Importance of "original" parts

On Mon, 8 Dec 1997, Neil McNeight wrote: OK, here's my $0.02... Important to _whom_? I collect computers for one reason and one reason only - I enjoy doing so. I enjoy using them, I enjoy repairing them, and I enjoy hacking them. I do not collect them because I have this belief that in 20 years time I'll be able to sell them and retire on the money. Now, I want to have working computers. That doesn't mean that I only accept working computers, or even only complete computers. It means that I try to repair non-working ones and make/obtain missing parts for incomplete ones. So virtually _all_ machines in my collection are non-original in some way. For example, I have a DEC MINC (Modular INstrument Computer) that I've pulled the 11/03 CPU card from. It's got one end of a DW11-B (Unibus-Qbus interface) in place of said CPU card. The other end of the DW11-B is in my 11/45 CPU. So I now have something that DEC never built - a modular real-time I/O system on an 11/45. Unoriginal? Sure. Interesting, and worth doing? IMHO yes. My IBM PC/AT has also been hacked a lot. There's 2 extra EPROMs on the motherboard containing a patched hard disk table. And a couple of TTL chips to enable them. The IDE card has a piece of stripboard kludged onto it to give it a connector for an 'active' LED - something that was missed out of the original card. The motherboard is the original IBM one, though. IMHO a PC-class machine has to have at least the original motherboard to be 'interesting' (mainly because I have all the IBM schematics and very few others). But my XT's and portables all have the 640K mod done to them. One of my classic PERQs has a QIC-02 interface wire-wrapped in spare space on the I/O card. PERQ systems used another slot for that. And I've not even started on repairs where I tend to use any component that's electrically equivalent (I repair to chip level, so the issue of unoriginal boards doesn't come up). I've used FAST TTL to fix PDP11's. The chopper transistor in one of my VT100 PSUs is not original, and nor are many of the components in my PERQ 1 PSU. My RK11-C has a chip sellotaped to one of the flip-chip cards and linked up with kludge-wires. And so on... I guess what it comes down to is that the architecture _MUST_ be preserved (a pentium motherboard in a DEC BA11-K is a mess!), as far as possible the circuitry must be preserved (so that you do use electrically equivalent components when you do repairs, and don't just swap boards), and mods to improve functionality are fine, even if done today. I'd probably look for an original motherboard, if only because it'd be nice to have one. As to which one I kept in the machine, well, that's up to you. But I'd certainly use the machine as it is now - what have you got to lose? -tony