Sunday, 7 September 2025

Logic analyser replacement clip leads

I sometimes wonder what exactly the manufacturers of logic analysers and the like think that people user them for. I have seen several come with leads like this with quite large clips on.

Or worse, this set with all black wires and even larger clips.

Side note, back in the 80s I knew someone who fitted car alarms. They all came with bundles of multicoloured and neatly labelled wires to make installation easier. He pointed out it also made it easier for a thief to disable it (cut the red wire .... no the green ...), so he would pull out a massive reel of black wire and use that for all the connections instead.

Those sort of clips only seem to fit if you have a large pin and lots of space around it. No chance of getting an IC or component leg.

Like the standard oscilloscope probes, they seem to have been designed in the era of point to point wired valve amps where there were lots of suitable points to clip onto large component legs in free ait, and they don't seem to haven't updated the design since then. Similarly a lot of the time I would like one or both leads on my multimeter to have clips rather than probes.

It is rare I can justify enough space for large enough test points on my designs.

If you are lucky, the connections to the analyser are standard connector types (e.g. 0.1" pin headers), so you can make up your own cables.

I have built up custom cable sets for common tasks (at least for me), such as monitoring the output of the video connector on a PET or Mini PET.

I originally bought the Ika Logic SQ200 4 channel unit to finish off development work on the original Mini PET.

It is still going strong doing the same job on the Mini PET II five years later.

Useful for sorting out things like the rather convoluted composite video specification.

And the very non-standard PET 9" monitor drive.

This has out-survived several more capable units. I am now back to something with more channels, but more on that later (in short, it's brilliant).

In previous posts you may have noticed the cabling was a bit of a mess as I was using various assorted leads with the wrong colour clips. Many of the better ones are still clipped to the plethora of unfinished projects I have.

So to get around that, I decided I should finish lots of those projects.

....

Yeah right.

This is me you know.

So, I did the right thing, and bought some new clips. I like these E-Z-Hook Micro Hooks. #NotSponsoredWishIWas

I also decided to get some nice wires to go with them. These ones were a bit pricey, but they are the more flexible silicone (?) types which are lighter and less likely to weight down the connections and should fit the hooks well (I have found some connectors slip off and whatever they are made of is impossible to solder to - maybe I need one of those battery terminal welder things?)

Since I am northern, I went for the 24" lead set, which was the same price as the 12" lead set (you often tend to pay per terminal for this sort of thing, rather than lead length).

My plan was to cut the leads in half, so I get the nice leads with the heatshrink end for the clips, and I can just wire on a standard Harwin M20 5 way connector at the other end.

I find it easier to stick with that one brand so all the crimps and shells match. You can get various random versions from ebay and Ali Express, often referred to as "Du Pont" connectors some of which seem interchangeable, other of which are not. In the same way, I stick with Molex KK and JST VH series rather than random clones. Your mileage may vary, I'll stick with my Harwin M20s. #NoSponsoredByAnyOfThemEither

I started with the four way analyser. That's looking very nice and colourful.

That plugs neatly into the analyser on the right.

My only gripe is the leads are organised on the box with green, red, yellow, blue, but in the software, the order is reversed and blue, yellow, red, green.

These clips are much easier to use on IC legs etc.

The softer wires also sit more easily, hopefully less stress on the connections.

Well, that's looking good, time for the 10 way set.

Cables cut and crimped.

Probe clips installed.

Ready to go.

The eagle eyed among you might think I have wired that up wrong, but like the other one, the pin order is not what I expected.

I initially made a test set with old leads, wired as below. If ground is the right hand pin, that should be the black wire, and so logically, the wire next to it should be brown, the red, and so on, in the standard resistor colour code (albeit backwards).

But that is not the case, channel 1 is actually far left.

You actually have to wire it 1,2,3,4,5,6,7,8,9,0. It sort of makes sense to have the black next to the channel 9, which is sometimes used as the external clock, so would be the highest frequency signal?

That way you match the colours of the wires, the signal traces, and the clips.

Even more wires to clip on now.

The new clips are great for clipping onto IC and component legs.

I am making lots of use of the external clock option, I have chanel 9 (scorchio) wired up to the 6.5MHz clock, so everything is displayed in terms of pulses of that clock.

Very useful for things like checking the critical 8 cycle per character timing.

The smaller units still gets a lot of use, and did great service with all the ZX81 BASIC for Minstrel 4th and Minstrel 3 testing.


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