Should I buy a LeCroy 9354AM? - Page 1
Forum section: electronics / testgear

author: exit_failure
author_rank: Regular Contributor
timestamp: June 08, 2018, 12:56:58 pm
content: I haven't really used oscilloscopes much until now but I have some future projects where having one would be extremely helpful.I have the chance to buy a LeCroy 9354AM without probes in working condition for 50€. Is this reasonable and is the device suited as a general purpose scope for hobby use?If yes, are there some lowish-cost probes (is max. 40€ per probe a realistic price for something usable?) you could recommend for this scope?thanks a lotexit_failure/edit: added exact model number

author: tggzzz
author_rank: Super Contributor
timestamp: June 08, 2018, 01:07:53 pm
content: A quick glance at the spec for a 9354 (unknown varian) indicates that isn't a stupid price. Use fleabay to get a better idea ofsellingprices.Make sure it really is working; a beginner doesn't want to be debugging scopes.Whether it is suitable for your hobby depends on what you are building/testing in your hobby. You would be well advised to understand the different classes of scope probe and where they are used; concentrate on the safety aspects. Seehttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/for some starting material.

author: exit_failure
author_rank: Regular Contributor
timestamp: June 08, 2018, 01:20:55 pm
content: It's a 9354AM (500 MHz, 2GS/s). It was last calibrated in 2017 and didn't show any problems since then according to the seller.I unfortunately didn't find too many that were actually sold on ebay (only a single one on German ebay).Bandwidth and memory depth wise this scope should be usable for what I'm going to do.Thank you for the link. I'll have a closer look at the website./edit:The next project I'm planning is a simple 8 bit processor completely made out of TTL.

author: GerryBags
author_rank: Frequent Contributor
timestamp: June 08, 2018, 01:45:55 pm
content: I've seen a few sell on Ebay, 50 Euro is VERY cheap, especially for a 'scope a year out of cal. In fact I have seen two spares/repairs go for more than double that. You need PP02 probes (https://www.mouser.co.uk/ProductDetail/Teledyne-LeCroy/PP022-1?qs=sGAEpiMZZMvc81WFyF5EdtCRY0grCcnbiL%2fDPriCkbo%3d) That's a link for a new one (PP02-2) on Mouser. You can find the older probes second hand, but I've not seen one anywhere near 40 Euro, more like 100-120, I'm afraid. You see TEK P6139's come up for 50+ now and then, but I don't even think you'll find any new cheapo 500 MHz probes for that much.Weirdly, the probes seem to hold their value more than the 'scopes. Buying a cheap 4-channel, fast 'scope for bargain prices is much easier than finding 4 probes for that 'scope for the same money.

author: exit_failure
author_rank: Regular Contributor
timestamp: June 08, 2018, 01:58:10 pm
content: Since I'm planning on running the whole thing at 5 MHz tops, would 100 MHz or even 50MHz probes suffice?Is PP02 only the manufacturer's designation for 500MHz probes or is it something different?

author: Hydron
author_rank: Super Contributor
timestamp: June 08, 2018, 02:05:42 pm
content: Buy it (50 EUR is almost free!) and grab some cheap-but-OK probes to start with. I'm not sure what the current budget recommendation is here, but you probably don't need the fanciest probes to begin with, and even if you end up needing nicer passive probes in the future you'll still have some cheap spares.You're not going to get a useful 500MHz out of passive probes in many circumstances (sit down and work out what loading 10pF@500MHz is to your circuit, and that's not even thinking of ground lead inductance etc!). The 500MHz bit will be most useful with 50ohm sources (e.g. active probes), but the key is that you don't _have_ to use these until you need the bandwidth, whenever that is.Worst case if it's not doing what you need or is too big or something then you can pass it onto someone else without losing anything given the low low starting price.

author: GerryBags
author_rank: Frequent Contributor
timestamp: June 08, 2018, 02:32:35 pm
content: The PP02 probes come with LeCroy's probe interface which means you only have to compensate the probe once and the 'scope will recognize that probe and it's comp whichever channel you have it plugged in to. A probe without the interface will work fine but you would have to compensate the probe manually whenever it is moved between channels. A lower bandwidth probe, even if its BW is still above the speed of your signal, may not show you all aspects of the signal accurately, e.g.: the fastest rise-time a 'scope can show is down to a combination of the probe's specs and the 'scope's.Here's a LeCroy app note on probes which goes in to much more detail:http://teledynelecroy.com/doc/probes-probingHere's another article that cites a 'rule of thumb' on BW: The probe BW should be at least 5 times the BW of the signal you want to probe, to stop the capacative loading affecting the fidelity:https://www.testandmeasurementtips.com/understanding-oscilloscope-probes/I'd be inclined to view the 'scope as a bargain, saving you enough money to get at least two decent probes, and then get another two cheaper, slower probes for probing non-critical signals at the same time. This would let you use the BW of the scope if needed, give you two channels whose output you can trust fairly well, and still give you another two channels whose output needs to be taken with a pinch of salt.

author: nctnico
author_rank: Super Contributor
timestamp: June 08, 2018, 02:40:35 pm
content: 50 euro is a steal so just buy it. I wouldn't really bother about the probes. Just buy a couple of cheap 100 to 200MHz 1M Ohm probes which are switchable between 1:1 and 10:1. If you want to measure signals over 100MHz accurately you'll need entirely different probes anyway like low-Z or active FET probes (but these don't have to cost a furtune) or connect the signal directly. It seems unlike many other Lecroy oscilloscope the 9354AM does have peak detect so it is useful as a general purpose oscilloscope as well.

author: Ice-Tea
author_rank: Super Contributor
timestamp: June 08, 2018, 02:46:14 pm
content: 50€ is a steal. Buy it. Now.

author: james_s
author_rank: Super Contributor
timestamp: June 08, 2018, 04:29:28 pm
content: 50 Euro for a scope like that is a bargain even if it doesn't work, it will be worth more than that just for parts.

author: exit_failure
author_rank: Regular Contributor
timestamp: June 08, 2018, 07:55:41 pm
content: Thank you all very much, you have been extremely helpful. I think you told me everything I need to know right now. The links you gave me, are very helpful, too.