HP-25 not working

[kohli_vie]

i had the same problem.
i buy (for my memory corner from the 70ths) a HP-25 which doesnt work.

as some user wrote previous, corrosion (maybe from accumulator acid) was the problem, blue tracks)
after some reengineering (to easier find the points to measure) i remove the wrong repair try from the previos owner, and find 2 of the internal power tracks are damaged

you find a lot of information in the WWW
in my opinion, the best is (because you have all pin numbers from the ICs):
https://archived.hpcalc.org/laporte/Wood..._intro.htm

good luck