The Aoyue 937+ is a temperature controlled soldering iron, somewhat styled after the Hakko series.
I purchased this on the recommendation of the seller that it was a good, practical and reliable product.
The sodlering iron when powered up out of the box was set to 200°C, and duly heated quickly to that temperature.
A set of up/down buttons allow adjustment in 2°C steps. When held down, these buttons repeat rapidly, too rapidly to be able to stop in time for a target temperature.
There is also a * button to jump to a 'default' temperature.
It turns out that the controller does not remember the target
temperature when it is switched off, returning to 200°C. There seems no
method for the user to set the default temperature.
The buttons proved unreliable, a common problem is low quality tactile switches with age. Dissasembling the control unit revealed a brown residue in many places on the board, and the tactile switches showed signs of exterior rusting. I do not know if internal rust was the reason for poor contact. The rust can be seen in the picture, as can the residue around the 100µF capacitor.
After cleaning the board, especially the switches, with alcohol, the board was dried with compressed air and the power unit reassembled. It has since worked reliably.
Overall, usability is very poor because of the inability to remember a 'favourite' operating temperature, and the clumsiness of the temperature adjustment controls. It was noted whilst the unit was dismantled that it is controlled by an MCS51 series microcontroller which seems to not have EEPROM, nor does there appear to be EEPROM or the like on board, so there is no place for storage of a default operating temperature other than the hard coded 200°C.
The supplied spindle to support a roll of solder as shown was in fact three separate pieces that fell apart when handled. That was fixed with a spot of glue, but a bigger problem is that the plastic is not heat resistant and it is very easy to damage if touched with the soldering iron, or if the soldering iron is stowed incorrectly and rests on the empty spindle.
All in all, a design that would appear to be by a designer who has
not used a soldering iron, it is impractical in every sense of the
word, built with unsuitable and low quality materials and processes.
Indeed, it questions Aoyue's understanding of soldering products. I
raised my concerns on Auoyue's web site comments page, but no response.
One to avoid!
I replaced it with a Ständig 937D which uses a pot to set the temperature and a digital display of the set / actual temperature. The replacement cost 55% and works much better, it is practical and convenient.17/04/11
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