ytsuji@wucc.waseda.ac.jp (Y.Tsuji) (05/28/91)
If you had used the right connector, you could not have fed 12 volts to 5 volts. Well, I have done this many times in the past, but managed everytime by sheer luck. (1) feeding 5 V to 12 V does no hard, so forget this. (2) feeding 12V to 5V circuit creates eternal damage to components. Transistors, resistors and capacitors usually survive (unless they have the specification of '8V' or something that means below 12 V). The IC's go erratic at 5.5 V and most of them got killed at 7 V. So all you can do is to have a LOGIC PULSER ready and test all the default signals of IC's on the board that have been fed with 12 V. The logic pulser is a convenient tool costing US$30 or less that tells you the logic level of IC pins by simply touching them. Ah, you will need a TTL handbook. If most of the affected chips are custom made chips, you cannot usually cope because they cannot be replaced easily. I wish you a good luck. Tsuji