> It turns out the problem was the cab kit. I replaced it with a spare and the > machine worked great. On closer inspection I found some corrosion and > possible evidence of a previous battery leak, so I am going to take it apart, > check it and clean it up. > > The other thing that made me suspect the cab kit is that the act of pulling the > serial cable out (not unplugging the terminal) would cause the machine to > reset. MicroVAX II does this if you switch off the console terminal while the > terminal is connected. >
Just a bit more info on this. I tried cleaning up the corrosion, and that briefly seemed to make a difference, but then I realised the problem persisted. I looked again and realised that the corrosion around the DE-9 pins was a bit bad. Initially I thought to solder some jumper wires around pins 2 and 3, but when the solder would not melt very easily, I found that it kind of flaked off under a bit of heat and physical pressure. This made me think that although I was getting continuity with my DMM, the joint was not that good. So I desoldered the whole DE-9 connector, cleaned the board with PCB cleaner and then resoldered it back. This seems to have fixed it. Regards Rob
