MDPC CTX3: A load of doubtful marketing bollocks lands on my crimp connectors page

I promise the day will come when I stop banging on about crimp tools, but, indulge me just one more time. Somebody just posted a link to the below crimp tool on my crimp connectors page:

MDPC CTX3 Crimp tool: £55. Like a well choreographed cooking channel, it’s pictured on wood. Hoping to invoke a woody reaction among prospective purchasers. Source:

Website link. It looks rather like a re-badged IWISS SN-28B to me, for double the money.

IWISS SN-28B. Made in China, £25 and common as blow-flies.

Thier website is loaded with incredible assertions (quoted):

“The MDPC “10th Anniversary Edition” crimping tool MD-CTX3 replaces the legendary CT1 model, which earned the reputation of being the reference for the last 7 years.”

I was not able to find any pictures or references (other than that statement) of the fabled “CT1”. Unexpected for a tool that’s been around 7 years? As for it being a reference – A reference crimping tool can only ever be the connector manufacturer original tool, which can cost hundreds to even over a thousand dollars, and for a good reason. I have detailed many of these (all of the relevant tools for PC modding) on this page.

“5-axis CNC shaping of the essential structures, made in Germany, to achieve the highest standards in crimp terminal shaping over all 3-axis (!) of the crimp terminal – based on the official MLX guidelines.”

Made in Germany? It seems rather improbable that two nearly identical looking tools would be made in both China and Germany. I have many German made crimp tools in my collection, the cheapest retails for over £300.

MLX guidelines? Let’s google that shall we…

A highly scientific looking diagram provided by the marketer. Must stick out? You’d bloody hope so. Even if it does, you haven’t scratched the surface of crimping considerations. Note to the knuckleheads who produced this graphic: The “Top” is called the Crimper and the “Bottom” is called the Anvil. The “Rear” is the wire die, and the “Front” is the insulation die. Source:

If you’d like to learn some actual science about crimping – take a look at this video:

A further note to PC modders

I recently looked at a new tool from IWISS – the SN-025 which actually does a better job at crimping the main two types of connector used in PCs (DuPont / Mini-Fit Jr), than the IWISS SN-28B (and by extension, the illustrious MDPC CTX3).

It is not suitable for crimping Commercial Mate-n-Lok terminals or look-a-likes. You will still need the SN-28B for those, but I wouldn’t imagine many are used anymore. Having not purchased the CTX3, you’ll be able afford both, with money left over for a couple of beers.

An easy to build MCS-48 programmer, and something to use it for

Recently I’ve been working on a new shield for my HVEPROM project to program internal ROM UV erasable versions of Intel’s first microcontroller, released in 1976. I built it because I was trying to repair something with one of these in it, and being able to disassemble and modify the code was a key part of that repair. My universal programmer (quite an expensive one) didn’t support these. Others do, but I wasn’t keen to go splashing out again.

Read more about it here.

Why stop there? Having gone to all that trouble, I thought it’d be interesting to build an entirely new project based on one of these, and see what they’re all about.

Pictured above is the result of that effort. An MCS-48 based dual temperature sensor. It uses one or more DS18B20 one-wire bus temperature sensors.

Read more about it here.

IWISS SN-025: Another head scratching “DuPont” crimp tool lands

Following on from my recent review of the Preciva PR-3254 crimp tool, I hit up eBay and Amazon to see if any other such tools may have surfaced lately. I found one:


We have a new tool (Amazon UK link), which is also apparently specifically designed for these terminals. At the time I wrote this article, the SN-025 is not (yet) listed on IWISS’s website?

Two terminals apparently crimped with the IWISS SN-025. A “DuPont” terminal, and, err, what’s that other one? One auction listing mentions TE “Superseal” terminals, which look quite different to the one on the white wire. Recognise it? please drop a comment.

The above graphic is provided by the Amazon seller, specifically pointing out that it wraps the insulation around the wire. It’s almost as-if they’ve been reading my crimp connectors page

While this is being sold as a “DuPont” crimp tool, it appears it is predominantly designed for another type. It has three dies:

  • AWG 28 for “DuPont” terminals?
  • AWG 20 for mystery larger terminal
  • AWG 18 for mystery larger terminal

The AWG 28 die

DuPont HT-95. The gold standard which I’ll be comparing against.

Let’s put some “DuPont” terminals in there and see what we end up with:

Of course SN-025 wasn’t going anywhere near the HT-95’s crown as ultimate “DuPont” crimp tool but it did do marginally better than the Preciva PR-3254 I reviewed previously.

The SN-025 not having an AWG 24 die, it over-crimped the insulation as we would expect, and the wire part isn’t crimped anywhere near as tight as it is supposed to be – typical for Chinese tools.

Verdict: Pass (for non critical applications).

If we were to cut open the wire parts of the DuPont vs IWISS crimps, we would find something like this. For the SN-025, likely a lot worse. Source: TE Connectivity

The other two dies?

I went through my crimp tool cupboard to see if I had any others like this. Of the, err, considerable number (I’ve lost count) of manufacturer original tools in my collection, just seven have an ‘O’ type insulation crimp. Only two of those were in this wire size range:

Top: TE Multimate crimp tool. Bottom: TE Economical Interconnect crimp tool

TE Multimate

An interesting type to compare against because Multimate terminals look quite similar to the one pictured in the image the tool is sold with. This tool may be designed for use with a similar type of connector of Chinese design/origin. Given how esoteric these are, no point in going any further into that.

Economical Interconnect

A common type stretching to AWG 20 wire size, which has an ‘O’ crimp. More about these here.

KK .396 (?)

Lost in translation? The range of terminals apparently crimped by this tool. Always good to have something to handle those Micro Timers.

In addition to the “DuPont” types, Molex KK .396 (.156″) is offered as a supported terminal type. Not something the average hobbyist is going to be reaching for. I’ve got the manufacturer original tool for these, it’s not quite an ‘O’ type crimp, but let’s give it a shot anyway:

Mini-Fit Jr (?)

The die in the manufacturer original tool is quite similar to the KK .396 tool, so we’ll look at these too.

Certainly not one for E.I. It was OK on the wire part but it didn’t touch the insulation crimp. Verdict: Fail.

For KK .396. Pretty good! the insulation part is a tad too loose on AWG18 wire (forget it for AWG 20). The results do not match the marketing image, I can only assume that was done by a different tool. Or, perhaps, the marketing image is depicting a smaller KK .254 terminal? Verdict: Pass.

Last but not least, it did a really good job on Molex Mini-Fit Jr. I’m so impressed with the results that I’ve decided to take a closer look:

AWG 18 wire crimped by 3 tools. On the left a typical result of a budget tool, with the insulation deeply pierced due to the very long tabs on these terminals.

For the SN-025 crimp on the right: It takes a bit of practice, and I’ve accidentally nicked the wire because I positioned the terminal too far forward, also the AWG 20 die must be used. The SN-025 has yielded a result very similar result to the Molex 63819-0900, correctly and cleanly wrapping the insulation support. The best I have ever seen from a budget tool.

Verdict: Pass.


Without a specification from the manufacturer, and subsequently knowing what it was actually designed for it’s difficult to give it a final judgement. Wire crimping force is quite respectable for larger terminals i.e. KK.396 / Mini-Fit Jr, but not so great for “DuPont” terminals.

As always my recommendation is that this tool (and any other tool in this price bracket) should only be used for applications in the “fun” category, specifically the kind of fun that doesn’t involve someone losing an eye when it goes wrong.

Manufacturers of tools around this price do not spend any time ensuring that the tools they produce crimp terminals to the specifications of a specific type, instead they are a broad brush design intended to crimp a range of terminals to a vaguely presentable standard. Yes we’ve got some nice crimps on Mini-Fit Jr, but that is purely luck, and only achievable with very specific terminal placement during crimping.

If you’re building something critical and/or expensive, name brand terminals and the manufacturer tool should be used. I have detailed a lot of these on this page.

A new budget “DuPont” crimp tool is bought to my attention

Preciva PR-3254 crimp tool

Back in 2015 when I first wrote up my crimp connectors page. I pointed out that there was no cheaply available tool which could crimp “DuPont” terminals properly (cheap Chinese connectors which resemble DuPont’s Mini-PV connector).

Crimped Mini-PV Terminals
Crimped Mini-PV look-alike Terminals

At the time pretty much all tools in the $30 or less price bracket got you a result like on the left, because the insulation crimp die was a ‘B’ shape when it needed to be an ‘O’ shape.

Comparison of the DuPont Mini-PV crimp tool, and the die of a typical budget tool

Anyway… onto the tool in question. This was bought to my attention by a reader, and it’s actually sold in a kit (Amazon UK / US). It’s very affordable and it’s got a die specifically designed for “DuPont” terminals. My first reaction: Wow. The bounty for such a tool has been out for 5 years now. Could this be the one?

First impressions unfortunately weren’t particularly good.

PR-3254 “DuPont” die compared to DuPont HT-208 (AWG 24) die

When the die is fully closed, it ends up with an uncomfortable “oval” shape, rather than the circular shape all DuPont original tools have. You cannot partially close it either because the wire part wouldn’t be crimped at all.

Top: AWG 24 wire crimped with PR-3254. Bottom: AWG 28 wire crimped with PR-3254

Results aren’t too bad. It’s doing the right thing, wrapping the insulation crimp instead of making a mess of it. For AWG 24 wire, there’s far too much force on the insulation, crushing and damaging it, but the wire part is reasonable.

For AWG 28 wire, force is about right on the insulation, but there’s not enough force on the wire part. In the long term, moisture may get into that and cause troubles. You could double it over to mitigate this to an extent.


It’s very encouraging to see a budget tool specifically designed for these terminals.

It does so-so job of AWG 28 on “DuPont” terminals. Its other dies are fairly standard and ones like it are found in other tools, for example the IWISS SN-2549. Don’t go rushing to buy it. I’m looking at another tool at present which may be a little better than this one.

This tool is probably OK for people who are building temporary/non critical things, however ultimately this particular effort appears to have stopped for a cigarette just short of the finish line.