Keithley 1488 low thermal shorting plug (a quick teardown)

[lowimpedance]

 Found this little accessory while tidying up and though hmmm lets look inside... .
And what do we see, well not much as to be expected.
The plug part is a ITT Cannon (AN3106 !) connector used on various vintage Keithley instruments such as 147, 148, 181, 150b etc.
And of course its a crimped connection.
The back shell/housing/cap, call it what you like is a rather substantial thermal mass aluminium 'cup' filled with foam which is now disintegrating with age.
 And that's it...!
 I did say a quick tear down.

[VintageNut]

I have one of those as well and use it with my 147. They work very well for the intended purpose.

I think that the standard version of this plug does not have copper pins.

[lowimpedance]

 Ah yes these plugs look like they have gold plated copper pins.

[macboy]

Ah yes these plugs look like they have gold plated copper pins.

Perhaps copper-beryllium? Pure copper is very soft as you know, making it unsuitable for connectors - it would wear out in just a few cycles. Adding as little as a fraction of one percent Be can make it literally as strong as steel, although many times the cost, and potentially toxic as well. I think that Cu-Te alloys are similar (and even more expensive) but might have better thermoelectric properties against pure copper than the Cu-Be alloys. I have looked for but haven't found data to back that up.

[VintageNut]

Ah yes these plugs look like they have gold plated copper pins.

Perhaps copper-beryllium? Pure copper is very soft as you know, making it unsuitable for connectors - it would wear out in just a few cycles. Adding as little as a fraction of one percent Be can make it literally as strong as steel, although many times the cost, and potentially toxic as well. I think that Cu-Te alloys are similar (and even more expensive) but might have better thermoelectric properties against pure copper than the Cu-Be alloys. I have looked for but haven't found data to back that up.

Good points. There appears to be no publicly available description of the chemistry of the copper in this plug.

Stress on the copper of this plug is much less than any low thermal banana. The copper is embedded in what looks like a plastic/teflon molded plug. There is a key in the plug that guides it into the socket/jack of the nanavoltmeter. It would be difficult to stress the copper during normal insertion of the plug into the nanovoltmeter. The plug and jack are designed so that the plug can only go straight in and come straight out.