I have one of these testers that I got as a Banggood kit in October 2015. It was working well, but over a few minutes today the screen lost most, and then all, contrast. As a result, I can't bring up its menu to adjust the contrast, because I can't tell where in the menu system I am, or if I've even got into it. Installing a fresh battery doesn't help.
Because I can't interrogate it through its own menus, I can't tell what version of the software it has. FWIW, it has a 1" x 2" blue/white monochrome graphic screen and a 28-pin ZIF socket on a 2.5" x 3" red PCB. The processor is an ATMega328.
Of course, the display unit could have irreversibly failed, in which case I'll just get a whole new kit from Banggood (or elsewhere, if the old tester hands here have a recommendation). Before I do that, is there a reset worth attempting?