Tek 24XX Series BNC replacement

[Fractal]

I just copped a 2565 locally but once again, a common issue I've found with old test equipment in Taiwan appears to be the BNC plugs getting oxidized over in this tropical environment.

After spending 2 days in the ultrasonic bath it removed most of the shmoo, but the inner pin and outer surfaces remain significantly oxidized.

I was able to read a part number; 28JR270-01, which appears to be a Tek proprietary part - couldn't find any source



I've found a couple plugs at my local electronics shop, thinking the isolated part couldn't be that complicated and I could hack something up, but I don't get how to get the 3rd pin to work

It appears to me that:

1- The signal pin goes straight through
2- The ground goes from the outer ring through the chassis - solder pins are unused
3- The 3rd pin "Probe-Coding Ring" according to the service manual

A probe-coding ring around the BNC input connector
passes probe-coding information (a resistance value to
ground) to the Analog Control circuitry for detection of
probe attenuation factors. The readout scale factors are set
to reflect the detected attenuation factor of the attached
probe.

How is it connected within the connector? is it just an inductive ring isolated from both signal and GND?

Are there any cutout views on how to reproduce it?

Or any effective way to restore a worn-out BNC?


Any tips appreciated!

[calibrationfixture]

Hi Fractal,

The Tek PN is 131-0679-02.

Manufacturers:
- Specialty Connector      : 28JR270-01
- Kings                           : KC-79-186
- Tajimi Electronics Corp. : BNC340-BR-1

Succes,

Calibrationfixture

[Wallace Gasiewicz]

The Probe Coding Pin just goes to the probe part that connects to the scope. Inside the little probe adjust box, there is a resistor to ground.  So not reactive, just a DC signal.
The resistor in the probe will be different for each type of probe. 
e.g different for a 1X, 10X and 100X probes. This makes the scope able to tell which probe is in use. The probe 10X is calculated into the display. That is if you use the probes with the pin.
A 10X probe without the pin would probably be taken as a 1X probe so the waveform displayed would be 10 Times Smaller.
That is pretty bad corrosion, if you have nothing to lose, try Vinegar soak. or another acid.I do not think any of the commercial electronics cleaning sprays would help.