probe compat (tek 2400 series) - Page 1
Forum section: electronics / testgear

author: linux-works
author_rank: Super Contributor
timestamp: February 26, 2014, 06:36:02 pm
content: I'm looking for probes for the 2465b and the compatibility charts all list the p6137 as the highest tek probe that is 'supported'. I also see 6138 and 6139 but they are 'supposed' to be used with another series of scope. I'm still waiting for delivery of my 2465b and am trying to gather up some probes before it gets here. should I just stick to the p6137 since its the last 400mhz probe tek officially lists for the 2400 series or can I safely jump up a model # or two. on the bay, there is more choice in some models than others, so I'd rather not be stuck at the 6137 if I don't have to.I know about the comp range of cap that has to match with the probe and scope. but I think, if I'm reading it right, that the 6138 and 39 is also in the same range as the 2400.could there be ID pin differences or something to that nature?(still new to this series of scope, so that's why I'm asking such a basic question)

author: MarkL
author_rank: Unknown
timestamp: February 26, 2014, 10:51:50 pm
content: The ID pin is compatible among Tek passive probes. The scope uses it to adjust the attenuation factor for display purposes (V/div, cursor values, etc.). In my testing I've found that manufacturers do make slight tweaks to the response curves to match specific scopes, but it's never been much to worry about, so buying a probe >= to your scope BW is fine. Stick with the P6137 if you can get it, but I wouldn't lose sleep over it.Besides the compensation range match, be aware of the tip size and any accessories you might want. The grounding methods also vary on the Tek probes. It could have a slide-on doughnut, a sleeve where you plug the ground in the back, or a regular clip.Used probes rarely come with their original tip and ground accessory packages and these can be hard to track down. Try to get what you need with the purchase.

author: linux-works
author_rank: Super Contributor
timestamp: February 27, 2014, 12:09:41 am
content: thanks.I actually got the scope in early and am trying it out now. I have one 6137 probe and it seems fine, and its button ends up sending an ID signal to the scope, it displays 'id' at the bottom and seems to move the trace. I haven't checked if it just simulates a ground or moves the trace in a way for you to 'notice' it.I read on one description that the id button triggers the 'auto' feature but that does not make sense and does not seem to be true.I have other tek probes (6106, I think; 250mhz version) and that button does NOT trigger an ID display, yet it does simulate a grounding. I'm curious how these 2 probes deal with the probe-body button. they both have a single extra wire at the bnc side but maybe they assign different meanings to it. I'm still learning this new scope.oh, and the accessories, like you say, often don't come with the probe. I'm trying to find ones that are mostly complete. at least the 'witch hat' is only a $10 item and still buyable at mouser, if you can believe it. I don't find the grounding sleeve or ring as spare parts easily, but a shop in greece (which seems to be very much into the 24xx series, for parts) has the sleeve, the stupid wiggly ground wire (lol) and other things that often are not included. its a long lead time for them to ship and for me to get it, but I'm not finding a lot of places that stock these old accessories.

author: MarkL
author_rank: Unknown
timestamp: February 27, 2014, 03:24:30 am
content: Quote from: linux-works on February 27, 2014, 12:09:41 amI'm certain it's changing the readout pin resistance (to ground) from 11k to something else, possibly 510 ohms. Check it with an ohmmeter.The 6106 does have a ground reference button. I don't think the button does anything to the readout pin.

author: BravoV
author_rank: Super Contributor
timestamp: February 27, 2014, 03:31:46 am
content: Just fyi, specifically for P6137 used in 2465B, the button at the probe handle is for activating the "AUTO" feature.

author: linux-works
author_rank: Super Contributor
timestamp: February 27, 2014, 03:52:46 am
content: it does not do that for mine. could there be a setting that controls this? on mine, the button on the p6137 probe just moves the whole signal for that channel up a bit. and it says ID at the bottom left. nothing does AUTO on my 2465b other than the actual auto button on the main chassis.

author: MarkL
author_rank: Unknown
timestamp: February 27, 2014, 04:02:22 am
content: The service manual says it just does an ID by moving the associated trace up 0.5 division so it can be located on the screen.

author: linux-works
author_rank: Super Contributor
timestamp: February 27, 2014, 04:19:03 am
content: that's exactly the behavior I see. it moves up by 'that' much (I didn't notice exactly, but half a division seems about right).

author: linux-works
author_rank: Super Contributor
timestamp: February 27, 2014, 04:20:20 am
content: btw, you would not want to have setup everything the way you want it and then, by accident, hit the 'auto' button! on the probe, its too easy to hit. so I would conclude that tek knew this and would not have mapped the probe button to 'auto'.

author: BravoV
author_rank: Super Contributor
timestamp: February 28, 2014, 07:49:38 am
content: Feel such a noob, just realized all this time that the probe button has been assigned to AUTO by the previous owner.Apparently I missed this particular part in the manual, and just knew it that it can be assigned to other functions.

author: linux-works
author_rank: Super Contributor
timestamp: February 28, 2014, 08:18:29 am
content: oh, so it IS assignable? ok, well, at least they didn't hard-bind it to auto.I have not read the manual yet. but I did take the scope apart