Hi guys! I came across with a kind of pretty weird difficulties when started a new pair of T12' tips ('B' series - short cone shaped for small SMD's). So when I stuck them into the handles (got a pair of it powered from single ATX power supply DIY structure based on Chinese 'T12 soldering station kit' bought on AliExpress - I often use it as a soldering tweezers) - both of them 'speed up' themselves in a very 'peculiar way' as D. Bowie sang. Well, firstly I got '500' on both displays for a few seconds, then '450' (in spite the target temperature has been set to '250' or so). This lasted for a half of a minute, then tips began to warmed up slowly, but in a few minutes they hardly managed to melt a small piece of rosin. Then I got tired of it and set the target temperature to maximum (450 C), and, in the end, in a pair of a minutes (as usual it gains its target temp. in a few SECONDS) I've got a pair of pretty good T12 tips that works just perfectly, as ever. Then I set the target down to 250 C, then switched it off, let them cool down to the ambient, and then run them again... Any problem! So now they work just as any other ordinary T12 tip. So now here is my question: is anyone ever faced this and whether somebody has a kind of plausible explanation of the phenomena? Thank you!