On 17/05/2012, at 6:17 AM, Tony Duell wrote:
Both are programmable, but have only a few built-in functions. Are there
any ROM modules in yours (look on top behind the display)? The maths ROM,
for example, adds logs, SIN/COS/TAN, etc. The machines can work without
any extra ROMs, so not having them is not a disaster.
Yes all three machines have math pacs, and the 9810 has a printer alpha pac.
THose are the common ones. Very useful the are too. The pritner alpha ROM
adds the ability to print alhanumebric characters, if you do a program
listing the steps are given sesnible names, not just the (2 digit octal)
codes , and so on. It must go in the rightmost slot to work. The
HP9820 has this functionality built-in.
The mathcs ROM adds the trig functions, logs, etc. In the 9810, it goes
in the leftmost slot and defines the keypad of half-keys in front of it.
In the 9820 it can go in any slot and defines that slot's block of half
keys. The manuals explain all this.
 The 9810 memory system is a bit odd in that it stores each word in 2
consecutive locations in DRAM, odd bits in one location, even bits i nthe
other. The result is that the physcial emmeoy is only half as wide as yo'd
expect. So the system (stack, etc) and user data regites, which use
logically 16 bit RAM actually have physcial 8 bit RAM (in 8 chuips) and
the progam storage area, which is logically 6 bits wide (to store
keycodes) is physciallyy 3 bits wide. This must be one of the few
machines that takes 2 1103s for a memory upgrade.
This is the original of my talk title 'How many bits make 9810'. YO can
1 - Width of the binary ALY path
3 - Physical width of program memory
4 - Width of the BCD LAU path
6 - Logical width of program memory
8 - Physical width of system memory
16 - Logical width of system memory, CPU register size, etc
The 9820 will have a built-in thermal printer (I
think it's standard on
that model), it's an option on the 9810 (Opt 004 IIRC). It is the same
unit, so if you have no pritner in the 9810 you could move one from one
of the 9820s into it.
The 9810 has the printer option.
RIght. It's farily common (I don't think I've seen a 9918 without it).
It's worth knowing that both machines wil lwortk fine with no printer
installed, I recomend brining up a minimal system to stert with amd get
that going. So start out without the printer, card reader or keyboard
You can get
user manauls, the HP service manaul and some unofficial
scheamtics from http://www.hpmuseum.net/
Thanks, got that stuff now.. With that and your info I should
hopefully be on my way.
You'll get them working. So far I've reapired several 9810s, a 9820 and a
9830 and am helping another guyy fix his 9830 by e-mail. They are
complicated macbines, but not too complciated to understnad.
OI know a little abotu the insides of the machines.
I think that's an understatement, and thanks for all your great (and
Err, yes, well modesty would not let me say something like 'I know as
much as justabotu anyone outide HP, and probably more htan anyoen inside
HP now' :-)
More seriously there are plenty of people who know more than me. One is
on this list...
in depth) information, I'm sure it's going to
be a lot of help.
Initially I think I will probably just clean up the 9810 and one 9820
and board swap (if necessary). I'll sort out th rest at a later date.
You do want me to carry on talking to you, right? :-) Oh, I guess you're
new here and haven't been o nteh end of my antiboardswap[ing rant.
No, I am not going to repost it. All I am going to say is that tese are
fine machiens nad deserve to be fixed properly. And that means amking
measurement,s thinking aobut thosie measurements and then deducing what
the fault is. It's not diffiuclt, and this is an ideal machien to learn
on. I can talk you right through it.
I forgot to mention that I also salvaged a spare card
cage with 4 boards
in it, it's labeled "yellow card faulty", so it may be of some use.
IS this a memory box from one of the machines? If so, which one (they are
very different). If it is, the 'yellow card' is eihther the memroy data
PCB (9810) or memory addres PCB (9820). It can be repaired. If it's a
9820 memory box, it's possible that it was replaed as part of the upgrade
ot the neew RAM suystem (2102 RAMs), which would be interesting. You need
to take a very careful look t what is inside your machines.
HP part numbers for PCBs are quite helphul. THe first 5 digits are the
number of the device the board was first used in, padded with leading
And the board handls of the 9810/20 boards give the last 2 digits of the
part number using the reisstor colour code.
By fr the easiest way I've found ot treacing serious logic faults in
these machines makes use of the test connector on the CPU control PCB
(09810-66513, so brown and orange handles, it's the same in all 9800
machines). This carries the CPU mircocode address bus. Conenct a logic
analyser there and trace the microcode. Of course you need a microcode
source listing to make much sense of it...