SMT soldeer- en désoldeergereedschap worden steeds toegankelijker, ook voor hobbyisten. Waar tot enkele jaren geleden een reflow oven reflowoven de standaard was voor een klein lab, tegenwoordig zijn hot plates steeds meer in trek voor SMD soldeerklussen. Dat is te begrijpen omdat hot plates compacter zijn dan reflowovens en desondanks toch heel goede resultaten geven bij het bouwen van prototypes en bij kleinschalige serieproductie.

Hot plates zijn daarnaast ook praktisch te gebruiken bij het solderen aan grote kopervlakken zoals aardvlakken. Als het kopervlak of de printplaat wordt voorverwarmd met hulp van een hot plate gaat het solderen veel makkelijker.

Rework & Reparatie

Reparatieafdelingen gebruiken hot plates bij het vervangen van grote chips in bijvoorbeeld telefoons en tablet. Omdat het hier kleine prints betreft voldoet een klein model hot plate waarmee slechts een klein oppervlak verwarmd wordt. Ik kreeg zo’n mini model om te reviewen, de Miniware MHP50. Het getal 50 geeft hier het bruikbare oppervlak aan: 50 mm bij 50 mm. Dit is nog niet de kleinste hot plate die Miniware levert, er is ook nog een 30 mm by 30 mm versie.
 
miniware mhp50 dimension
The MHP50 wearing its protective silicon hat.

The Miniware MHP50 Is So Cute!

Miniware always puts a lot of effort in product aesthetics and packaging, and the MHP50 is no exception. Opening the orange and black box reveals a manual (in Chinese, English, and Russian). Underneath it, are the hot plate and the USB-C power cable, protected by thick, dense foam. A power supply is not included.

The first impression when taking the MHP50 out of the box is: So cute! It looks like a toy weighing scale for a children’s grocery shop with plastic fruits and vegetables, except that it is rather heavy (170 grams). There is a pushbutton on each side of a small color display. The hot plate itself is protected by a silicon cover.

Flexible Power Supply Options

On the rear side are two power supply connectors, one USB-C (PD) and one barrel jack (DC5525), compatible with certain laptop power adapters. Both worked for me. Using the DC5525 connector, the hot plate can consume up to 150 W, with a PD supply it consumes up to 100 W. The USB connector also serves for firmware updates, and you change the boot image.

The bigger the power supply, the faster the MHP50 heats up. With my 50-W PD supply it took almost five minutes to heat up to 220 °C. My laptop supply is only 65 W, but it heated up much faster, only two minutes. According to the manual, it needs 150 s at full power to heat up to 300 °C.
 
miniware mhp50 reflow mode
Reflow mode, phase C ('welding') almost terminated.

Powering On the Miniware MHP50

The only way to switch on the MHP50 is by switching on the power supply. The device switches itself off after a certain idling time. To switch it back on, you must power-cycle the power supply (or unplug before reconnecting).

It switches on in Heat mode. An RGB LED above the display lights up green. Using the two pushbuttons you change to Reflow, Menu (configuration) and Info. A long press on one of the buttons activates the selected mode (Enter). Another long press on the right button exits the activated mode (Return). A long press on the left button selects parameters in the configuration menu. This is all straightforward and intuitive.

Info Page

The Info page is practical as it shows also the current temperature of the plate and the speed of the (silent) fan, besides the firmware version. This is practical when it is cooling down after leaving Heat mode.

Heating Mode

After entering Heat mode, the MHP50 starts heating up to preset temperature T1. In this mode it displays the current temperature, the input voltage, the target temperature and the time elapsed since entering this mode. There is also a bar graph showing the current power consumption. When the MHP50 is hot, the RGB LED turns red.

Pressing the left button lets you select another preset (three are available), pressing the right button resets the time. After a long press on the left button, you can set the temperature.

Tilt Alarm

Probably because the MHP50 is small and can be knocked over easily, an alarm sounds when the device tilts more than 30° (default, this value is adjustable).

Miniware MHP50 Has Reflow Mode

To enter Reflow mode, the plate must be cooler than 100 °C. In this mode, the MHP50 heats up according to the preset 3-phase curve. You can program this curve in two ways: either by going through the configuration menu or by connecting the hot plate to a computer and then edit its config.txt file. This is a nice feature as it lets you create a library of configuration files. When connected to a computer, the pushbuttons no longer work.
 
miniware mhp50 disassembled
The heater is removable.

Removable Hot Plate

A last feature to mention is that the heating assembly is removable, simply by pulling it off. Not only does this allow for easier cleaning, but it also lets you replace it by another plate. Miniware carries two models, black coated ceramic (what I tried) and bronze, but they don’t explain which one is best in what situation.

Conclusion

The Miniware MHP50 is an easy-to-use well-made, cute little hot plate that can heat up a printed circuit board for rework (or keep your coffee hot; baking a tiny pizza should even be possible). Its reflow mode makes it suitable for assembling small boards. And being small and coming in a charming box, it is easily stored away when not needed.