MSOX2024A scope probe problem - Page 1
Forum section: electronics / testgear

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 26, 2013, 02:54:26 am
content: I have just received my MSOX2024A.Unfortunately my scope probe retractable hooks keep falling off the probes. What is the deal here? Surely this can't be the way they are designed.My old HP probe hooks seem to hold on by friction via the soft rubber and close tolerance of the probe and the hook. I can hook the probes onto something and they hold their own weight. My new probes just fall out??The new probes look like they are just hard ABS plastic on the probe and the hook. I have wrapped a couple of turns of sticky tape around the probe to help hold them in and while it does improve things it is surely not necessary.Hopefully I am just not seeing the obvious, please explain why.ThanksN2863Bhttp://www.home.agilent.com/en/pd-1938449-pn-N2863B/passive-probe-101-300-mhz-12-m?nid=-34025.964559&cc=US&lc=eng

author: DavidDLC
author_rank: Frequent Contributor
timestamp: April 26, 2013, 02:59:33 am
content: I have those probes and I don't see the issue you are seeing. And yes they use friction to hold them on place.David.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: April 26, 2013, 03:01:02 am
content: Correction I have the N2862B which are pretty much the same plastic design, but with different bandwith.David.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 26, 2013, 03:03:39 am
content: If I hook them onto something the hook stays on but the probe falls out.I have pushed them in as far as they go, but they don't stay in.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 26, 2013, 01:24:21 pm
content: Ok the problem is sorted out.Just shove them on even harder, and they stay on. Much harder than the HP ones I am used to.I think I did state somewhere it was probably me and not the scope leads.One of them is actually a bit wrong, obviously the first one I looked at. It clicks like a momentary switch when you put the hook on, so I thought it had reached it full travel.The others don't click.Anyway Agilent called me up at dinner time to respond to my email and helped me out and are sending some replacements.All good except for my pride.

author: AndyC_772
author_rank: Super Contributor
timestamp: April 26, 2013, 01:55:34 pm
content: I have N2890A probes and there's no positive 'click', the tips just seem to stay in place by friction. I think there's a slight taper to the body of the probe which fits a corresponding taper in the spring tip.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 26, 2013, 02:10:34 pm
content: The click is only in one of them, out of four, it was the first one I looked at, and I guess because it clicked I didn't push with the required force. I don't know what is making the click. Anyway it's all solved now.

author: jmole
author_rank: Regular Contributor
timestamp: April 27, 2013, 07:42:38 pm
content: I had the same problem with mine; just have to shove them on as hard as possible like you said. Felt a little anxious doing it the first time, but it works.

author: Baliszoft
author_rank: Frequent Contributor
timestamp: April 27, 2013, 08:20:32 pm
content: These agilent hooks piss me off every time i am using them. It is hard to put them on the probe (you have to aim exactly into the middle) also the hook can twist/rotate when pressed out and cant lock back in again. After getting used to the tek probes/hooks, these are an absolute fail!

author: jmole
author_rank: Regular Contributor
timestamp: April 28, 2013, 12:30:56 am
content: Honestly, I cant figure out why the "mini-grabber" form factor isn't the standard for oscilloscope probe tips. Cheap as hell, and much more flexible in terms of what you can probe. For that matter, why are probes so damn BIG? Seems like a passive probe has no need to be larger than the coax that connects it.

author: Unknown
author_rank: Unknown
timestamp: April 28, 2013, 12:50:06 am
content: The mini-grabber is fairly useless for SMT. Good luck hooking it up to SOIC, let alone SSOP/TQFP. Or a 0805 passive. A sharp probe tip can do a decent job on all of those.The probe head needs to be comfortable to hold. It needs to contain some passives (eg. attenuator, you want this as close to the probe tip as possible). The ground lead needs to connect to it. The connection to the coax cable needs to be sturdy, so you need decent strain relief. The probe itself also needs to be quite sturdy. All of these add to the size.Some probes have a more compact design. This is apparently more expensive, since the cheaper probes all use a similar form factor that Tektronix used in the late seventies. Note that Agilent lists 'low-cost' as one of the advantages of the N2863B. The more expensive N2872A has a smaller form factor. Tektronix had some even smaller probes in the past (eg. the 2.5mm P6133 that Mike from Mike's electric stuff likes), but these were replaced by sturdier 3.5/3.8 mm probes.

author: jmole
author_rank: Regular Contributor
timestamp: April 28, 2013, 01:14:34 am
content: Quote from: alm on April 28, 2013, 12:50:06 amMini grabbers will definitely work on SOIC, SOT-23, or any 1.27mm pitch component, I've done so many times.I'm not suggesting that the mini-grabber is the *only* probe tip, simply that probe tips should accept a mini-grabber by default.

author: Unknown
author_rank: Unknown
timestamp: April 28, 2013, 08:13:07 pm
content: Quote from: jmole on April 28, 2013, 01:14:34 amThisis what Pomona refers to as mini-grabber. That's quite similar to the witch's hat that ships with most scope probes. It's also what turns up if I do a Google Image search for mini-grabber. These barely work on SOIC, and only on the corner pins. Do you have something else in mind?

author: jmole
author_rank: Regular Contributor
timestamp: April 28, 2013, 08:54:42 pm
content: Ah, misunderstanding then.These are what I'm referring to, same kind that come with logic analyzers:http://www.circuitspecialists.com/xkm-black.html

author: ben_r_
author_rank: Frequent Contributor
timestamp: April 28, 2013, 10:21:47 pm
content: Yep, I had the same issue when I first played with the MSOX20024A's probes. Then I just jammed em in there and they stay fine now.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 02, 2013, 06:45:34 pm
content: heyjust wanted to tell youthere is mini grabber ( hook )and there''s micro grabber ( the one like tweezers )so next time you'll know to differentiate

author: jmole
author_rank: Regular Contributor
timestamp: May 02, 2013, 07:10:40 pm
content: semantics aside, "micrograbbers" are way more versatile than traditional scope probes, and the reduction in size seems like a total win to me.

author: Unknown
author_rank: Unknown
timestamp: May 04, 2013, 03:24:23 pm
content: Quote from: eevblogfan on May 02, 2013, 06:45:34 pmPomona uses bothminigrabber(R)and micrograbber(R) to indicate different sizes ofgrabberandpincertype clips.Somedistributorsrefer to the Agilent 10075A clips for 0.5 mm TQFP/SOIC devices as 'micrograbbers'. The term mini grabbers is occasionally used for cheap Chinese knock-offs of EZ-hook XKM mini-pincers. I would propose that both terms are meaningless for anything but indicating some fairly small test clip.The EZ-hook/Tek KlipChip clips are great for not too high density SMT devices, and through hole no larger than DIP or 1/4 W resistors. Not sure if I agree that they're more versatile though. They are less stable than grabber hooks (on parts that fit both), I've had them detach much more often. The grabber hook is fairly useless on a modern circuit board, but is much better for grabbing larger diameter leads (eg. power resistors) or wires. So the manufacturer still would have to offer both.The Agilent 0.5 mm grabbers that Dave showed in his latest Mailbag segment are even less versatile. They're fairly fragile, and only suited for the fine pitch devices they were designed for. I wouldn't use one for DIP or even SOIC, they're way too expensive for that.Most good probes either ship with or offer as an optional accessory flying leads adapters with 0.020/0.025" sockets on the end that accept various SMT grabbers. These adapters also have the advantage of lowering the mass pulling on the connectors (see my earlier comment about detaching clips). I really liked the Tek P656x form factor, but I guess they were too fragile.There also appears to be a mechanical problem with designing slip-on pincer-type clips. The only example I know of for normal passive probes is a Tektronix IC grabber slip-on clip that was probably designed in the eighties or early nineties for grabbing DIP leads. It was absolutely worthless, wouldn't hold on to anything with the weight of the probe.