cctech Digest, Vol 96, Issue 5

Or alternaticely, erminals are genrally much easier to repair to compoent level than PCs. On my desk I haev (all operational) : The hacked 5170 I am typing this on, and which I've described many times before The 5160 I just mentioned with 4 floppy drives, 2 hard drives, MDA and CGA cards, 4 serial ports, 24 line user I/O (8255-based), etc. Not all orignial IBM of course, although much fo the machine, incuding the motherboard and keyboard are. A CoCo 3 (512K, 2 drives, serial port, etc) A PDP8/e with 32K words of real core, EAE boards, RK8e (not connected to anything at the momnet), TU56, PC04 and RX01. I think all of those would count as classic computers. The best place to get information on these machines is http://www.hpmuseum.net/ . Youy cna download a fair amount of docuemtation... I find that hard to believe for one good reason. The HP9820 never ran BASIC... The HP9820 was HP's first infix-notation (as opposed to RPN/postfix) calculator and used a language that developed into the 'HPL' of the 9825 etc. The HP9830 was the machine in that family that ran BASIC. In many ways it's the first personal computer, in that it was the first all-in-one machine that you simply put on a desk, plugged into the mains, turned on and started programming in BASIC. You may have guessed I have something of a soft spot for these machines. I own a 9810 (3 level stack RPN), 9820 amd 9830, and a considerable number of the interfaces. One of my long-term goals is to get an HP9880 disk system for the 9830. Things I like about them include : -- They're one of the few bit-serial machines you are likely to find (they're a lot more common than a PDP8/s for example) and that in itself makes them interesting to me -- The CPU is built mostly from TTL (there's no single-chip microprocessor), so you can dive in with the logic analyser. On the other hand, the machines are small enough to be easy to accomodate, unlike, say a rack mounted minicomputer -- They have the legendary HP build quality and though-out design. -- Most faults can be easily fixed. Most of the electronic parts are still easy to obtain -- the only custom ICs are the ROMs. The RAMs (1103 1K*1 DRAMs) are hard to find, though. The displays can fail and are vry hard to get. But the TTL logic for the CPU and memory control is not a problem. Debugging them is not too hard, but you do need a logic analyser. Mechanical problems are normally just decayed rubber parts (card reader rollers, printer platten), they can be replaced without too much work. -- A purely selfish rason. They are HP calculators, at least in name, and are on the fringe of what HPCC (http://www.hpcc.org/) covers. This group is the only place where I get to meet like-minded people, and while I would have problems if I wanted to chat about PDP11s all the time, I can get away with mentionign the HP9830 ;-) There are also some pictures on the aforemntioned site, and in my flickr accound (tony_duell). The latter contains no pictures of the complete machine, but it does show all the plug-in PCBs, repairing the printr and card reader, etc. -tony