Here are some pictures of the inside, which show a well laid out PCB with mostly SMD parts and with few glaring issues, in my opinion.
There is only one screw, which fits into a receiving metal insert, holding the back in place, after it has snapped in its position.
There are no screws on the PCB, it fits in a slot at the top of the case and is held in place by plastic clips, which are part of the case.
It has a 400mA fuse for the mA range and a PTC on the other functions, for input protection.
It is a self recovery 250V 400mA fuse overcurrent protector (WH250 400):
http://en.b2b168.com/s168-29888660.htmlPPTC (Polymeric PTC, Polyswitch)
http://en.wikipedia.org/wiki/Resettable_fuseAs you can see, the piezo speaker is sitting just behind the LCD screen, which may explain why the sound is rather faint.
I will test its accuracy against my other meters, when I get home.
This particular meter came from China, left the factory on 20th Nov 2012 and carries a China warranty only, valid for 1 year.
The PCB is quite barren, understandably, with most functions accomplished by U2, the DMM ADC, which is hiding under a blob of black epoxy.
There are no voltage regulators, the ADC works directly off the 3V battery.
The cruciform battery holder looks a bit crude, but it does the job.
4 trim pots can be found:
VR1: DC Volt adjustment
VR2: AC Volt adjustment
VR3: Capacitance adjustment
VR4: DC mA adjustment
The burden voltage on the mA range is 3.45mV/mA and 102uV/uA on the uA range, which is pretty good compared to the UT71D (5.33mV/mA and 500uV/uA). For reference the Fluke 87V has a burden voltage of 1.80mV/mA on the mA range and 102uV/uA on the uA range.
The resistances involved include the current shunt, the polyswitch and the leads (3.45 Ohms on mA and 102 Ohms on uA)
The see-through plastic protective case is a bit bulky, but it shields the meter quite well.
One feature I hadn't noticed, is that the meter can be used with the translucent case closed. There is a clear aperture over the LCD screen and 2 openings in the case for the probe leads to pass through.
So, once the proper selection has been made with the range switch, the case can be closed and the meter can be used in a rough and dirty environment, without having to worry about contamination. It is kind of rainproof, but certainly not waterproof.