Author Topic: DE-5000 LCR TL-21 mod.  (Read 9974 times)

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Offline beowulfenator

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Re: DE-5000 LCR TL-21 mod.
« 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!
 

Offline beowulfenator

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Re: DE-5000 LCR TL-21 mod.
« 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.
 
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Online uski

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Re: DE-5000 LCR TL-21 mod.
« 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 !
 

Offline McBryce

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Re: DE-5000 LCR TL-21 mod.
« 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.

 
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