DMM XL830L

DSC_2801

This is a really cheap DMM with manual ranges and a minimum of functions.

DSC_2794

There was no box included with the DMM.

DSC_2795

It included the DMM, a pair of probes and a instruction sheet.
The instuction sheet includes specifications for AAC and capacity, two ranges the meter do not have.

DSC_2800

The standard probes are rather tiny.

DSC_2799

They use 4mm plugs, but they are not shrouded.

DSC_2803 DSC_2813

When using the tilting bale the DMM requires two hand to turn the range switch, when laying down it depends on the surface. The meter is very smooth on the back and will easily slide around.

DSC_2804
DSC_2805
DSC_2806
DSC_2802




Display

DSC_2811
DSC_2812

Typical display during usage, it will show the number and what range is selected (i.e. 2 in the picture above).
The lightning symnbol is only shown in the 600V ranges.



Functions

DSC_2809

Buttons:
Rotary switch:


Input

DSC_2808



Measurements

DMMschema

I do not believe the specified tolerances, the included manual did not match the DMM.
On 10A range the shunt will heat up and the meter go slightly out of tolerance.



Tear down

DSC_2827

Two screws and the back could be removed, I did also remove the battery cover due to the battery and battery connection wire.

DSC_2830

Four more screws to remove the circuit board, the buzzer and the backlight module. The LCD display is the tinted glass that still is in the meter.

DSC_2828

There is not much support of the input terminals to see here. The buzzer is mounted in the box and connected with two wires, there are also wires to the backlight module.

DSC_2829

The support for the input terminals is here.

DSC_2831

The zebra stribe that connects the display to the circuit board can be seen here (The pink part) and the two buttons.

DSC_2832

One this side of the circuit board is the range switch, the two buttons and the transistor tester socket.

DSC_2833

This is where everything is, the DMM chip is a COP (Chip on board, i.e. chip mounted and bounded directly on circuit board, then sealed).
Being manual range this meter probably has resistors for each range.
RCU & R24: Shunt for 10A (On most meters this is a short wire). R11: Current shut for 200mA, R12: Current shunt for 20mA, R6: 2mA shunt for 2mA, R7: shunt for 200uA.
In DCV input goes to R10 and in ACV input goes to D1, this is the reason for only high AC voltage, the meter uses a normal diode for rectification.
The PTC1 is input protection. Q3 is for driving the backlight.
The fuse is soldered in and is only used on uA and mA ranges.
There is only a single trimmer, this means the precision depends on how precise the parts (resistors) are.

DSC_2834
DSC_2835
DSC_2837
DSC_2836





Conclusion

The CAT rating is fairly low, but I doubt it is valid, because the meter is unfused and lacks protection.
This is a simple and cheap DMM without any real input protection and with only a few ranges. This may be enough for some applications, but keep it away from mains voltage.
Calibration is generally good, that means many ranges are within 1 to 3 count.



Notes

This meter exist with many different names on it and small variations in functions.

How do I review a DMM
More DMM reviews