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I am working on a tek 371 with a friend of mine , it has no test fixture and these things are never seen on ebay , so our idea is to make one . We are in the process of using a test fixture which will be modded to house a transistor with sense leads .

I am wondering that because this is a high current and high voltage setup what would be an appropriate wire in addition would the length be critical for accuracy, i do not have a unit to look at so i assume all as it relates to designing on that will perform well .
If someone has some experience with this unit could you chime in and explain as much as you can , or if pictures are possible of the inner workings that would help. Thanks .

Oliver,

I have uploaded some pictures to the Photos section.
A few notes:
The fixture pictured is missing the clear safety cover.
There are three microswitches in the fixture; two in front that are actuated when the cover is closed, and one at the hinge that is actuated when the cover is open.
There is a 10nf cap connected as shown in the main housing.
The resistor shown in the removable section is 1k.
There is a schematic in the 371A service manual available at Tek.co, and on the Tek wiki.

Hi Bob??Thanks for your reply that you sent to me with pictures I would like to ask you if you could possibly let me know the gauge of the wires there and the possible length of the cord coming from the plug that goes to the Tracer to the test fixture. Once again thank you Neil
On Sun, Nov 4, 2018 at 6:07 PM, Bob Koller via Groups.Io<testtech@...> wrote: Oliver,

I have uploaded some pictures to the Photos section.
A few notes:
The fixture pictured is missing the clear safety cover.
There are three microswitches in the fixture; two in front that are actuated when the cover is closed, and one at the hinge that is actuated when the cover is open.
There is a? 10nf cap connected as shown in the main housing.
The resistor shown in the removable section is 1k.
There is a schematic in the 371A service manual available at Tek.co, and on the Tek wiki.

I am not familiar with the 371 or its test fixtures, but I have some experience that may help:

At Teradyne (in the 70’s), the discrete devices test equipment operated with kelvin connections out to the leads of the device under test - all the way from the instrument innards to the contacts on the device under test.

For each lead (collector, for example) there was a “force” lead and a “sense” lead. The maximum current might have been 10 amperes - memory of this detail has faded. The wires within the system out to the connectors for the test fixtures may have been No. 16 or 18. (They were teflon, for leakage control under low current test conditions.) That’s for both force and sense. The tests occurred in very brief pulses, maybe on the order of 5 milliseconds. The currents in the 371 may well be of longer duration, and also repeated for a series of base currents, for instance. So larger conductor size may well be needed.

If you can examine the wires out to the test fixture connector, this will tell you what size wire to use, I think.

A further note on test fixture connectors - most of them were made of diallyl phthalate. This stuff is blue, rather costly, and needed for extremely low leakage.

I look forward to your success.

Roy

On Nov 2, 2018, at 9:04 PM, oliver johnson via Groups.Io <nojjamaica@...> wrote:

I am working on a tek 371 with a friend of mine , it has no test fixture and these things are never seen on ebay , so our idea is to make one . We are in the process of using a test fixture which will be modded to house a transistor with sense leads .

I am wondering that because this is a high current and high voltage setup what would be an appropriate wire in addition would the length be critical

Roy Morgan
K1LKY since 1958
k1lky68@...