How to lose most of an an entire collection in one shot

That's not a lot of help _now_ (and nor is board-swapping, whatever your moral views on doing it. If you can't get known-good working boardsm you can't swap them). In fact HP put a test connector inside on the CPU control (microcode) PCB. Amongst other things it carries the 8 bit microcode address. Looking at that -- even just seeing if it executes certain microinstructions -- is a great help in debugging a faulty machine. Well, provided you understnad the processor and have the microcode listings it is :-) Oh I see.... :-( I, alas, have the same problem for rather different reasons (no ladies involved...). Fortunatley when I had spare money, I bought good tools and test gear, and I've got a numnber of machiens around that need reapiring, so I'ev got plenty to keep me busy. What's the difference? I am serious. Apart from the keyboard interface, they're pretty much the same machine, just differently laid out. Even the ROMs are the same between the HP120 and one version of the HP125. The keyboard interface is physically very diffeernt, but the keyboards are logically fairly similar, to the extend you can use an HP125 keyboard on an HP120 with a 3-chip circuit (all 4000-series CMOS parts), although the reverse is a lot harder. OK, there's no official way to have an internal printer in a 120, but the interface is there, and althohgh I've not tried it, it should work. One day I'll borrow bits fro man HP150 and see. When I said I didn't like the design of the HP120, I didn't mean the 'looks ' of the machine. I meant the electronic design -- a separate terminal processor communicating with the application processor through a little 'mailbox' and a very strange video circuit. -tony