Thanks, Jason. I already have the English version. Unfortunately it offers no help.
Because I can't upload the boot video, I shall describe what happens:
1. Most times, bAtt shows directly upon power up.
2. Holding pressed the HOLD button and turning on shows, first all characters for under 2s., and then "1.02". Releasing the HOLD button reverts to bAtt.
3.Holding Min/Max similarly results in "bEEp" first, and releasing gives " - - - -, and bar graph" for an instant before going bAtt. This is not consistent, going bAtt directly some times.
4. Holding RANGE, the YELLOW button, and the BACKLIGHT produce the same results as 3., except that bEEp is replaced by "LCAP", "PoFF", and "LoFF" respectively.
Note that the "F-116/Err" did not report in this message; today, it did show but once. Earlier, I have seen it alternating F-116 and Err ad infinitum. The F-116 itself is sometimes "F-11-" instead.
Any video would at best show part of this description.
May be this post leads to something?