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!