EEVblog® Electronics Community Forum
Products => Test Equipment => Topic started by: McBryce on February 10, 2016, 04:20:23 am
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Hi all,
I got a DER EE DE-5000 (also sold as IET) LCR meter a while back. It came with a TL-21 connector that looks like this: http://www.japaninabox.jp/wp/wp-content/uploads/2013/08/der-ee-de-5000-high-accuracy-andheld-lcr-meter-with-tl21-tl22-tl23-iet-06.jpg (http://www.japaninabox.jp/wp/wp-content/uploads/2013/08/der-ee-de-5000-high-accuracy-andheld-lcr-meter-with-tl21-tl22-tl23-iet-06.jpg)
The problem is, the crocodile clips are crap. They're pretty cheap, don't grip the components pins particularly good and the wires are so short that they can be difficult to connect at all to some parts. My plan is to remove them and install 4 banana sockets so that I can use my standard Kelvin clips with it. Has anyone tried this yet? Is there enough space in the case for sockets? And is there any disadvantages to doing this? The meter is taking a 4-wire measurement, but the 4 wires actually connect at the base of the crocodile clip at the moment, so using proper Kelvin clips should actually give a more accurate reading.
McBryce.
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I modified mine. I purchased some cheap Kelvin clips on ebay, cut off the ends,and soldered the cables directly to the board in place of the cheap aligator clips.
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I was going to do the same thing with mine. I bought a spare tweezer set so that I could replace it if it breaks (again). I think the price was about the same.
I was planning on using Mueller kelvin clips that I had as spares. I already bought the Extech LCR205 smt adapter for it too, but the blades of the adapter aren't quite long enough for a secure fit.
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I'd prefer not to solder the Kelvin clips onto the TL-21 as I use them on other meters too. I'll have to investigate the smallest 4mm sockets I can get and see if I can fit four of them into the case.
McBryce.
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It is cheaper, easier, and better IMHO to just buy these and solder them in:
http://www.ebay.com/itm/LCR-Meter-Test-Leads-Clip-Kelvin-Wires-With-2-BNC-per-Channel-Red-Black-/171907327574?hash=item280679a656:g:eLIAAOxyhXRTO-7i (http://www.ebay.com/itm/LCR-Meter-Test-Leads-Clip-Kelvin-Wires-With-2-BNC-per-Channel-Red-Black-/171907327574?hash=item280679a656:g:eLIAAOxyhXRTO-7i)
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Yes, it's probably easier, but I doubt it's cheaper. It also means that the TL-21 then becomes a case with bulky leads (and I already have way too many leads around the room). With sockets it becomes a tidy little box and I just use the leads I already have. I've just ordered the smallest sockets I could find (for €5). I'll see if they fit when they get here.
McBryce.
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Yes, it's probably easier, but I doubt it's cheaper. It also means that the TL-21 then becomes a case with bulky leads (and I already have way too many leads around the room). With sockets it becomes a tidy little box and I just use the leads I already have. I've just ordered the smallest sockets I could find (for €5). I'll see if they fit when they get here.
McBryce.
Don't forget this is a 5-wire connection, not a 4-wire connection. If you break the kelvin leads out into their individual lines you are supposed to have a guard shield around the lines too. Even the short alligator leads use shielded cable (with all of the shields connected together to the guard pin). This supposedly becomes even more important at longer lengths.
You can see the shielding here (the braided copper) soldered to the guard-line:
(http://i.imgur.com/ix3Ms9x.jpg]http://i.imgur.com/ix3Ms9x.jpg)
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Here are mine made from an Ebay kelvin set with a BNC end.
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I bought two extra TL-21's to make fixtures.
On one, I replaced the two black cables with two teflon shielded twisted pair cables to Kelvin clips, roughly 60 cm long.
On the other, I replaced the black cables with four RG-174 coax cables to BNC plugs, to allow making "black box" fixtures with binding posts at different spacings.
In the black-box fixtures, I included a small switch to short the binding posts together for short-circuit calibration, using multiple-pole miniature toggles to reduce the contact resistance.
I kept the original TL-21: I haven't had any problems with the alligators except that the plastic covers make them stiff.
I'm looking for a good way to keep the alligators the correct distance apart (corresponding to the final spacing on the component) when doing the open-circuit calibration.
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what is the good kelvin clip?
(http://www.electronicecircuits.com/download/r/electronicecircuits.com%20kelvin%20clip%20s-l500.jpg)
OR
(http://www.electronicecircuits.com/download/r/electronicecircuits.com%20kelvin%20clip%20s-l1600.jpg)
one type has 2 wire connect to both kelvin clip end and other type 2 wire connect to one end.
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They are both connected the same. The cables in the second picture loop around to the other side of the clip near the hinge.
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Yes, it's probably easier, but I doubt it's cheaper. It also means that the TL-21 then becomes a case with bulky leads (and I already have way too many leads around the room). With sockets it becomes a tidy little box and I just use the leads I already have. I've just ordered the smallest sockets I could find (for €5). I'll see if they fit when they get here.
McBryce.
Don't forget this is a 5-wire connection, not a 4-wire connection. If you break the kelvin leads out into their individual lines you are supposed to have a guard shield around the lines too. Even the short alligator leads use shielded cable (with all of the shields connected together to the guard pin). This supposedly becomes even more important at longer lengths.
You can see the shielding here (the braided copper) soldered to the guard-line:
(http://i.imgur.com/ix3Ms9x.jpg]http://i.imgur.com/ix3Ms9x.jpg)
Yes, I was aware of the guard connection, but I intended leaving that unconnected as my Kelvin clips (like the mods shown above) don't contain an additional shield anyway. Lots of ideas to go on though now, thanks for all the ideas and pics. I'll post a picture of what I've done when it's finished.
McBryce.
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Another DE-5000 LCR mod. :popcorn:
http://designideas.cocolog-nifty.com/blog/2014/09/de-5000-test-fi.html (http://designideas.cocolog-nifty.com/blog/2014/09/de-5000-test-fi.html)
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A bit more than I actually need, but thanks for the link. Still waiting for the 4mm sockets to arrive before I start my mod.
McBryce.
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(http://designideas.cocolog-nifty.com/blog/images/2016/02/16/20160216_095619.jpg)
Waitaminute ... so there's a PCB with SMD pads in the TL21 that's covered with this sticker? Why didn't they leave it exposed?
I think I'll have to take a knife to mine ...
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So that it is what the circuit board is for! The problem is, as built, it stil can't do anything without soldering some wires to it. his would also render the external test connections less accurate as the circuit board would be adding its capacitance and inductance to the reading.
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:palm: You're right, one would probably want to remove the PCB to which the wires are attached, hook up the SMD PCB to the blade contacts and make a dedicated TL-21 for SMD devices.
On closer inspection, the SMD pads don't have a Kelvin connection either ... :-//
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...and make a dedicated TL-21 for SMD devices.
You mean like the TL-22 ?
McBryce.
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...and make a dedicated TL-21 for SMD devices.
You mean like the TL-22 ?
McBryce.
The tweezers aren't that great. I have them. The tips are not very precise (cheap stamped metal) and the thick cable is clumsy. Putting SMD components directly on a PCB would work better, IMHO. It's really odd that they would go to the lengths to manufacture those PCBs but then not hook them up and hide them under a sticker.
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Yes, I have a TL-22 myself. It does the job more or less, but it's galaxies away from winning any prizes for design or usability. The manufacturing quality is relatively good, it's just a bad design.
But back to the TL-21. I've opened mine and the PCB under the lid on mine is a non-etched PCB. So there seems to be different versions. See below.
The sockets arrived. They were the smallest 4mm shrouded sockets I could find, but there's not a chance I can get 4 of them on the case, so I'll have to come up with some other solution >:(
McBryce.
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The sockets arrived. They were the smallest 4mm shrouded sockets I could find, but there's not a chance I can get 4 of them on the case, so I'll have to come up with some other solution >:(
McBryce.
This is why I suggested buying another set of Kelvin leads and just soldering them directly. It is the surest and cheapest solution.
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I modified TL-21 adapter as well, see my post broken-der-de-5000-tl-21-crocodile-clip-adapter (https://www.eevblog.com/forum/repair/broken-der-de-5000-tl-21-crocodile-clip-adapter/)
TL-21 has tendency to break internal solder joints - I had to repair it.
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Also please have a look here:
https://www.eevblog.com/forum/testgear/der-ee-de-5000-lcr-meter-with-changeable-cables/ (https://www.eevblog.com/forum/testgear/der-ee-de-5000-lcr-meter-with-changeable-cables/)
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Yes, it's probably easier, but I doubt it's cheaper. It also means that the TL-21 then becomes a case with bulky leads (and I already have way too many leads around the room). With sockets it becomes a tidy little box and I just use the leads I already have. I've just ordered the smallest sockets I could find (for €5). I'll see if they fit when they get here.
McBryce.
Don't forget this is a 5-wire connection, not a 4-wire connection. If you break the kelvin leads out into their individual lines you are supposed to have a guard shield around the lines too. Even the short alligator leads use shielded cable (with all of the shields connected together to the guard pin). This supposedly becomes even more important at longer lengths.
You can see the shielding here (the braided copper) soldered to the guard-line:
(http://i.imgur.com/ix3Ms9x.jpg]http://i.imgur.com/ix3Ms9x.jpg)
Yes, I was aware of the guard connection, but I intended leaving that unconnected as my Kelvin clips (like the mods shown above) don't contain an additional shield anyway. Lots of ideas to go on though now, thanks for all the ideas and pics. I'll post a picture of what I've done when it's finished.
McBryce.
Hi McBryce, did you manage to get yours to work perfectly? I have these leads I hand made a while ago. Each wire is just 14AWG stranded wire. I cut the plug ends off only to realise I also need a guard wire to connect onto the TL21... I should have checked these threads first before I sacrificed a pair of leads.
I assume that I can't easily mod my existing leads to have a guard wire. Can I safely leave the guard wire out and only connect 4 wires to TL21? Would this affect measurements, say for small resistors and capacitors?
Edit: Attach photo
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Hi Corner,
in the end I used shielded Kelvin clips with 4x BNC connectors. I 3D printed a new housing to put it all into. This is what it looks like. The measurements with this are identical to the values I get with the original short clips.
McBryce.
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That looks amazing
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Awesome piece of work, i like it.
I would be interested in such a box. im struggeling with the same issue. My readings are not stable, i gues its the cheap pcb connector strips plugged into the device. Component legs straight into the clips give me better readings.
Im in to get a more decent bench LCR meter anyway but $$$$$$!
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The PCB I used was a blank two sided PCB. It needs to be the thinner 1mm stuff, the standard 1.5mm PCB won't fit between the blades. I didn't bother etching it, I just used a hacksaw to seperate the three/six contacts.
As for the meter, I'm pretty happy with it, not looking to upgrade any time soon.
McBryce.
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McBryce,
Would you consider sharing your 3D print files for the box please ?
Best Wishes
Fraser
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what is the good kelvin clip?
Whichever one you get, check the connections to the BNC adapters and make sure they are soldered properly. Makes a big difference when measuring low-impedance parts.
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McBryce,
Would you consider sharing your 3D print files for the box please ?
Best Wishes
Fraser
I think the lid file may be upside down (needs to be flipped 180 before printing). There are two versions here, one with the BNC holes and the other is blank for designing your own variation.
McBryce.
EDIT: I just discovered that mistakes crept into this version when I made minor tweaks. I will upload a new version later in this thread.
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Brilliant :-+
Thank you :)
Fraser
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As far as grip, they grip very strongly, and after having tried to find smaller, stronger clips for a very similar purpose, and also recently having gotten a TINY network analyzer, and given that the issue, though important to me doesn't start to get critical except at much higher frequencies, I decided to devote that same energy to developing better text fixtures to use on my nanovna. You'll be able to get the same data, but better and going much higher.
People who have done the conversion, how different are your readings?
Hi all,
I got a DER EE DE-5000 (also sold as IET) LCR meter a while back. It came with a TL-21 connector that looks like this: http://www.japaninabox.jp/wp/wp-content/uploads/2013/08/der-ee-de-5000-high-accuracy-andheld-lcr-meter-with-tl21-tl22-tl23-iet-06.jpg (http://www.japaninabox.jp/wp/wp-content/uploads/2013/08/der-ee-de-5000-high-accuracy-andheld-lcr-meter-with-tl21-tl22-tl23-iet-06.jpg)
The problem is, the crocodile clips are crap. They're pretty cheap, don't grip the components pins particularly good and the wires are so short that they can be difficult to connect at all to some parts. My plan is to remove them and install 4 banana sockets so that I can use my standard Kelvin clips with it. Has anyone tried this yet? Is there enough space in the case for sockets? And is there any disadvantages to doing this? The meter is taking a 4-wire measurement, but the 4 wires actually connect at the base of the crocodile clip at the moment, so using proper Kelvin clips should actually give a more accurate reading.
McBryce.
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I modified a box of mine.. I was thinking of using BNC connectors in the actual unit but I didn't like having to plug 4 things in.. additionally, because of the box it wouldn't fit into the slot. So I originally had 2 shielded BNC 6" leads, 4 of them... I had red and black heat shrink tubing to denote ground or one section and the other section...
This worked well, but I hated the 4 connections and I didn't like the leads hanging out. It made it difficult with how much stuff was in the box. So I used GX16 connector, the Chinese airplane connector with screw cap... Ground is soldered directly to the threads to ensure ground goes through and to the shielding... It passes the calibration and works. I have 2 of the ebay alligator BNC wires ( $20 USD each or so ).. One I left with BNC, one has the GX16 connector on it.
It works, and I can keep the connection permanent but typically I have to remove it to put it in the box. There is less stuff to worry about int he box now that I have a single box - the tweezers were also modified to the GX16 connector and I have yet to do the small alligators as I'll probably keep that as a control module. I do have a spare set of tweezers too and another box I have disasembled.
Someone suggested I use audio XLR connectors - mini or normal. They are much higher quality, gold plated in some cases. I priced out the connectors as they are pricey but they don't screw on and have a designated ground pin. I would probably have a 1 inch lead coming out of the box too so it'll fit in the stock storage box as one issue I do have with the GX connector is that if I put the box in the unit first, then plug tweezers or the alligator clips in... I can't screw it in. I have to unplug it just a bit then I can push it in but it puts it at a slight slant. I don't want to modify the unit to let that fit as I'll probably screw it up and make it look bad, like I did with the box which I'll probably fix using spin welding.
Look for my posts, I have some photos, etc.. I think.
The GX16-4 connector ( the 4 pins are for each normal pin, and ground goes through the threads, then the shielding of the cable ) is the one I'm using.. I will probably switch to the higher quality XLR connectors because there is a built in ground tab to solder to, and the connectors come apart and go together much better. Plus the gold plating, etc... It'll cost quite a bit, but it will also make it much easier to just plug something in and use it, then I can plug something else in and go with it too.
Right now being able to plug in a single plug and have access to alligator clips on decently long leads is nice, plus the tweezers, etc... I can just plug in and use - no need to screw it in unless I want the ground but most don't use it... although it is probably a good thing to have the ground running through the shielding. Or, maybe it'll create a capacitor effect as power does run through the + wires.
Edit:
Also, when I go for the XLR connectors - instead of just having the ground running through the shield... I'm thinking of having the ground run through the shield, in addition having 1 pin as a ground too. so the 5 pin connector. Still debating on this. The point of this would be so if the ground tab has an issue, with the ground going straight to another pin, on each connector I can create a jumper to go from the pin I choose for ground, and the ground tab and the shielding. This way if there is ever an issue, or it ends up fitting loosely at some point in the future... the ground will be a solid connection regardless. This is probably overkill, and I won't be using 5 core wire... it will still be ground through the shielding, but to have the ground go through a pin as well as the connector would just ensure that connection.
What do you all think of that idea? Should I just go with the 4 pin with ground through the outside, or go with the 5 pin and the jumper? I'm leaning towards 5 pin just because it wouldn't be difficult to do and would make sure the ground is never in question. I've never worked with the XLR connectors so I'm not sure how well the outside connection fits - I'm assuming it is decent enough but while it can clip together, the connections have some black layer on the outside so I don't know if it is conductive or not. It could be, but it could also be a protective coating. The inside should be fine if the outside has a protective coating. But I'd rather be 100% especially as I haven't worked with them before - another reason for the 5 pin.
I am also planning on getting 1 or 2 main female connectors, and the rest male - 5 or so so I can create up to 5 connections. 2 are spoken for, and I may make a small alligator clip set too just to have it in the box especially as with needing only 1 box it would mean a lot more room in the carry box. I may make a second one just so I could swap between them - but I highly doubt the machine has any way to tell, unless in software, what is connected and how it was calibrated. If it can, then 2 boxes wouldn't be a bad idea to quickly switch from one thing to another... but unplugging something and plugging the other in could be just as effective if I don't need to calibrate... but I probably do.
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What gauge wire are those GX-series connectors designed for? I had trouble with them on another project.
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The tabs are pretty large on the inside but I typically heat shrink them just so they don't hit the outer shell. You could probably get a solid coax wire on them....
They are used in soldering stations, heat gun / rework stations, and more... so they can handle a lot of current and they've never gotten hot on me despite pushing an iron and heat gun to its absolute highest temps and highest fan speed setting. So very little resistance - but then again it is a bigger piece of metal and the metal box of the station acts as a heatsink which could be why the wire may be warmer...
You can get smaller GX connectors. GX16 is 16mm, GX12 is 12mm, which is the mini ones ( these screw in - the 16mm pushes in, then has a small turn, then a locking / set screw is used to stop it from coming undone. The 12mm - typically photos online show the GX16 instead of the 12... it has no set screw and just screws in - this does work well... )
My T12 station uses the GX12 connector. It is tighter in there but it could probably fit close to the same wire inside, especially with heat wrap as the divider may be smaller... I'll take it apart to verify this - but as for the exact spec of what you can use - not sure. I wouldn't go larger than the actual pins inside the connector and those measurements are...
GX16 5 pin: 1.9mm - These typically have 12 to 24v going through at or around 4 to 5 amps at 100% power to the T12 soldering station - or this is what the station itself is drawing from the wall - I'd have to double check... I saw these numbers from a video review of the KSGER T12 station... it should be 24V 4 + amps. not sure how much is making it to the tip. but that is typically in short bursts.
GX16 8 pin: 1.25mm - This is used for the heat-gun and these typically have 110v going to the heating element - unsure on amps
GX12: 1.2mm
That being said, a lot of Chinese manufacturers typically under-engineer the design so these may be absolute highs for these connectors... however I've never noticed any melting, arcing, etc.. but I go through and do some extra work on them to be absolutely sure there won't be an issue by adding heat shrink, redoing the joints, etc...
Also, the connectors likely have a lot of flaws in them so it is quite possible that there is a lot of resistance within them... they are inexpensive and not always the best quality - hence one reason I want to switch to something better made.
I'd be spending around $30 in connectors for the XLR-5 connectors... normal or mini.
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My problem was with the internal dimension of the solder cups--extremely small internal diameter. I don't remember which suffix on the GX.
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I wanted to use Kelvin clips that I use with bench multimeters. So, I ended up adding banana jacks:
[attachimg=1]
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They can be quite tricky to solder and get to.. it is best to pre-tin everything and blob up the connectors. There is a cradle and there is a hole. Don't use the hole - just cradle the wire and that's it.
I had an issue with mine too once where it felt almost like it was difficult to solder to the pieces and get everything squeezed into the connector. I don't recall why this was the case. I know it can sometimes be odd to get it packed in, and make the slight turn required on the GX16 ( if you measure the connector around the female plug at the widest point - the rim which is held on by the retained nut, without measuring the nut - that should give that value clamped to the nearest mm... )
I have to redo my hot air gun so I'll put it on video.'
@sequoia
The banana jacks actually look decent. I had around the same length of 4x BNC connectors and I didn't like all the mass... the banana jacks are nice but it doesn't give the option to pass on any shielding to the tool if it has that option, or pass it on to an extension is the only downside I see to it.
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Also, the connectors likely have a lot of flaws in them so it is quite possible that there is a lot of resistance within them... they are inexpensive and not always the best quality - hence one reason I want to switch to something better made.
I'd be spending around $30 in connectors for the XLR-5 connectors... normal or mini.
My 5€-Cents:
A Neutrik XLR is probably not going to wear out on you. I'd get the silver plated ones if I did it, because they hold up better to mating cycles than the gold ones. Mouser has NC5FXX (female cable) for ~ €6, and mating male chassis connector NC5MP for around €7. I chose this combination of male / female because the male chassis is narrower (it's the old Cannon / Switchcraft standard for a 19mm hole with two 3mm holes top and bottom for screws) and should fit better on the TL style box. The Guard connection IMNSHO should get a separate pin, and also be connected to the shell via the dedicated tab. From pure habit, I'd do the following pin-out:
- Guard
- Positive clamp drive
- Positive clamp sense
- Negative clamp drive
- Negative clamp sense
(Does the terminology make sense?)
This way you can extend with COTS DMX512 cable if you wish.
If you want something smaller, I'd research two things;
- Screw-lock DIN connectors as made by Binder. They've been used for microphone connection when the RFI qualities of XLR aren't up to spec.
- Automation machinery M series connectors. Smaller than the Binder. TE makes an extensive range. I think you'd be best off with a M12 style housing.
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I wanted to use Kelvin clips that I use with bench multimeters. So, I ended up adding banana jacks:
(Attachment Link)
It's hard to see but I assume those are 14 AWG wires from the looks. How did you manage to cram them all in that little hole? Did you make the hole bigger?
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@sequoia
The banana jacks actually look decent. I had around the same length of 4x BNC connectors and I didn't like all the mass... the banana jacks are nice but it doesn't give the option to pass on any shielding to the tool if it has that option, or pass it on to an extension is the only downside I see to it.
My Kelvin clips set doesn't have a guard/shielding connection. But presumably if one has Kelvin clip set with banana plugs, it would also have banana plug for the guard/shield (?). Then should be able to plug in directly to TL-21 guard socket? (or may need to make banana plug to banana jack adapter cable if have safety banana plug...).
Btw, is there any bench multimeters (with 4-Wire measurement terminals) that also have connection for guard/shielding?
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It's hard to see but I assume those are 14 AWG wires from the looks. How did you manage to cram them all in that little hole? Did you make the hole bigger?
Yes, I had to modify the plastic case little bit, to enlarge the opening enough to fit through 4 of those 14 AWG silicone cables. Could have used thinner cable, but then it would not have fit nicely to those "safety" banana jacks....
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Yeah, I'm leaning towards 5 pin - basically if the end tool being plugged in has a ground then it can be used from the pin instead of the ground tab with xlr... and if an extension is used then it can go through shielding, ground pin and also the pin itself.
I'll see where I posted my images in a bit to show mine - I did make the hole bigger when it was the 4 shielded BNC cables... with the GX connector, I had to make it much bigger and I cut the PCB just so the threads don't cut into it. I also soldered the ground wire directly to the threads - required lots of heat and time with my old iron..
The XLR plugs just seem much higher quality...
And I am leaning towards the gold, but it should be nickel underneath but I'll double check. I was setting up 2 orders - one mini, one large. One of the component sites had them for less money than on eBay too.. Still expensive... I will double check regarding the nickel only. Although, if I do use the hold plated - gold on gold should last a very long time since I'll be modifying the tools / attachments to use the new connectors. Right now using GX16... - also I got the measurement section wrong... it is 16mm but I can't recall where you measure.
Also, I was going to do this for the GX connector, but I've decided to wait until I get the XLR plugs - make more attachments... ie: GX to BNC breakout... GX to Banana, and so on... Now XLR to XXX --- the good thing about going to Banana or BNC, or whatever... I could always have the ground Banana come with... ie: the guard plug. So if you use an adapter to go from XLR to Banana, then you end up with 5 plugs. To BNC you end up with 2 BNC plus one banana... And all of these will be small so they'll all fit in the carry box.
As far as soldering the GX connectors - not a fan. I just redid my heat gun because I wasn't happy. Added a heat-shrink tube with glue as strain relief - and it is super stiff now right there, aand works as intended... but the wires were super short... it had to be because there is no space to put it in.. .this is what I don't like about the GX connectors... the mini GX are better than the large, but still annoying. The XLR connectors seem a lot better as they are longer. I also did redid the pin-out for the heatgun so the white wire for the heat gun ( because the thick white wire is in the center, and I used the wire default wire positions as the new pin out )... so no need to cross wires. I also alternated heat shrink - so the center pin has heat shrink ( ie pin 8, 1 / 7, and 3 / 5 all have heat shrink with 2, 4 and 6 without )... then a large heat shrink to add a barrier between the pins and the wall of the connector.
It looks so good right now... I wouldn't want to do it again though... not a fan of the GX normal size connectors.... I'll be placing the order for the XLR soon.
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Also, I was going to do this for the GX connector, but I've decided to wait until I get the XLR plugs - make more attachments... ie: GX to BNC breakout... GX to Banana, and so on... Now XLR to XXX --- the good thing about going to Banana or BNC, or whatever... I could always have the ground Banana come with... ie: the guard plug. So if you use an adapter to go from XLR to Banana, then you end up with 5 plugs. To BNC you end up with 2 BNC plus one banana... And all of these will be small so they'll all fit in the carry box.
Hmm, shouldn't that be "To BNC you end up with 4 BNC"? I'm thinking the Guard connection should be shield on all connectors, whether driver or sense. They're all sensitive, and borderline RF if measuring @ 100KHz. There are no problems doing another Guard banana in parallel, of course. But its efficiency as a RF shunt goes down with length.
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As far as grip, they grip very strongly, and after having tried to find smaller, stronger clips for a very similar purpose, and also recently having gotten a TINY network analyzer, and given that the issue, though important to me doesn't start to get critical except at much higher frequencies, I decided to devote that same energy to developing better text fixtures to use on my nanovna. You'll be able to get the same data, but better and going much higher.
People who have done the conversion, how different are your readings?
I did a few quick comparisons last night:
Sample Capacitors: 33pf Ceramic, 47nf Multilayer Ceramic, 470µf (cheap crap) Electrolytic
Results:
Plugged directly into slots on meter = 33.3pf - 48.50nf - 394µf
Original unmodded TL-21 = 33.7pf - 47.75nf - 394µf
My mod - 4x BNC / shielded Kelvin clips = 33.4pf - 48.38nf - 394µf
So all results are very similar, just with my BNC solution, I can leave the LCR meter on the shelf and have half a metre of cable to the component.
The meter was of course recalibrated each time I swapped the leads.
McBryce.
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I would have been interested in ESR and low resistance readings, where Kelvin connections can really do their thing... Could you, would you? :)
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- makes a pretty good case for the benefit of the guard connection
https://youtu.be/UTCKNm-PYWs
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McBryce was so friendly to print a box for my meter. It works a treat! The small alligator clips didnt pass the Cal half the time and readings were odd the least to say.
Now with the 4 lead extensions, the readings are fine. awesome mod.
Thanks McBryce!
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:-+
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Hi! I am modding my TL-21, and ran into some issues. I've tried attaching kelvin clips with short (15cm) and thick (16AWG) wires directly to the little PCB inside the TL-21.
Nothing is shielded. The system calibrates OK, but touching the wires or clips while measuring adds from 5 to 10 pF to the measurement.
Does shielding solve this problem? Also, does the shield need to be grounded to work, or does it provide a benefit even without grounding?
In other words, should I replace the thick unshielded wires with thinner, but shielded wires?
Thank you!
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In case anybody reads this seemingly dead thread, here are a few of my notes on the project.
1. Unshielded cables are not an option. Touching the insulated cable with a hand is enough to throw off the measurement.
2. Shielding works well enough even without grounding.
3. Clean your flux after soldering! The device is sensitive enough to pick up the 20 MOhm path between terminals across the flux residue on the board.
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Hey, does the DE 5000 comes with a backlight ? I don't remember the one I used to have one !
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Yes, it has a weak blue backlight.
For those wanting to print the case seen above, here's the final model files.
McBryce.
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This my solution.
For about 3€ I orderded an assembly with 4 BNC connectors
https://nl.aliexpress.com/item/32821941000.html?spm=a2g0s.9042311.0.0.27424c4dOL721x
to connect the 7€ Kelvin lead
https://nl.aliexpress.com/item/32505106470.html?spm=a2g0s.9042311.0.0.27424c4dtt72tJ
Used a piece two layer pcb board for the fingers. With a small drill I made the correct layout for the connections and attached the BNC connectors to the pcb board.
The pictures show the result
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The Voltlog guy has a board available on Tindie that MAY work in the DE-5000 and has some big pads to attach the wires. I have a couple on the way to try out.
https://www.tindie.com/products/voltlog/lcr-meter-kelvin-test-lead-adapter-pcb/ (https://www.tindie.com/products/voltlog/lcr-meter-kelvin-test-lead-adapter-pcb/)
(https://cdn.tindiemedia.com/images/resize/moNqArtTtTCUk5mkkvAdVYYHSig=/p/full-fit-in/2400x1600/i/410352/products/2021-01-04T11%3A18%3A24.614Z-IMG_8942.JPG?1609730336)
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The Voltlog guy has a board available on Tindie that MAY work in the DE-5000 and has some big pads to attach the wires. I have a couple on the way to try out.
https://www.tindie.com/products/voltlog/lcr-meter-kelvin-test-lead-adapter-pcb/ (https://www.tindie.com/products/voltlog/lcr-meter-kelvin-test-lead-adapter-pcb/)
(https://cdn.tindiemedia.com/images/resize/moNqArtTtTCUk5mkkvAdVYYHSig=/p/full-fit-in/2400x1600/i/410352/products/2021-01-04T11%3A18%3A24.614Z-IMG_8942.JPG?1609730336)
They look like 1.6mm boards. They'll be extremely difficult to insert, the original boards are 0.5mm.
McBryce.
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Originals are actually 1mm not 0.5, but I agree, 1.6 is gonna be tight. Best to just order your own from the usual cheapo-pcb suspects.
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Originals are actually 1mm not 0.5, but I agree, 1.6 is gonna be tight. Best to just order your own from the usual cheapo-pcb suspects.
Doh, yeah. Posted before my first coffee.
McBryce.
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Thanks for noticing that. I will not be trying to force them into the DE-5000 now, that's for sure. I was actually thinking the spacing of the tabs might be different, not the thickness.
If anyone does happen to OSH out a board let us know :).
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The "layout" is so simple, I just "etched" the separators on a blank double-sided PCB with a hacksaw.
McBryce.
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Finally, I had time to build my modified version of the Kelvin Clip adapter for DE-5000. Thanks, McBryce for sharing his adapter from which I have been inspired very much.
My primary goals for the modifications were:
- To be able to use the adapter both on horizontal and angled vertical positions. Because of the length of the BNC connectors of the cable I had to shift the female connectors on the adapter a little bit upper and in a slightly angled position.
- To use less wiring inside the adapter I designed the PCB layout compatible with the current positions of the inner pins of female BNC connectors. Soldering a small length (3-4mm) of wire between the pin and PCB was enough.
- Having a pair of discharging pads on the top. (through a 1K resistor)
Used the following connectors and a double-sided PCB with 0.8 mm thickness.
L-KLS1-BNC015 (https://cdn.ozdisan.com/ETicaret_Dosya/700408_151862.pdf)
https://www.aliexpress.com/item/32472482265.html (https://www.aliexpress.com/item/32472482265.html)
Here are the pics:
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Finally, I had time to build my modified version of the Kelvin Clip adapter for DE-5000. Thanks, Mr. Bryce, for sharing his adapter from which I have been inspired very much.
My primary goals for the modifications were:
- To be able to use the adapter both on horizontal and angled vertical positions. Because of the length of the BNC connectors of the cable I had to shift the female connectors on the adapter a little bit upper and in a slightly angled position.
- To use less wiring inside the adapter I designed the PCB layout compatible with the current positions of the inner pins of female BNC connectors. Soldering a small length (3-4mm) of wire between the pin and PCB was enough.
- Having a pair of discharging pads on the top. (through a 1K resistor)
Used the following connectors and a double-sided PCB with 0.8 mm thickness.
L-KLS1-BNC015 (https://cdn.ozdisan.com/ETicaret_Dosya/700408_151862.pdf)
https://www.aliexpress.com/item/32472482265.html (https://www.aliexpress.com/item/32472482265.html)
Very cool improvements!
McBryce.
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So far, I am happy with the results. As posted before, cleaning the flux residues and keeping the separating gaps as larger as possible is important.
I am planning to decrease the cable length of the clips for better stability. 50 cm is more than enough for my use.
STL files are uploaded to:
https://www.thingiverse.com/thing:5909801 (https://www.thingiverse.com/thing:5909801)
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Finally, I had time to build my modified version of the Kelvin Clip adapter for DE-5000. Thanks, McBryce for sharing his adapter from which I have been inspired very much.
My primary goals for the modifications were:
- To be able to use the adapter both on horizontal and angled vertical positions. Because of the length of the BNC connectors of the cable I had to shift the female connectors on the adapter a little bit upper and in a slightly angled position.
- To use less wiring inside the adapter I designed the PCB layout compatible with the current positions of the inner pins of female BNC connectors. Soldering a small length (3-4mm) of wire between the pin and PCB was enough.
- Having a pair of discharging pads on the top. (through a 1K resistor)
Used the following connectors and a double-sided PCB with 0.8 mm thickness.
L-KLS1-BNC015 (https://cdn.ozdisan.com/ETicaret_Dosya/700408_151862.pdf)
https://www.aliexpress.com/item/32472482265.html (https://www.aliexpress.com/item/32472482265.html)
Here are the pics:
Nice work, like the 3D printed mounting fixture for the BNCs :-+
Our solution wasn't as nice but simple. Basically get another TL-21 and replace the TL-21 cables with 4 short coaxial cables with BNC connectors to mate with the various LCR fixtures we utilize.
We found that with SMD fixtures the DE-5000 performs admirably as compared to our lab bench LCR meters, TH2830 and IM3536.
Best
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I realize this thread has been dormant for awhile but it looked like a good place to get some guidance. Thx
I'm finally getting around to adding some longer cables to the DE-5000. I bought some shielded cables with Kelvin clips and BNC connectors (that I have removed), and now I'm trying to figure out the connection points to the PCB.
I saw a post from IliyaOsnovikov on Defpom's youtube channel that said "Contacts "-2" and "+2" provide test signal and the other two "-1" and "+1" are sensing voltage." My particular Kelvin clips have the cables connected through just one handle side, so presumably the wire is slightly longer to the the opposite side. The post I saw went on to say "I wanted to keep a voltage sensing wire inside a shield as far as possible, right to an alligator clip contact. But the other wire supplying test signal can be run from one side of an alligator clip to another without shielding."
Maybe not a big deal either way, but thought I'd double check to confirm Iliya's wiring approach... ?
Thanks
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I am planning on shielding both sides, but shielding the driven signal might not matter. That project is sitting on my workbench again.
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What about just splicing kelvin clips to the existing wires rather than soldering them to the board? Is that less than optimal?
With no post office here since last January and 40 bucks a pop for the DER box, I'm reluctant to take the chance to screw something up.
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Here is a very simple and effective mod using an off-the-shelf product. You can buy ZB-L100K on several well-known sites both in the USA and in China. The price is low ($20-27) and the quality is quite decent. All four Kelvin clip wires are separately shielded. You may need to file the TL-21 cable entry point, as the ZB cable diameter is a bit too large.
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No need to modify the meter. Just bevel the ends of the blades on the adapter so they can open up the contacts in the meter. Also, the adapter installs upside down, i.e. cable on the left, to match the guard, hi, lo.
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I modified the original PCB here https://www.tindie.com/products/voltlog/lcr-meter-kelvin-test-lead-adapter-pcb-set-of-2/ (https://www.tindie.com/products/voltlog/lcr-meter-kelvin-test-lead-adapter-pcb-set-of-2/) to fit DER DE-5000
[attach=2]
See attached gerbers.
[attachimg=1]
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Hi Guys,
I bought a few extra TL-21 boxes but when I looked for them during my vacation (which is sadly over already) I couldn't find anything.
Does anybody know of a source inside the EU for these? Our Post is basically rejecting anything that comes from outside the EU for the last years, it doesn't even go to Customs and just gets sent back. We have no hope to buy anything from ebay and I don't use scamazon.
Thanks.
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some rg316...unravel the braid, cut maybe 50% of it away before you twist into a wire
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no idea why I went for the slightly further away ground point on the - side...oh well...probably wouldn't matter...I also forgot to put heatshrink around all four at the entry point, but I just cut off a piece of adhesive heatshrink and wrapped it around (as you can see in final photo)
anyway might be useful for some
(note all the cables are the exact same length in mine (well 1+ is a few mil shorter to line up)...but they end up as different lengths by time they make it out..add about 8-10mm to the - side if you want them to end up the same)
(make sure you tie the cable tie off the side as in pic...if it's up top it won't close)
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finished
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Nice work!!
See our earlier post (#64) where we utilized a low capacitance cable instead of RG316 to possibly reduce the variation in cable capacitance change with bending and orintation.
We developed a holder for the cables & connectors so they align with the standard LCR meter fixtures. Here's a few images.
Best
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A word of caution wrt a free floating female BNC on the end of a cable like with these adapter cables/fixtures for the DE-5000. When attaching to the male counterpart sometimes the electrical pin and socket within the BNC can rotate if both connection ends can spin. Having the female end secured can prevent this and improve connection wear and tear.
Best
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i ould have used "coax wires to bnc male" instead of passing thru another box, at some point you add many connexions losses ... my 2 cents
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The DE-5000 adapter we mentioned just above allows the use of a highly repeatable Open and Short calibration fixtures. Here's some images and also some measurements on some mica capacitors in our Direct Connect LCR Meter fixtures. These results are in excellent agreement with our lab grade bench LCR meters (TH2830 and IM3536), with speaks highly of the DE-5000 (why we have one!!!).
Best
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i ould have used "coax wires to bnc male" instead of passing thru another box, at some point you add many connexions losses ... my 2 cents
That will certainly work and how we started out, but still have 4 clumsy coax cables that need 4 BNC barrels to be properly terminated into the fixture (the LCR meter is female, all standard LCR fixtures have male BNCs). For best results these need to be in proper order and can't be haphazardly connected.
We decided to eliminate the 4 barrels and used what direct solderable female BNCs we had available at the time and also wanted to use the low capacitance cables. Still not satisfied with the 4 clumsy cables we decided to use the box approach where each BNC is properly spaced and fixed in position. This doesn't add any additional connections and makes setup much easier and repeatable, cables moving around doesn't work as well, we know, been-there-done-that ;)
Also this allows the use of the highly repeatable Open and Short as shown, and has shown excellent agreement with our reference mica capacitors as shown.
Anyway, we absolutely prefer this method over anything else we've tried. Of course YMMV :-+
BTW this fixture general concept was started back in #24 by McBryce.
Best
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Yes I think mawyat's solution above is best...all the issues he mentioned in the last few posts are relevant...that said I just wanted something easy and I don't have 3d printer...it seems to work fine if a bit fiddly.
also I checked the capacitance on the leads that come with some of these cheap aliexpress LCR bnc lead sets and it was much worse than rg316...i don't have anything flexy lying around that would be better...Mogami 2895 looks like it might be a good option though (expensive)...or rg179.
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the TH26011CS just arrived today...I seem to be getting good results...cal went fine...and if I move the cables about at 100 kHz readings are staying stable (to +/- 0.25 pf ish)...
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same cap direct inserted...with a recalibration first...
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Yes I think mawyat's solution above is best...all the issues he mentioned in the last few posts are relevant...that said I just wanted something easy and I don't have 3d printer...it seems to work fine if a bit fiddly.
also I checked the capacitance on the leads that come with some of these cheap aliexpress LCR bnc lead sets and it was much worse than rg316...i don't have anything flexy lying around that would be better...Mogami 2895 looks like it might be a good option though (expensive)...or rg179.
Well, now you have a yearning, reason, need, excuse, requirement for a 3D printer ;)
BTW with the fixture we mentioned, the DE-5000 has shown excellent agreement with our lab bench LCR meters over a wide range of components.
Having the same Open and Short Calibration Fixtures that work with different style LCR meters is a big benefit. Not to mention having the Reference Devices for comparisons within the same type Direct Connect fixture so the mechanical and electrical environments are identical between various meter types proves highly beneficial in reducing/eliminating variations and connection uncertainties. This shows in highly repeatable measurements and agreements with various instruments.
Best
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small piece of 20awg direct inserted vs. using leads...
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lol...actually I was thinking I could possibly use a 1590 box...I might try that some day if the loose cables start to annoy me...and use more appropriate cable etc.
Well, now you have a yearning, reason, need, excuse, requirement for a 3D printer ;)
I'm pretty happy with this setup now, think it's well enough accurate for me. But thanks for the replies mawyat...cool stuff! Cheers.
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Just for fun we grabbed the DE-5000 inserted the adapter and didn't even bother with an Open Short Cal since last it used the adapter fixture for this and we know this doesn't change from previous use (know this isn't advised but we are in a hurry).
No warm up, just grabbed each reference cap, inserted in DE-5000 fixture and recorded results.
Here's the results, red was just done with DE-5000 (in a hurry and took just a few minutes). Seems to be in good agreement with previous IM3536 LCR Meter readings.
Best
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Hi mawyatt, actually slightly OT question, I noticed if the gaps between these wires change (TH26011CS) it can throw off measurements a bit...quick fix I tied them up with some string for now...should I desolder and twist them tightly, or is parallel better?
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These are coaxial cables for each Force and Sense in the High and Low side LCR meter inputs. The center wire is the "active" wire while the shield becomes the BNC case, which for the DE-5000 is ground inside the TL-21.
The coaxial shields are single and not 100% shielding, so external/internal fields leak in/out, and the cable dielectric physical cross section gets changed slightly when bent, so the cable capacitance slightly changes. These contribute to the cable position, orientation & environment sensitivity, especially with low cap measurements. These are things we've known and dealt with since grad school well over 1/2 century ago when working with early Network Analyzer type measurements.
Tonghui makes some of the better LCR meters, cables and fixtures, so what you are seeing is better than some of the cheap type Kelvin clips (alto some can be pretty good, however some are not so and have really thin stingy shielding to help with flexibility, you don't know this until your measurements suffer). You can get Kelvin clips that go directly to the LCR meter with BNCs, or ones that have an extension box. This is likely because the extension box type Kelvin Clips (like you have) reduces the Kelvin cable length to the DUT before it gets combined within a much thicker and stiff cable with additional shielding going to the LCR meter. This allows finer more flexible cables to the Kelvin clips from the expansion box.
One of things we've mentioned and recommended from Hioki is to use a shielding plate below the measurements with Kelvin Clips. Connect this conducting shield plate to the Guard on the LCR meter. The works by controlling the localized fields around the DUT and Kelvin clips, improving measurement repeatability.
Another useful note is to make the Kelvin Clip Open calibration with the Kelvin Clips and cables in a similar fashion to the subsequent DUT measurement. While on LCR measurement notes, Zero Calibration with Kelvin Clips is best done with the Kelvin Clip in a Hc-Lc-Hp-Lp fashion, these notes help with High Z and Low Z DUT measurements respectively. You can find more details on both discussed here on EEVblog.
BTW are you contemplating a lab grade bench LCR meter?
Anyway, all this becomes a trade off between each of use and performance.
Best