Tips for Soldering 4 Pin Mini DIN USB Cables

  • Thread starter Ephant
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  • #1
Ephant
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4 pin din usb.JPG


I'm looking for a USB cable with 4 pin mini DIN like the above with the normal other end to PC. But I couldn't find even one selling it. They only have the 4 pins mini DIN not equal distant or like the following:

din plugs.JPG


Have you not seen anything like the 4 pin with equal distance? Why is it so rare? Where to find it and included in USB cable like the following selling me for $400. I find it so expensive.

usb cable.jpg
 
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  • #2
What is it used for? That might help in your search.

At first I thought it looked like the connector for my marine radio but I think whatvyou have is too small
 
  • #4
Is there only one pip, to index plug rotation, on the outer surface of the metal housing?
What is the exact outside diameter of the metal housing that enters equipment?
Can you measure an inside diameter of the metal housing?
 
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  • #5
Baluncore said:
Is there only one pip, to index plug rotation, on the outer surface of the metal housing?
What is the exact outside diameter of the metal housing that enters equipment?
Can you measure an inside diameter of the metal housing?
Yes, a better drawing please.
Probably Kycon KPPX-4P
 
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  • #6
Baluncore said:
Is there only one pip, to index plug rotation, on the outer surface of the metal housing?
What is the exact outside diameter of the metal housing that enters equipment?
Can you measure an inside diameter of the metal housing?

I don't own the equipment yet. Here is how the usb socket looks like.

usb socket appearance.JPG
 
  • #7
Look up '4-pin M-DIN DC-power connector' or '4-pin power-din connector'

There are plenty of variations with thin and thick pins varied, or with slightly asymmetric placements, so you might not get the right one for first try but the product exists and available from bigger distributors (Farnell, Digikey, Mouser and such).

Ps.: you can also look for DIY solutions (with the type of connector mentioned) based on the device it'll be used for. If you are not familiar with the connector-jungle then this might be the best solution.
 
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  • #8
Google; circular USB connector 4-Pin Lemo
 
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  • #9
Indeed, that is a Lemo connector so won't follow a DIN standard
Lemo is the name of well-known company that makes connectors that are frequently used on measurement equipment.
There is also a competing company called Fischer which makes very similar connectors, but I am pretty sure that is a Lemo
 
  • #10
Your situation is probably exactly what the manufacturer intended: Take a 'standard' cable and change it so that most people will have to buy it from them.
 
  • #11
Lemo connectors are never cheap but they are also very rugged and work well, meaning in many applications they are worth the price,
A simple 4-pin one shouldn't be too expensive and standards models are widely available. If you know how to solder you might be able to take a standards USB cable, cut off one end and replace it with the Lemo.

Note, however, that you need to pay attention when ordering the connector since they are highly customizable (by combining different connector parts); this is probably an off-the-shelf model, but if not you will need to spend some time browsing the Lemo catalog.
 
  • #13
I found out the exact LEMO model that will be compatible is the LEMO FGC.0B.304 but I can't find stocks of this anywhere. Not even Digikey has this. Where else can you order these? At LEMO, they ignore any quote for simple item because they think it's not worth the hassle.
 
  • #14
  • #15
It's FGG.0B.304. Not FGC
 
  • #17
Ok. Found it.

A question. If you will cut a USB cable in half. The wiring is so thin or not solid enough to be soldered. What kinds of wiring is this?

How do you find USB cable with wiring that is solid enough to be soldered?
 
  • #18
if you can'f find one, you can buy USB cables with bare wires at one end.
Search for "pigtail USB"
 
  • #19
The Ebay seller refunded me the money saying the model I need is already obsolete. So I have to source it from LEMO clones in china.

lemo connection.JPG
For those with experience using LEMO or ODU clones from China. What is your comment about them? Are they identical to LEMO or are the pins not aligned or the keying not in exact angles, etc.?

Also for size OB with housing diameter of 9.5mm (0.374") and pin size of 0.7mm (0.2756"). Let's say there are 4 pins. How easy it is to solder them? Should you match the wires size to the pins? What happens if the wire is bigger or smaller? And if a pin made contact with the metal and shorts the housing? What would happen? How easy it is to do the accidental shorting for those average users?

Also in the China clones. What sizes of wires are the pins designed for?

Lastly. What kind of soldering iron must you use? Without any experience, how successful would connecting one be especially if they are LEMO clones. Would the clones make it easier or harder?

Thank you.
 
  • #20
Ephant said:
What kind of soldering iron must you use? Without any experience, how successful would connecting one be
The description I saw on LEMO connectors was they use crimp pins. That is the large end of the pin has a blind hole along the pin axis.

The assembly process is to strip the correct gage wire, insert wire into hole in pin, then crush the pin using a special crimp tool. "Crush" in this case is to squeeze the pin like you would squeeze a hose to stop the water flow. This traps the wire in the pin, and if done correctly results in a gas-tight connection, almost a cold weld.

Soldering is an option, but takes a small tip on the soldering iron, fine diameter solder, and much experience.

For instance, in most (all?) crimp connectors the wiring end of the pins fit in a recessed hole in the connector shell. If you get solder on the outside of the pin it will not fit in the connector. If you know anyone who is well experienced with soldering small parts, get them to do it; whether by begging, paying, coercing.

It is possible to use pliers to crimp the pins but quite difficult to get it correct; better have a bunch of spare pins.

Good Luck!
Tom

p.s. Is there any chance of replacing the mating connector with something that is more available and easier to use? That's probably worth spending some time researching.
 
  • #21
Tom.G said:
The description I saw on LEMO connectors was they use crimp pins. That is the large end of the pin has a blind hole along the pin axis.

Lemo makes many different types of connector. While I do believe crimp versions are indeed available, there are certainly types meant to to be soldered as well. We use Lemo connectors a lot (the original, not clones) on our kit and I don't think I've ever come across one that was crimped (but again, I do believe they exist).

A standard four pin lemo isn't very difficult to solder (back when I was more involved in the work in the lab I on a few occasions had to solder Lemo connectors with more than 20 pins...that is more complicated but still doable); it is not any harder than soldering say a DIN or D-sub connectors (although the pins are a bit close together). You don't need any special equipment; although a magnifying glass or similar can be useful to check for shorts etc.

Note that you should ideally match the options for the type of connector you are using to the cable used (each type of connector comes with different options for strain relief etc; there is a reason why the model numbers are so long); if you try to use a cable that is too thick or too thin for the strain relief the connector won't won't be mechanically stable (or won't come together at all). It might still work electrically, but there is a good chance it will break if the solder joints is the only thing holding it together.
That said, I have cobbled together solutions using heat shrink etc (to increase the diameter of the cable) that have worked OK.
 
  • #22
CRIMP 4.jpg


crimp 1.JPG
crimp 2.JPG


Notice the wings of the pins. If they are not properly situated in the connector and you push against the socket pin in the equipment and the pin got push out backward, what would happen? But then isn't it the connector housing has retention screw at the back that can prevent the pins from moving backwards? This is my primary concern about the crimp connectors besides how to crimp it using long nose pliers. Yes, can you just use long noise pliers in crimping it and not investing on $500 crimping tools for just one project or crimping job?
 
  • #23
Are you sure you can't find the solder version (where the pines are already fixed to the connector)?
They are definitely available (I have soldered many, many 4-pin Lemo connectors from various series over the years). That said, I understand you are looking at clones, so maybe they don't do solder connectors?
"FGG.0B.304" is just the first half of the part number, the full number includes a bunch of letters etc and one of these letters specifies if it is a crimp or solder connector. Again, see the Lemo multipole catalogue

I my experience, using anything except the correct tool for crimped connectors is not a good idea; you often end up with bad contact between the wire and the connector and/or pins that keep getting coming loose
Also, if you are using crimped connectors it is vital that you use the right wire diameter or it won't work regardless of the tool you are using.
 
  • #24
Ephant said:
can you just use long noise pliers in crimping it and not investing on $500 crimping tools for just one project or crimping job?
Usually, crimp pins can be soldered with some practice. As long as there is no solder on the outside of the pin, they will fit.

Crimping provides uniform result even with low skill, while acceptable soldering requires practice => in the industry, crimping won. But soldering is still valid.

But, doing crimping with common pliers is a hack at best.
 
  • #25
f95toli said:
Are you sure you can't find the solder version (where the pines are already fixed to the connector)?
They are definitely available (I have soldered many, many 4-pin Lemo connectors from various series over the years). That said, I understand you are looking at clones, so maybe they don't do solder connectors?
"FGG.0B.304" is just the first half of the part number, the full number includes a bunch of letters etc and one of these letters specifies if it is a crimp or solder connector. Again, see the Lemo multipole catalogue

I my experience, using anything except the correct tool for crimped connectors is not a good idea; you often end up with bad contact between the wire and the connector and/or pins that keep getting coming loose
Also, if you are using crimped connectors it is vital that you use the right wire diameter or it won't work regardless of the tool you are using.

I just want to connect a USB 2.0 male to a LEMO end with the following pinouts:

USB-LEMO pins.jpg


We can use this LEMO connector at ebay:

https://www.ebay.com/itm/1857041650...tFD7v525PAm4OeN+1J9fkfZQ==|tkp:Bk9SR9rgxYmfYw

FGG.0B.304.CLAD52Z.JPG


My soldering is very poor. This is the best I can do for a dc jack. Can anyone please help me solder the USB 2.0 cable to the LEMO?

dc jack solder.jpg
 
  • #26
Soldering the 4-pin connector shown in the photo isn't very difficult, it is literally the kind of thing I would ask summer students or new Phd students to solder as a first project. Hence, I wouldn't worry about it; the joints in the second photo might not be brilliant but if you can do that type of soldering I am sure you can manage a 4-pin Lemo as well. It will certainly be more reliable than trying to do crimping using pair of pliers.

It might be worth practicing soldering on say a cheap DIN or D-sub connector before you attempt the Lemo.
 
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  • #27
I've come up with a natural solution that doesn't require me to solder the connector. There is this Eonvic FFG.0B to USB cable suggested to me earlier but I didn't get it because the keying is wrong (FGG instead of FGC and I don't want to saw the key to avoid wrong rotation). But after learning more about them and acquiring a set of used FGC shell that is obsolete now. I will just try to replace the shell of the Eonvic with that of the FGC. Does anyone know the pin configuration of the "PD Movie". What's a PD Movie? If the pins don't match. Then I have to cut the cable in half and rewire all the 4 wires, at the cost of lost of any shield (if there is).

https://www.amazon.com/gp/product/B06XKV73C1/?tag=pfamazon01-20

What other USB to 4 pin LEMO do you know besides it, which I can acquire and reconfigure?
 
  • #28
View attachment 1705035196876.webp

There are two possibilities for the condition of those solder connections.

1) The connector pins may have been dirty or oxidized. Any dirt, corrosion or oxidation Must be cleaned off of surfaces because it blocks the solder from getting to the metal.

2) The connector pins may not have been hot enough. To get a good solder joint the pieces themselves must be hot enough to melt the solder.

After the parts are clean, a good approach is:

PROCEDURE
Before you start. put a small amount of solder on the tip.

The solder iron the tip should have an even coating of solder. If the solder balls up into clumps or doesn't cover the tip, then the tip is dirty/oxidized. clean it by wiping on a wet sponge, (natural sponges work best, the common synthetic ones you buy in the grocery store tend to melt and leave a mess on the tip) add some solder and try again. This keeps the tip from oxidizing, instead the film of solder oxidizes.

When you are ready for the next joint, wipe the tip on a wet sponge (or some wet paper towels folded up).

Then put a little bit of solder on the tip.

1) have a little bit of fresh solder on the solder iron tip

2) put the solder iron on the largest part where you want the joint

3) feed the solder onto the part that you want to solder, not onto the iron.
when the part starts to melt the solder you can, if needed, move the iron around to get a good solder coating where the joint will be (this operation is called "tinning" but is not always needed on new, clean parts)​

4) assemble the wire to the joint

5) put the solder iron on the joint so it is in good contact with both parts of the joint

6) feed solder to the spot where the joint and solder iron meet
(it doesn't take a lot of solder, if the wire and joint area are covered enough that there is a fillet of solder where they meet they are good. for instance the Military spec for soldering states that you should be able to see the outline of the wire; most of us often use a little bit more)​

7) when enough solder flows, remove the solder and the iron
DO NOT MOVE THE CONNECTION UNTIL THE SOLDER SOLIDIFIES!

If the connection is disturbed before the solder solidifies, the solder will crystalize (look grainy and perhaps have a slightly gray color) and be very weak. This is called a "cold solder joint."

Then put a little bit of solder on the solder iron tip and set it down.Hope this helps!

Cheers,
Tom
 

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