated design. The old design is still shown in the manual, but it would surprise me if they left the ground that long per signal in the new design.Some of the literature shows the new probes in 4 groups of 4. Maybe you're meant to use one of those ground extenders on one ground in each group, and then the ground is commoned within each group. That's why they supplied 4 extenders. Just a guess looking at the pictures.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 05, 2018, 04:47:51 pm
content: I'd also expected the grounds to be commonned in the blocks of 4 probes, but was surprised to find they aren't linked until the connector at the end.The only function of the blocks is labelling and to stop the ribbon cores peeling apartMeasures 0.8R between grounds, inductance 1.5uH at 10KHz.

author: MarkL
author_rank: Unknown
timestamp: September 05, 2018, 05:07:21 pm
content: Wow, that's pretty lame.I wonder what the signal integrity looks like at the big connector going into the scope?