Help needed: HP 67 repair

[Marcovecchio]

I still didn't study the signals, but the C segment problem seems to be related to the transistors near the display: when I removed them, segments G turned off, and segments C started to behave correctly. I'll try cleaning the board somehow, specially under the display LEDs, probably I have some kind of short between C and G lines.

And I think I have damage on the ROMs: the calculator behaves the same exact way with or without any of the 8 pin ROMs. But I'll try to investigate more and find out where exactly the problems are.

Thanks!

Eduardo