HP 9000/216

Tony Duell ard at p850ug1.demon.co.uk
Tue Dec 4 16:05:35 CST 2007


> 
> I finally decided to pick up the HP 9000/216 box which had been laying 
> around at my usual supplier for a few weeks.  I spent a little time 
> looking at google, and can't find much info on them.

The first trap for the unwary is that this machine also goes under the 
number 'HP9816'. Maybe a search for that would be more helpful. For the 
record : 
HP9000/226 == HP9826
HP9000/236 == HP9836
HP9000/217 == HP9817 
too.

Go to http://www.hpmuseum.net/ . I don't think there's much 
machine-spcific infopr fo the 9816 on that site, but there should be 
things like HP BASIC disks for the 9000/200 family (of which this is a 
member). And if you can stick my handwritinmg, there should be a set of 
schematics.

 
> >From physical examination, it looks like it has a 1MB and a 256kB 
> expansion memory card (so 1.5MB total), and a fairly large keyboard, 

It's a beautiful little machine IMHO, built very well. It's possible to 
remove all the PCBs apart form the PSU only having to remove 1 screw, for 
example.

There are 6 PCBs (and 2 expansion slots) packed into that little 
case.Flat in the bottom there's the processor board, which also contains 
RAM, boot ROMs, RS232 and HPIB ports, keyboard interface, etc. That plugs 
into a little backplane with 2 DIO slots. DIO is the HP expansion bus for 
the 9000/200 series. physically it's the same connectors as S100 bus, but 
the PCBs are smaller, and the signals totally different. It's basically 
the 68000 bus, with lites to talk to an optional DMA controller. The 
power lines are regulated +5V and +/-12V. On top of that assembly is 
another larage PCB mounted horizontally that plugs into the same 
backplane. It cotnains the monitor circuitry and the +/-12V regulators 
(the PSU outptus +/-14V). Plugged into that are 2 small PCbs on the right 
of the CRT (lookinf from the back of the machine), the larger one on the 
left is the text video board (6845 + 4K RAM + character generator + TTL), 
the smalelr one is the graphics board (16K DRAM + TTL). Finally on the 
left of the PCBs is a metal box containing an SMPSU board.

You are lucky if you have a machine with 1M on the CPU board. Most have 
256K (32 off 4164 DRAMs). I figured out when looking at said board that 
it had been designed to take 41256 chips too, so I desoldered all the 
RAMs in mine, replaed them with 41256s (alas you can't use sockets, the 
PCB won't fit under the backplane if you do), fitted a 74F158 mux chip 
and a resistor for the extra address input, and cut a couple of jumpers. 
Only much later did I hear that HP had shipped machines like that.

The 2 DIO slots are wired in prallel. The lower one can take a PCB with 
an external connector (like a GPIO parallel card), the upper one can only 
take 'internal' cards (RAM, DMA controller, ROM, bubble memory, etc).

Without an HP disk drive, it's not going to do a lot (well, if you have a 
ROM BASIC or ROM HPL board in the machine, it'll boot to that, but you 
can't save your programs). You want to track down an HP9122 (dual floppy) 
or HP9133 (floppy/hard disk) or something like that. Thos plug into the 
HPIB interface.

The serial port is a strange connector (50 pin microribbon), but standard 
RS232 signals (once you've worked out where they all are). Finding the 
wirelist of the cable was an entertainment. I finally found it in the 
Pascal standard procedures manaul, it's also in one of the Basic manuals. 
It's not in any specidfically-hardware manual that I could find.

> which is different than the "standard" keyboard that comes with it (it 
> includes a dial at the top left, and has grey keys instead of brown).

Mine came with the samll keyboard. It also has the 'dial', actually a 
rotary encoder. That's used for scrolling. On its own it moves the cursor 
horizontally, if you hold down the shift key it moves it vertically. It 
feels very nice to me.

The keyboard interface is power, ground, clock (processor board to 
keyboard) and a bidirectional line. From the procesor board to keyboard 
it's a reset to clear the scan counter and start a new scan. From 
keyboard to processor, it carries the state of the current key. 

Strangely, for all the keys are scanned by the hardware in the keyboard, 
they are not wired in a matrix. Instead one side of each key is grounded, 
the other goes to an input on a 4051 mux chip (the keyboard is full of 
those!) 

When mine came, it was missing the left shift key and a couple fo the key 
contacts were mangled. I soon realised the latter were the same as used 
in the VT52, VT100, TRS-80 Model 1, etc. Digging in my junk box, I found 
a 'spare' VT52 keyboard PCB from whih I raided some contacts, and parts 
like key plungers to replaced cracked ones. I found the shift key on that 
was the right size, even if the wrong colour and design to fit the 9816 
keybard, so I put it on. If I ever find the right one, I can swap it.

[1] No I didn't raid a repariable VT52. I was given a load of DEC bits, 
and this keyboard was amongst them. I assume somebody else raided a VT52.

I've enver seen the larger keyboard 'in the flesh'. I assume it's 
electrically compatible, although it might well be different internally.

> 
> I was wondering if these are actually somewhat rare, or if they're just 
> not very well sought-after.  If anyone is interested in giving me some

HP9000/200 machines don't seem to have much collector interest, which is 
a pity. I find them all to be very well made, repairable, interesting 
designs. Tracking down expansion boards is a bit of a problem, but when 
you find them, they tend to sell for low prices, thankfully.
 
-tony




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