My newly acquired HP19C seems to have died on me

[Katie Wasserman]

(11-27-2014 06:28 PM)Harald Wrote:  Are there no 19c expersts present?

I'm not an expert on the 19C, but I'm curious about what you said:
"found the paper arround the printer head had become all blue"

That can/will happen if the paper is exposed to heat or certain chemicals -- isopropyl alcohol for example. If you left the calculator on, perhaps something inside got very hot, was it plugged in to change the batteries? Maybe something failed in the charging circuit, maybe one or more of the cells in the battery pack are shorted.

The stuck-on problem would seem to indicate that the print head driver has at least one bad transistor in it. According to Tony Duell's schematic the 19C uses a single chip transistor array for this, not discrete parts. But it should be possible to bypass the bad transistor in the array with a single NPN.

I've not taken the keyboard apart on the 19C, so don't have any suggestions for that problem.