Suggestions on buying scope probes? - Page 1
Forum section: electronics / testgear

author: nsd_c
author_rank: Contributor
timestamp: October 03, 2015, 05:49:05 pm
content: Hi everyone,So I've recently acquired an Agilent 54621D 60 MHz MSO off of eBay and would like to obtain probes to use with it. I'm looking at probes from Agilent and have noticed some strangeness. For example, the N2862A/B (the 'B' suffix probes replaced the 'A' suffix, though they seem identical (?)) is a 150 MHz 10:1 probe with 1.2m coax length, which includes replaceable tips and a probe tip to BNC adapter for $111 (USD) new. Then there's the 10074A/B/C/D 150 MHz 10:1 probe with 1.5m coax length, which has been around longer (evidently) and seems like (though I can't quite tell) that it might be a little bit of a bulkier probe. This is advertised by Agilent (er, Keysight) as a " rugged" probe, whatever that means. For some odd reason, it is $193, yet (as far as I can tell)does nothave replaceable tips. It also doesn't come with a BNC adapter, and that is (for some reason) $70 (!!!!).Does anyone reallyneeda "rugged" probe? Frankly I don't see what the point is, butsomethinghas to explain that the price is nearly double. Why would anyone pay twice as much for a probe if you can't replace the tip? What's the point of it being "more rugged" then? Afaik both are also made in Malaysia, so the country of origin doesn't factor into the cost.Adding to the strangeness, it seems as though the 10074's routinely sell forlessused than the N2862's. Does anyone have any idea why and could perhaps make a recommendation for one over the other? I've also noticed that the 10074 is the "correct" probe for the 54621D, but does that even matter? The scope has only a 60 MHz bandwidth.Also, some users are saying that used probes should absolutely be avoided, and only to buy new. How true is this? Does apply less to lower bandwidth probes?Lastly, I've noticed that 300 MHz passive probes seem to a bit more than their 150 MHz counterparts, but that seems kinda silly to me when the forum wisdom is saying that beyond or even approaching 100 MHz, passive probes are out. Why the heck would anyone buy a 500 MHz passive probe then?I will say I've used N2862A's before and I did like them.TL;DR,Is it worth buying a passive probe that's higher than 150 MHz? (I realize my scope is only 60 MHz, but I'm thinking about if I ever upgrade, which is likely.)Is the BNC adapter that comes with the N2862A worth having? I saw a video that Dave posted about this, but why can't I just use matched length coax with terminators/T fittings?Is there anything credible to Agilent/Keysight's claim that the 10074 is "more rugged"? Is there any point to that?Is there any advantage/disadvantage to having a longer probe length (aside from the obvious being-able-to-reach-things-further-away)?How important are replaceable tips, and for anyone who's owned a 10074/10070/10073, are the tips actually replaceable or no?I'd really appreciate any info on any of these!

author: tautech
author_rank: Super Contributor
timestamp: October 03, 2015, 07:04:07 pm
content: Seems like you're stressing to get Agilent probes for your Agilent scope and I ask why bother when for the BW you need any cheap 100 MHz probe will be more than sufficient.P6100 probes are cheap and perfectly functional and can be bought for less than US$20 a pair.Heaps of them on eBay and Aliexpress.If they're not rugged enough for you I'd be suprised.

author: nctnico
author_rank: Super Contributor
timestamp: October 03, 2015, 07:50:10 pm
content: And even then: get new ones when they are worn out. Oscilloscope probes are like shoes: you shouldn't want to buy them second hand and they do wear out.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: October 03, 2015, 09:39:57 pm
content: Both probemaster and avent make great us probes! I own 100mhz fixed 10:1 probes there about 30 a pop but you can find new pairs on ebay for 20ish a set. Probemaster acually makes x1 probes with 20mhz rating. Both brands sell fixed and switchable styles. If you have the cash i recomend buying fixesd x1 and x10 probes from either company.

author: forrestc
author_rank: Unknown
timestamp: October 03, 2015, 10:14:57 pm
content: I just bought a brand new MDO3024, and promptly took the expensive (and admittedly slightly higher quality) probes and put them away so I couldn't destroy them. They'll only be used for those extremely critical measurements.I then replaced them with a set of probemaster probes. I ended up with a set of 4900 series probes (10X, 250Mhz, w/deluxe kit), and a couple 6165 probes (250mhz, 10X, with flying leads w/ pin headers).What I really like with the 4900 set is the range of accessories available for not a lot of money. (Seehttp://probemaster.com/oscilloscope-probes/4900-series/accessories/). Many of these are included in the deluxe set. I've found the 4954WT and the 4965 WG to be particularly helpful where I'm either dealing with small components and a micro grabber and/or 0.1" headers.Although I do feel the official Tek probes are more suitable for critical measurements, I sure couldn't see any meaningful difference in A/B tests between the probemaster probes and the Tek probe, even quite a ways up in the frequency range. The only difference I could see could be 100% attributed to the extremely low 3.9pf loading on the tek probes.If it was me, I'd just buy either a basic or deluxe 4900 series set from probemaster. For the 60Mhz scope you have, you should be ok with the 150mHz edition which is only $81US for the deluxe kit, or $52 for the basic. Or if you care about pricing and don't need the flexibility of accessories, you could also get away with the 3900 series probes for even less.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: October 03, 2015, 10:21:01 pm
content: Quote from: tautech on October 03, 2015, 07:04:07 pmSeconded.Unless of course you are going to be using them to tie up your victims to a chair or something....

author: G0HZU
author_rank: Super Contributor
timestamp: October 03, 2015, 11:37:49 pm
content: QuoteI guess it depends on the condition of the used probes. I would much rather buy a decent example of a used Tek or HP probe compared to a new cheapo probe with a dodgy brand name.All of my scope probes were bought secondhand and they all still work fine after many years' use here. Most are Tek made and one is HP and two are RS. The croc clip wire on the RS probes tends to fray and break every so often but it's easy enough to repair it. The RS probes date back to the 1990s but still work fine apart from the croc wire issue.

author: Howardlong
author_rank: Super Contributor
timestamp: October 04, 2015, 12:02:20 am
content: For a 60Mhz scope, if that is all you're going to be using for the near future, there is little point in investing in expensive probes.However, if you really want Agilent, there are some 10073C 500MHz probes on ebay at $55 each herehttp://www.ebay.com/itm/Agilent-10073C-Passive-Probe-10-1-500MHz-1-5m-10073C-hp-10073C-HP-10073C-/201270061358I have about eight of those 10073C probes that I've used on both the 54622D and 54642D, as well as other more modern scopes. Just make sure that the compensation capacitance of any probe you purchase is within the range of the scope's nominal input capacitance.The 54621D is a really nice scope by the way, possibly a bit lacking in bandwidth these days and also running equivalent time at the upper ends of the timebase, but it's super responsive, a great UI and simple to use. Boots super quick too.

author: JoeB83
author_rank: Regular Contributor
timestamp: October 04, 2015, 12:08:14 am
content: I'd agree with the others who've recommended buying some cheaper $20-$30 probes, but I do want to say I have a number of N2862A and 10074C probes myself, and I like them a lot.

author: GreyWoolfe
author_rank: Unknown
timestamp: October 04, 2015, 01:12:49 am
content: Quote from: alsetalokin4017 on October 03, 2015, 10:21:01 pmHeaven forbid! I would never use my probes for that. I have 8 AWG wire for that.

author: G0HZU
author_rank: Super Contributor
timestamp: October 04, 2015, 01:50:32 am
content: I don't think I've ever paid more than £10 for a used scope probe. Most of mine were £2 to £5 each bought at radio rallies including my HP 10073A probe.I really don't think it's worth paying more than that for a basic x10 scope probe for home use. I prefer the HP or Tek probes for the build quality and overall reliability so I'd much rather pay a fiver for a decent old Tek or HP probe than pay the same (or more) for a cheapo new probe on ebay

author: nctnico
author_rank: Super Contributor
timestamp: October 04, 2015, 12:42:18 pm
content: I OTOH have seen lots of problems with older probes (broken wires, dodgy ground connections) etc. People don't sell their best probes!

author: AndyC_772
author_rank: Super Contributor
timestamp: October 04, 2015, 12:56:46 pm
content: It can be a bit of a lottery. I bought a used set of Tektronix' excellent P6139A probes from China via Ebay, and they worked perfectly. On the other hand, I also had an identical probe which I'd had from new go intermittent and then die, thanks to a well-documented problem with tin whisker growth.The Agilent probes I now use are bulkier and more awkward to use, but they do come with replaceable tips. In a very rare instance of generosity, Agilent even include a couple of spares in the accessory kit bag with the probe, so you never have to put up with a blunt tip.

author: Rupunzell
author_rank: Frequent Contributor
timestamp: October 04, 2015, 03:51:01 pm
content: Truly DIS_LIKE cheap O'sope probes or any variety as they are more often than not the source of measurement error, wasted time and much grief. Cheap O'scope probes are very much a false economy. The realization of this occurs the first one comes to the realization that the amount of time wasted due to O'scope problems was simply not worth the initial cost savings.That said, time invested in finding good used Tektronix (in this case proper Agilent) probes on ebay or else where is worth while. There are really good ones for around $20 USD. Another way to play this game is to purchase a probe lot from ebay, then sort out the best from the lot and put the remainder back on ebay to offset the initial cost of the probe lot.Also important choose the correct and most ideal probe for the required measurement. This seemingly simply detail is the difference between gaining a very good and accurate measurement vs a measurement full of errors. There are also safety issues to consider like HV probes and their de-rating requirements and more.Bernice

author: Muxr
author_rank: Super Contributor
timestamp: October 04, 2015, 04:04:24 pm
content: P6100 all the way. At 60Mhz there will be no difference that you can tell between them and more expensive options. P6100 are built well and are cheap. Heck I even use them on my 500Mhz scope most of the time. I only whip out the "premium" probes when I think I need them.

author: tggzzz
author_rank: Super Contributor
timestamp: October 04, 2015, 05:32:19 pm
content: Quote from: Rupunzell on October 04, 2015, 03:51:01 pmOh yes!QuoteMost definitely. Since this topic comes up frequently, I've listed the refs I've found most useful athttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/

author: joeqsmith
author_rank: Super Contributor
timestamp: October 04, 2015, 05:34:09 pm
content: I bought a few Hantek PP150 probes and am happy with them. I made the following video where I compare them with a few other probes.

author: nbritton
author_rank: Frequent Contributor
timestamp: October 08, 2015, 06:52:11 am
content: Quote from: joeqsmith on October 04, 2015, 05:34:09 pmWhat was the roll-off like on the Hantek PP150? If I spent an extra $10 for the PP200 do you think that would yield even better performance?

author: tggzzz
author_rank: Super Contributor
timestamp: October 08, 2015, 07:25:46 am
content: Quote from: nbritton on October 08, 2015, 06:52:11 amSince we have no idea of your scope nor what you intend to use it for, how could anybody possibly answer that sensibly?For a table showing theoretical scope+probe performance, seehttp://bristol.hackspace.org.uk/wiki/doku.php?id=oscilloscopeprobesTo see how that table is derived, and many other topics about probes, seehttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/

author: SteveLy
author_rank: Regular Contributor
timestamp: October 08, 2015, 07:31:48 am
content: The price vs quality curve is a steeply rising exponential, so the cost of trying out cheaper probes before upgrading is practically insignificant; so get a pair of P6100s to begin with. If they don't fulfill your every need then you can spend an order of magnitude more on your next set. The possibility that you may upgrade to a better scope in the future is irrelevant for the same reasons. Also your older slower scope will be able to keep its own perfectly adequate probes.

author: BravoV
author_rank: Super Contributor
timestamp: October 08, 2015, 07:53:17 am
content: About these Hantek cheap probe, just fyi, the retractable hook tip can be a perfect replacement for genuine Tektronix high speed classic passive probe, for example P-6137 400Mhz capable. Especially the genuine Tek's hook replacement is quite pricey, like at ebay some are selling just the hook only for > 10 bucks.

author: nsd_c
author_rank: Contributor
timestamp: October 09, 2015, 02:50:25 am
content: Wow! I did not expect so many responses! Thanks everyone for the suggestions. I ended up buying two brand new Agilent 10074D 150 MHz 10:1 passive probesoff eBayfor $37 USD each. Two day shipping for $4, too. (not bad!)For anyone else wondering about these: They're not the most compact probes around; the Tektronix TPP series are really teensy, but they're perfectly fine. They have a bent wire tip, not a piece of cut sheet metal like on a lot of Tek probes. (I personally like the sheet metal tips better.) With the hook tip removed, there's no gold plating on the tip, and no, it doesn't seem replaceable.The probes themselves are made in Japan (I wonder who actually made them?). There's only one compensation adjustment, which is where the probe attaches to the scope, not on the probe. There's also a ground ref. switch on the probe handle; not sure why you'd really want that but it's there. There's no BNC adapter included either, like with the N2862/'63. Overall I'm pretty pleased with them though; they're decent probes. Nice overall feel to them.Quote from: Howardlong on October 04, 2015, 12:02:20 amFor the money, that's probably a very good option. I did see those but (and this is likely stupid) $110+shipping was a little more than I wanted to spend--but again, I'm probably stupid for not paying $30 more for over three times the bandwidth.Quote from: Howardlong on October 04, 2015, 12:02:20 amYeah it is really nice! I had a Tek 2430A in which the hybrids died and some other crusty 2 MHz Tek scope (can't remember the model atm) that kinda did the business, but was massive and the bandwidth just wasn't high enough. Naturally I couldn't really do digital stuff with it either.Quote from: tautech on October 03, 2015, 07:04:07 pmAbsolutely true, I was kinda stressing to get Agilent probes. Partly because my University has plenty of them and I was familiar with some models of them. I've used some Tek probes as well, but I don't remember model numbers for anything I liked off-hand.Regarding the cheapie $10 eBay probes, I've been wary of those, but I will say that I ended up seeing a pair in person shortly after I bought those 10074Ds and I have to say, they do seem really decent! I'd still rather buy a name brand made in Japan though with some (probably) more reliable QC.Quote from: tautech on October 03, 2015, 07:04:07 pmRight, that's kinda what I was trying to say: I can't really imagine one plastic-handled probe being "more rugged" than another. It's not like I'm using these in a warzone, just at a workbenchQuote from: BravoV on October 08, 2015, 07:53:17 amI've actually seen eBay sellers that are selling clones of those Tek probe tips. (Incidentally, I just today found a bag full of 11 of brand new Tek probe tips of an older style (I think they fit the P6130 and friends) at a local surplus place that I snatched up.)Quote from: rwgast_lowlevellogicdesin on October 03, 2015, 09:39:57 pmI took a look atAvex(I think that's what you meant) andProbe Master, and man, I wish I didn't get impatient and buy those 10074Ds because probes from both of those companies seem really awesome for the money. The parts are so cheap! Plus I do like that they're manufactured domestically.

author: djacobow
author_rank: Super Contributor
timestamp: October 09, 2015, 03:57:38 am
content: I have a pair of Probe Master 4906-1K's. I use them on a DS2072 mod'd to 200MHz and have zero problems with them and they deliver the promised bw with no issues that I can see.I like that they are fixed at 10x and that they are USA made. I got the deluxe kits. I rarely use most of the accessories, but they're nice to have.With 1m cables, they were the shortest probes I had ever used. At first I was disappointed, but, to my surprise, I have come to really appreciate how short they are. It's just less spaghetti ratsnest on the bench.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 09, 2015, 04:29:53 am
content: Quote from: nsdecicco on October 03, 2015, 05:49:05 pmThere is a sensible reason for the "more rugged" probes.If an EE is going to use probes with his own "tame" Oscilloscope,in a proper Lab,or even a hobbyist in a home Lab,reasonably fragile probes will give long ,reliable lives (providing they are decent quality to start with)Probes ,& Test Equipment in general,in a workshop environment,where they will be used by multiple staff, generally "pushed from pillar to post",chucked into roadcases,& taken to remote sites,with the possibility of being damaged during hurried packing & unpacking,need to be as rugged as possible.Tektronix & HP probes are generally much tougher than the "El Cheapos",but most workshops end up with a drawer somewhere full of probes with bits missing or broken.These usually get chucked out eventually,only to be rescued by Techs who make up "Frankenprobes" out of the bits for their home Labs.RE "El Cheapos"-----"Replacing them like blown fuses" is OK if like me,you are 5 minutes away from an Electronics shop,but when the nearest one is 1500km away,you need to know you have a probe with a high probability of working.

author: tggzzz
author_rank: Super Contributor
timestamp: October 09, 2015, 07:25:05 am
content: Quote from: nsdecicco on October 09, 2015, 02:50:25 amGood choice; I have a pair of 10074Cs and so does the local Hackspace.The only limitations I've found are those inherent in all 10* "high impedance" probe:theyaren'thigh impedance; they are 100ohms(!) reactive at 100MHzif you use the 6"/150mm ground lead, a digital signal will ring at ~100MHzThe second point can be cured with a simple homebrew attachment, seehttps://entertaininghacks.wordpress.com/2015/04/23/scope-probe-accessory-improves-signal-fidelity/The first point can be cured by either an expensive fragile active probe, or a cheap robust "low impedance Z0" probe with >1GHz bandwidth and 500ohms or 1000ohms impedance. They can also be quickly homebrewed, which can be an advantage if you discover you need several. See the "homebrey/diy" section inhttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/

author: Howardlong
author_rank: Super Contributor
timestamp: October 09, 2015, 12:12:18 pm
content: Quote from: tggzzz on October 09, 2015, 07:25:05 amIndeed, although the "new" Tek probes such as the 250MHz TPP0250 are 3.9pF, (400 ohms @100MHz) and it shows. Problem with these probes is that they only work with certain compatible Tek scopes as the compensation is performed inside the scope, not on the probe.

author: dan3460
author_rank: Frequent Contributor
timestamp: October 09, 2015, 02:02:41 pm
content: Any suggestions for buying a probe (or modifying one) to work on a Tek 2460, the originals 10X have a little pin that tells the scope this. I bought this scope (non functioning) for $20, it hurts to pay $60 - $80 for a used probe.

author: tautech
author_rank: Super Contributor
timestamp: October 09, 2015, 06:56:47 pm
content: Quote from: dan3460 on October 09, 2015, 02:02:41 pmThere are threads here that describe how to mod probes AND the resistor values needed for your scope to recognize the correct attenuation needed.But to find them.Hopefully other members will come to your rescue.

author: mtdoc
author_rank: Super Contributor
timestamp: October 09, 2015, 07:16:24 pm
content: As others have said, the cheap TP6100 probes available on eBay are very good for the price and more than adequate for your scope.SeeTHIS THREADfor details.

author: tautech
author_rank: Super Contributor
timestamp: October 09, 2015, 11:21:14 pm
content: Quote from: dan3460 on October 09, 2015, 02:02:41 pmCouple of threads on this:https://www.eevblog.com/forum/testgear/'spoofing'-a-tektronix-x10-readout-pin/https://www.eevblog.com/forum/testgear/automatic-probe-attenuation-setting-just-a-resistor-(tektronix-tds320)/

author: Howardlong
author_rank: Super Contributor
timestamp: October 12, 2015, 11:44:55 am
content: Quote from: dan3460 on October 09, 2015, 02:02:41 pmI just picked up a pair of Agilent 1165A 600MHz passive probes for $76 total. These have the standard 11k Hi-Z 10X readout pin compatible with both Tek and HP/Agilent/Keysight.http://www.ebay.co.uk/itm/Agilent-1165A-Passive-Probes-QTY-2-New-Unused-/151837366588If you're patient, you can pick up reasonable deals. Remember to check the compensation range of any probes you do buy is compatible with your scope though! In addition, there seems to be an increasing incidence of vendor lock in on probes and scopes these days, and although the scopes may have BNC connectors, they are sometimes recessed and so won't physically take some probes.