DE-5000 LCR TL-21 mod.

[Corner]

That looks amazing

[jerolee]

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 $$$$$$!

[McBryce]

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.

[Fraser]

McBryce,

Would you consider sharing your 3D print files for the box please ?

Best Wishes

Fraser

[precaud]

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.

[McBryce]

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.

[Fraser]

Brilliant 

Thank you 

Fraser

[cdev]

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
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.

[Acecool]

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.

[TimFox]

What gauge wire are those GX-series connectors designed for?  I had trouble with them on another project.

[Acecool]

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.

[TimFox]

My problem was with the internal dimension of the solder cups--extremely small internal diameter.  I don't remember which suffix on the GX.

[sequoia]

I wanted to use Kelvin clips that I use with bench multimeters. So, I ended up adding banana jacks:

[Acecool]

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.

[mansaxel]

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.

[Corner]

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?

[sequoia]

@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?

[sequoia]

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....

[Acecool]

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.

[mansaxel]

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.

[McBryce]

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.

[donlisms]

I would have been interested in ESR and low resistance readings, where Kelvin connections can really do their thing...  Could you, would you?   

[Electro Fan]

- makes a pretty good case for the benefit of the guard connection
https://youtu.be/UTCKNm-PYWs

[jerolee]

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!
.

[coromonadalix]