Re: P6137 scope probe repair

Tom Lee

The cable is replaceable (I think you've seen this already, since you've disassembled it). The hard part is finding a good cable at a reasonable cost.

Does the cable show any obvious signs of damage?

If the break is at or near one of the ends, that's fixable. If it's somewhere near the middle, it's probably a lost cause, if you want to maintain a clean response.

If there are no visible cues as to where the break is, you've got a little extra work to do. If you have access to a TDR, you can pinpoint the location of the break easily. In the absence of a TDR, you can still find the location with surprising accuracy from two good capacitance measurements: Suppose the total cable length is L, and one segment is of length x1 and the other is x2. If the capacitance looking into x1 is C1, and that into x2 is C2, then x1 = L [C1/(C1 + C2)]. If you're lucky, you'll find that one of the capacitances is very much smaller than the other, indicating that the break is indeed at or near the ends.

All this assumes, of course, that you have definitely isolated the cable in determining that the cable, and not something in the compensator box or connections to it, is truly broken.

Good luck!

-- Tom

Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070

On 1/16/2021 00:48, Jared Cabot via wrote:
Hi all,

I recently picked up a P6137 scope probe for a song and thought I'd try my luck.
Predictably, the center conductor on the cable is open circuit..... Is there any way to repair or replace this cable with a new one? I have it apart now, but is there some sort of cable I can use as a replacement?


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