What goes wrong with such guns?
Probably overheated and then the resistor block inside goes skew and blocks
the melt flow path. While molten but switched off , a rod through the nozzle
hits something solid , probably ceramic of a wire-wound. When powered,
pushing a hot-melt rod in the entry hole, little exudes from the nozzle,
requiring greater force than usual, outer housing seems to have expanded a
bit as well.
When I get a new one , this one will have a PM, but in the meantime , if
anyone has been inside one before.