FNIRSI LCR-ST1 (Inexpensive LCR Tweezers)

[NikNik]

Do you know about any changelog?

I did not find any information about the changes, probably the changes are aimed at improving the accuracy of measurements...
I did not see any changes in the work
+He started to display the polarity of the diode
by turning the icon

[NikNik]

Possible problem and its solution..
I encountered a problem, turned on the device, the line break does not show, the data jumps chaotically, when trying to measure, the readings are unstable, and only when pressing hard does something work more or less reliably, I press even harder, and the readings start jumping again.
I soldered everything on the board that could cause problems.
As it turned out, the problem is in the tips themselves, (in the upper one)...
I drilled a larger hole to center the tips, the hole itself and the base of the probes for insulation (tip) covered with UV nail polish))
the problem is that the installation pin itself shorts to some conductor, as a result of which the measurement mode is disrupted..
after eliminating the problem, the device works stably..

[lownoise]

The installation pin could probably be part of a 4-wire measurement, this would be good news for such a cheap device 

[NikNik]

The installation pin could probably be part of a 4-wire measurement, this would be good news for such a cheap device 

I don't think that's true because the defect appeared when the tip of the probe touched the pin. You can see the insulation around the pin... but it still touched some conductor inside the probe.. I didn't take it apart... I thought if that doesn't solve the problem I'll ask for a replacement..
It's some kind of manufacturing defect.

[Phil1977]

I don't think that's true because the defect appeared when the tip of the probe touched the pin. You can see the insulation around the pin... but it still touched some conductor inside the probe.. I didn't take it apart... I thought if that doesn't solve the problem I'll ask for a replacement..
It's some kind of manufacturing defect.

Please teardown you unit if your seller does not want the defect device to be returned!

I´ve just opened up my ST1 to find out about the tweezer tip connections. Unfortunately I couldn't remove the tweezer sleeves because I didn't want to de-solder them from the mainboard - at least as long as my ST1 is such a nice useful device for super quick identification of SMT parts.

The only thing I could find out is that there are 4 solder connections per side of the tweezer going to the main PCB. One of these connections is directly connected with the tip, none of them seems to be directly connected to the dowel pin.

Does someone know of a teardown where the housing of the tweezer PCBs was removed?

[S2084]

I looked at the spectrum of the test sinusoidal signal at all available frequencies (100, 1000, 10000 Hz)

[TD-er]

I just received my LCR-ST1.
I suspect the internal battery is DoA, as it only allows me to run for 10 seconds. As soon as you disconnect the USB cable, the "full battery" indicator turns red and you see a pop-up countdown to shutdown.

It only draws 7 mA when "charging", which it has been for hours now.

The firmware update ZIP file does have a change-log file in the zip:

LCR-ST1-V1.5-20240827
1. Repair the logic of automatic shutdown setting
2. Add the function of identifying the direction of diode

LCR-ST1-V1.4-20240803
1. Repair the abnormal progress of resistance measurement in some intervals

LCR-ST1-V1.3-20240725
1. Repair some problems of diodes

LCR-ST1-V1.2-20240714
1. Add the function of measuring on and off under diode
2. Add Z and X secondary parameters
3. Add data saving

So far, as long as the USB cable is connected (and connected to some USB hub or power supply), the measurements do seem quite plausible
I do have one of those "resistor/capacitor calibration boards" from Ali.
There are hand-written values on the white silkscreen, suggesting the parts are measured with some calibrated meter.
However the values I measure with this tweezer are quite similar with the written down values and a few I compared with a few other meters I have. (none with "official" calibration certificates)
I just bought this 'test board' to quickly test to see if my meters agree with eachother when in doubt.

[DaneLaw]

I just received my LCR-ST1.
I suspect the internal battery is DoA, as it only allows me to run for 10 seconds. As soon as you disconnect the USB cable, the "full battery" indicator turns red and you see a pop-up countdown to shutdown.

It only draws 7 mA when "charging", which it has been for hours now.

Open it up and check the cell.
If I recall its just a standard of the self 250mAh LIPO they are using.
JHCY 502030
Its around 3€ from EU resellers, but if it arrived defect..and you have a chance to return it... then do that..

[TheDefpom]

I thought I should post my review of them here...

[TD-er]

[...]

Open it up and check the cell.
If I recall its just a standard of the self 250mAh LIPO they are using.
JHCY 502030
Its around 3€ from EU resellers, but if it arrived defect..and you have a chance to return it... then do that..

I have no chance to return it
Even better, Eleshop did send me a new one and I didn't have to return the old one.
It arrived yesterday and immediately you can see it does charge at 200-ish mA and after like half an hour it already stopped charging, so it was like 80% full I guess.

Works perfectly fine.

I will have a look at the defective one and when opened I will take some pictures for whomever also experiences the same issue, or when this battery is eventually dead in like 3 - 5 years.