Author Topic: DE-5000 LCR TL-21 mod. (Read 23963 times)

beowulfenator · « **Reply #50 on:** October 17, 2020, 10:25:28 pm »

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!

beowulfenator · « **Reply #51 on:** October 19, 2020, 07:28:02 pm »

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.

uski · « **Reply #52 on:** October 20, 2020, 04:40:49 am »

Hey, does the DE 5000 comes with a backlight ? I don't remember the one I used to have one !

McBryce · « **Reply #53 on:** October 20, 2020, 07:51:42 am »

Yes, it has a weak blue backlight.

For those wanting to print the case seen above, here's the final model files.

McBryce.

pdewestvries · « **Reply #54 on:** January 14, 2021, 02:45:00 pm »

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

BroMarduk · « **Reply #55 on:** January 26, 2021, 06:22:34 pm »

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/

McBryce · « **Reply #56 on:** January 27, 2021, 08:04:27 am »

Quote from: BroMarduk on January 26, 2021, 06:22:34 pm

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/

They look like 1.6mm boards. They'll be extremely difficult to insert, the original boards are 0.5mm.

McBryce.

Hydron · « **Reply #57 on:** January 27, 2021, 09:55:48 am »

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.

McBryce · « **Reply #58 on:** January 27, 2021, 10:14:10 am »

Quote from: Hydron on January 27, 2021, 09:55:48 am

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.

BroMarduk · « **Reply #59 on:** January 29, 2021, 03:29:42 pm »

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

.

McBryce · « **Reply #60 on:** January 29, 2021, 03:38:19 pm »

The "layout" is so simple, I just "etched" the separators on a blank double-sided PCB with a hacksaw.

McBryce.

ozkarah · « **Reply #61 on:** March 13, 2023, 09:36:49 pm »

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://www.aliexpress.com/item/32472482265.html

Here are the pics:

McBryce · « **Reply #62 on:** March 14, 2023, 08:24:18 am »

Quote from: ozkarah on March 13, 2023, 09:36:49 pm

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://www.aliexpress.com/item/32472482265.html

Very cool improvements!

McBryce.

ozkarah · « **Reply #63 on:** March 14, 2023, 12:07:04 pm »

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

mawyatt · « **Reply #64 on:** March 14, 2023, 02:55:34 pm »

Quote from: ozkarah on March 13, 2023, 09:36:49 pm

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://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

Electro Fan · « **Reply #65 on:** August 23, 2023, 02:46:10 am »

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

David Hess · « **Reply #66 on:** August 24, 2023, 08:22:01 am »

I am planning on shielding both sides, but shielding the driven signal might not matter. That project is sitting on my workbench again.

audiotubes · « **Reply #67 on:** December 28, 2023, 09:26:07 pm »

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.

korlatos · « **Reply #68 on:** December 29, 2023, 05:48:50 pm »

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.

ufocia · « **Reply #69 on:** February 20, 2024, 05:13:01 am »

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.


EEVblog Main Site	EEVblog on Youtube	EEVblog on Twitter	EEVblog on Facebook	EEVblog on Odysee

Author Topic: DE-5000 LCR TL-21 mod. (Read 23963 times)

Share me