PCBite Handsfree Oscilloscope Probe! - Page 1
Forum section: electronics / general

author: LapTop006
author_rank: Unknown
timestamp: January 02, 2021, 08:40:42 am
content: Not seeing a thread for this one yet

author: LapTop006
author_rank: Unknown
timestamp: January 02, 2021, 08:42:21 am
content: For my actual comment, it's a shame they don't seem to have a sense pin on the BNCs so my scope would go into 10x mode automatically.Otherwise, I'm very tempted, for low speed signals I normally just solder a quick mod wire on, but this would absolutely be a better solution.

author: cgroen
author_rank: Unknown
timestamp: January 02, 2021, 10:26:28 am
content: I love these, I bought a couple of sets, both the 4 scope probes and a bunch of the SP10 probes (for my Saleae). Also the PCB holders are very nice and gets a very good gripHighly recommended!I got all mine from Batronix, not sure if they are the cheapest or not, they had it all on stock

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 03, 2021, 03:57:05 pm
content: Some time ago I saw a simpler version on Ali you can als DIY with a few sticks of wood, some tape and a small rack.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 03, 2021, 04:09:16 pm
content: Quote from: Doctorandus_P on January 03, 2021, 03:57:05 pmPogo pins they are very cheap and in the chinese design there is no weakly resistant naked iron that wants to fall and make a short circuit on the board.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 03, 2021, 04:32:13 pm
content: I found the video instructions for installing these probes!

author: cgroen
author_rank: Unknown
timestamp: January 03, 2021, 04:37:18 pm
content: Quote from: S. Petrukhin on January 03, 2021, 04:09:16 pmQuote from: S. Petrukhin on January 03, 2021, 04:32:13 pmS. Petrukhin,have you tried the PCBite products, or are you just talking to keep awake ?

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 03, 2021, 04:48:37 pm
content: Quote from: cgroen on January 03, 2021, 04:37:18 pmI train my breathing and steady heartbeat to avoid trembling in my hands.

author: tszaboo
author_rank: Super Contributor
timestamp: January 03, 2021, 05:43:02 pm
content: For this 200 EUR for 4 probe+ holder, this is entirely reasonable. For sure I've spent more time soldering tiny wires to the board again and again. I will try to sneak into this year's TE budget.

author: Per Hansson
author_rank: Unknown
timestamp: January 10, 2021, 06:09:50 pm
content: I have to give a thanks to Dave for the heads up on this item.After seeing his video last weekend I put in an order, as it is made in Sweden I had it just two days later.This gave me a good enough reason to start working on a servo I had been holding off on.It really does help to have a third hand when probing as we all know!After having an opto replaced and its SMD caps that where truly gone it now just needs some bulk caps.One of those was truly dead too, read just a few pF!And a new IGBT module as it was shorted, geez, not an inexpensive repair this one!

author: Hydron
author_rank: Super Contributor
timestamp: January 10, 2021, 08:01:19 pm
content: The one thing holding me back from grabbing one immediately is the question of whether it's compensation range can handle the ~9-10pF input of a R&S RTB2004 - the SP200 manual specifies 15pF minimum, but I find often that the range is larger in reality. Has anyone tried one with a low input capacitance scope?

author: Per Hansson
author_rank: Unknown
timestamp: January 10, 2021, 08:58:53 pm
content: The Fluke 225C Scopemeter in my picture has an input impedance of 1MΩ with 15pF according to its manual.The probe was already perfectly calibrated when I went into cal mode so maybe they use something like that at the factory for cal.I also have an analog Tektronix 2215 with 1MΩ & 30pF input impedance, as a sanity check I moved the probe to that and it was off.So I calibrated it to make a nice square wave and then moved the same probe back to the Fluke and then it was off there, being too high.Then I screwed the cal screw counter-clockwise till I got a square wave, and then I tried how much further I could go.It was about half a division, I realize that may not mean much but at least if the specs of the scope is right it means it handles less then 15pF.

author: Hydron
author_rank: Super Contributor
timestamp: January 10, 2021, 11:53:07 pm
content: Thanks for trying, good to know there is at least some range to play with.When you say half a div, do you know what proportion of the waveform that was? (i.e. if it was 4 divisions pk-pk, would be 1/8th). And do you know the proportion that it was under/overshot when you put it on the Tek having being adjusted for 15pF? Only asking in case you recall - please don't feel the need to spend more time on my behalf!I guess as a backup if I get one and it doesn't compensate then I can always throw some lumped C at it on the probe end - there is access to the PCB where the connector goes, a 0603 or 0402 cap should fit there and bump it up a bit (hopefully being at the probe end vs scope end isn't critical).

author: Per Hansson
author_rank: Unknown
timestamp: January 11, 2021, 04:30:23 pm
content: The calibration mode on the Fluke 225C Scopemeter is a walled garden: no settings can be changed so I do not know what it corresponds to, maybe it is written somewhere in the manual...I attached two photos, the first shows the calibration after it has been zeroed for the Tektronix 2215 with 30pF input capacitance.The second shows the lowest possible adjustment the probe allows.

author: bgm370
author_rank: Contributor
timestamp: January 11, 2021, 05:00:24 pm
content: Quote from: Hydron on January 10, 2021, 08:01:19 pmFWIW I did not have any problems compensating SP100 for RTB2004.

author: cgroen
author_rank: Unknown
timestamp: January 11, 2021, 05:09:40 pm
content: I compensated my 4 pcs SP200 on my Keysight MSOX3024T without any problems (14 pF/1M)

author: Hydron
author_rank: Super Contributor
timestamp: January 11, 2021, 05:11:51 pm
content: Quote from: bgm370 on January 11, 2021, 05:00:24 pmI think the compensation range spec is the same for the SP100 and SP200, so another promising datapoint, thanks!Per Hansson - pics also suggest that another ~5pF of compensation range is available, if 15pF = ~1div, thanks for taking the time to grab them.Will probably buy some then, looks like eevbloggers have grabbed the immediate UK stock though, so might be a wait (probably compounded by delays due to brexit)

author: Hydron
author_rank: Super Contributor
timestamp: January 28, 2021, 04:15:58 pm
content: ...and I can now confirm that the SP200 probes cal just fine with a RTB2004, and despite the lack of HF adjustment also have a reasonable rising edge with only a little overshoot (see pics - not perfect but should be good enough).Cheers for all who helped, and Dave for the video!

author: eTobey
author_rank: Super Contributor
timestamp: November 16, 2024, 10:10:54 pm
content: Oh boy, i just made myself a DIY prototype of those. Since i might probe half a dozend pins, i thought: "damn that should be possible to be made cheaper", and so i just held my mouse over the "pay now" button, and started thinking.After watching the video again, it didnt take long for me to DIY a prototype, and it works as good as those. Since my idea will affect their profit big time, i am not gonna post this here yet, as this is a really good idea, and should bring them some money.Its just for for the folks, that dont have much money: It can be done pretty cheap! A pogo pin is not even needed!

author: shabaz
author_rank: Frequent Contributor
timestamp: November 16, 2024, 10:39:56 pm
content: A couple of ideas for probing (won't be suitable for all scenarios).I used steel wires for probing I2C in the first photo. Since it's not easy to solder to steel, I used a ferrule on it, at the PCB end.The other photo shows thin coax (RG-178) with a ferrule around the braid (ferrules are great problem-solvers!). The blob contains an 0805-sized 950 ohm resistor. These probes can be used as solderable probes (tack the ferrule to the ground plane, and then solder the short colored wire to the signal of interest.But, despite these methods, I still also find the Sensepeek probes useful (and they are sometimes discounted on their site, and don't cost much more than normal 'scope probes; I saved a bit of money and didn't buy the kit, and used my own metal base and board clamping methods).

author: eTobey
author_rank: Super Contributor
timestamp: November 18, 2024, 08:03:42 am
content: What ferrules and tool did you use for the steel wire probes? Did you really just wedged them blunt wires on the chip?

author: shabaz
author_rank: Frequent Contributor
timestamp: November 18, 2024, 10:00:35 pm
content: I used the type of crimper shown in the photo, I used a Knipex one, but there are many lower-priced alternatives in the same style, for about 15-30 euro on Amazon/AliExpress etc, and I think they will be just as effective for this purpose.The ferrules are extremely low-cost. A pack of 100 should not cost more than 1-2 euro max even when purchased from a normal electronics distributor.As you say, the steel wires are just wedged against the chip. I didn't sharpen them, they were cut with wire-cutters. It takes a bit of care to position them (need to do that with the circuit powered off), but they don't move out of position afterwards.

author: eTobey
author_rank: Super Contributor
timestamp: November 19, 2024, 09:27:45 am
content: Those crimp things (ferrules? - see picture) dont look like beeing crimped with that tool.

author: shabaz
author_rank: Frequent Contributor
timestamp: November 19, 2024, 12:01:18 pm
content: I thought I had used that crimp tool, but well spotted, I usedKnipex 97 53 08for that. It produces this more unusual indentation.I did that for no particular reason that I can think of. Both tools will be fine for this purpose. Possibly that the tool was nearby at the time. I prefer the other type of tool most times however.