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I have a board fitted with a 10-way 3.5mm screw terminal in a similar style to what you see here (GSO14V-3.5):

dimensional drawing from the linked PDF

I am after a reliable contact to four of these points for testing purposes, without unscrewing and screwing the terminals each time - there are no other test points available on the board. Terminals are pre-screwed in. Currently, four solid wires are used with a rotational force applied to try and force contact - but this has not resulted in a reliable connection thus far.

My initial thoughts are inspired by a pair of C-clip pliers, e.g. an externally contacting test clip - squeeze to pull the halves together, release and they spring apart, then produce a jig to position the four required together. Alternatively, I can envisage a formed wire piece which performs the same external spring function and press fits into the receptacle.

I cannot however find either such product on the market, is anyone aware of such a device in test-clip sized form, or, does anyone have a better solution?

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  • \$\begingroup\$ I am not 100% sure what you are asking, but you can probe the screw itself usually with a multimeter or scope probe. So you could make a 4 headed spring pin probe to contact 4 screws. \$\endgroup\$
    – tobalt
    Commented Jun 9, 2023 at 8:53
  • \$\begingroup\$ Probing the screw does work providing the terminal is screwed in, I would like a slightly more permanent solution though which can be simply located and left for 30sec or so \$\endgroup\$
    – Sam
    Commented Jun 9, 2023 at 8:55
  • \$\begingroup\$ @Sam then why not screw in and out? That sounds easy and quick enough for 30s. \$\endgroup\$ Commented Jun 9, 2023 at 9:28
  • \$\begingroup\$ (But tobalt's spring-loaded probe approach is the professional approach to probing most things; a spring-loaded probe together with some probe holder. There's many ways a probe holder can be built, but the first thing my search engine gave me looks like this and I think that well illustrates the idea) \$\endgroup\$ Commented Jun 9, 2023 at 9:35

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You could build an adapter with spring test probes that make contact to the bottom of the screw terminals.

enter image description here

enter image description here

Source: www.testprobes.nl (not affiliated; we're using a different brand)

Depending on your budget and the number of devices that need to be tested, this investment could be worth it.

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    \$\begingroup\$ I had always wondered what these concave head types would be good for ;) \$\endgroup\$
    – tobalt
    Commented Jun 9, 2023 at 10:43

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