Mark, Homebrewed
Problem with RPM Display fixed.
I felt I owed it to you to let you know the outcome of this issue after you both contributed so much of your time helping me with it.
Following your suggestion, I replaced the BD107 bridge rectifier and the 78L05 voltage regulator and there was no further problem with the display during several hours of use today. After running the module on batteries without trouble prior to this, it seemed this was the only thing left to try. It seems likely that it was after all, a thermal intermittent fault with one or both of those components. I would have replaced one at a time and re-tested but I got lazy. Anyway, all's well now.
Thank you both once again for all your help.
Trevor
