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Hi all, I need some help to identify these probe tip parts, and more important, to identify the probe type they belong to.

I am organizing my probes, and also checking calibration on them, but now I found the following:
I have three P6133 probes, one of them is missing the probe tip, I also have two P6137 probes, they both work fine.

By fine I mean: proper attenuation and rise times, these are the probes having the black tips installed.

And now the weird thing: none of the probes with the grey tips installed will work at frequencies higher than 10-20kHz?!?

All probes work great -both the P6133 and the P6137- , both frequency and rise times, but only when the black-tips are used.

All tips measure 9 MOhm and have no resistance to ground.

Is it possible the grey tips are broken?
Do the grey tips belong to another type of probe?

Can somebody shine some light on this?


Update:
To partially answer my own question:

In the pictures I show how the interior of the broken probe tip assy looks like.
My guess is it was exposed to some too high voltage while the input was at 50 ohm? Who knows...

Anyway: I have 3 P6133's, these tips are probably unobtanium or super expensive... :-(
If somebody know if these are still available, please let me know.

Pictures can be found here:

/g/TekScopes/album?id=272613

Saludos,

Leo

P6133 has 3 different tips depending on cable length 1.3m, 2m, 3m, part # 's 206-0265-10/12/11 P6137 tip is 206-0378-00.
Jeff

Both the color of the tip and the tail matter. See here for an overview of tip colors for the various probes:

Tip clear, tail natural would be for the Opt. 25 P6133 (with 1.3m cable), a P6133 with 3.5 mm probe tip (as opposed to the standard 2.5 mm tip). Tip black, tail natural would be for the P6137. Based on that, it seems like these should be the correct tips for those probes. The only thing I can imagine is maybe the probe tips were damaged somehow. I would expect the hybrids to be a parallel RC combination, as described in the "Oscilloscope Probe Circuits Concepts" publication from 1969. Do you have the ability to measure the capacitance (~10 pF) in parallel with the 9 MOhm resistor? I wonder if that capacitance became open somehow.

It think the capacitor might be formed by the probe tip / center conductor, dieletric around the probe tip and the grounding sleeve. If that is true, then a bad connection between the ground of the probe and the metal around the probe tip could be responsible for the behavior you're seeing.

Add option 25 tip 206-0393-00.
Jeff

--
Jeffeelcr

Thanks guys,

it's past midnight now here in Spain, but will look into it tomorrow.

Leo

Hi all, thanks for the information provided.
I decided to modify the P6133 probes into 1x probes:

I opened both the broken probe tips, and replaced the burned hybrid with a zero Ohm replacement. I used a hardened, gold plated wire wrap pin and used heat shrinking tube to isolate and center the replacement inside the tip housing.

To make things complete: I switched the BNC parts of two P6122 I had -these did not have the readout pin- with the BNC part of the modified P6133. Now they both report the proper probe type to the scopes that support readout.

Saludos,

Leo