This was bought from Maplin a few years ago for £29.99, (about $50 US). It is a rebadged All-Sun EM6000, currently retailing for around $75. It's a curious mixture of good and bad features which I thought might make an interesting subject for a teardown.
Here is the meter, branded as a "Precision Gold N56FU":
It's a 6000-count instrument with a quoted accuracy of around 0.5%. The blue rubber holster is removable.
A nice large LCD with clear digits, a decent backlight and a bar graph. Less impressive is the substantial voltage displayed with an open input.
Date codes suggest the meter was built in 2008 and measured accuracy on the volts and ohms ranges is still well within spec.
The meter features data logging via a built-in USB interface:
It also has a transistor hFE measurement range, but no onboard sockets. It avoids the complaint of many forum members that this feature compromises safety by utilising a plug-in adapter which doubles as a thermocouple input socket:
The tilting bail is fairly substantial and works with or without the rubber holster, and the battery compartment is readily accessible via a twist lock door without removing the holster:
Here is the circuit board:
Impressive large HRC fuses with 80kA breaking capacity on both ranges. Substantial traces with decent creepage distances. And rather shoddy split input jacks.
There is a 1N4007 diode bridge on the mA/uA current range, and two PTCs in series on the voltage input. But no MOVs.
Main processor is a Fortune FS9922-DMM4, also used on Uni-T's UT61 meters among many others. The true RMS converter is an AD737, and the board also has a TI TLC2252 rail-to-rail op-amp.
The two battery contact pads in the centre of the board connect to spring terminals on the rear half of the case, and a large spring contacts the case shielding:
The case is fairly sturdy, if a little cheap-feeling, with blast protection ridges at the join.
The USB input is quite interesting:
Optically isolated and contained in its own little transparent case.
The case contains a small board with a Silicon Labs CP210x USB to UART bridge driver fed by a photodiode:
This is the other side of the PCB:
No components apart from the LCD and switch connections.
All in all it offers some interesting design features and a wealth of capability, and there are many more expensive meters with inferior safety. But the lack of MOVs and the cheap input jacks let it down somewhat.