After switching on the rather old (early 2011 on stick inside) hps140, the screen lits up, but nothing is visible on it. The typical clicking sounds can be heard.
I have seen that you suggest battery being dead in a similar (blank screen) post, and the unit was off for a year or so, some time in relative cold (6C); however, here the screen lits up, and even if I provide external voltage through icsp, same situation.
Can you confirm that these symptoms are consistent with dead battery, or suggest alternative treatment? If you still think it is battery, can be this confirmed by some externally brought voltage/current before I order battery replacement?
Best way to verify is to screw open the HPS140 and unplug the battery. Then power the HPS140 only with the usb cable that was supplied with it (or with an adapter).
Actually, the battery appears good now (voltage on it and after voltage regulator), anyway. From many attempt, the device starts up well (Velleman logo) and works in very few cases (no idea what triggers that), and in few of these there was an additioal horizontal line (or several) on the screen, and in one case, the screen was shifted up by some amount and some characters unreadable.
But in vast majority of cases, screen just lits up and sound clicks.