23 Nov
2013
23 Nov
'13
1:05 p.m.
I remember using a PERQ during my brief time at ICL in
early 1985. I'd love
to see one in operation again.
They are very interesting machines, although many in the UK were wasted
running PNX (PERQ Unix). Quite honestly, if you want a unix box there are
other choices. PERQs are fun when they run the OSes designed for them.
I am not sure where you'd find one now. I am cetainly keeping all four of
mine (!).
[Back to the HP150]
This one does not have the printer.
Does it have the ribbon cable for the printer (it plugs into both the
backpalne and the PSU board)? I might be able to find a spare HP2674
pritner unit, but I know I don;'t have the cable. It could easily be
made, though.
There seems to be a lot plating between the capacitors
and the CRT neck, it
There is a metal bracket, but IIRC not all machines had it (or perhaps
it's HP120s, much the xame casing/PSU/monitor, that was often missing
this shield between the PSU and the CRT neck). But anyway it can't hurt
to check.
really would have to be a heck of an explosion to
damage the tube from what
I can see. I struggled to get the PSU out until I found the service manual
section. From what I can see all the capacitors look OK though.
Good. That is, of course, a switch-mode PSU, and most of the circuitry is
on the mains side of the isolation barrier. Much like the part of thr
H7140 you are working on...
I mentioned getting insdie the card cage yesterday., You want ot do that
to
see what you have. It';s worth seeing if you
have n expansion boards.
Sadly, no expansion cards. I took out the top card from the card cage because the
batteries have leaked
Tht is the video board. There are a couple of 40 pin ICs on it, one is a
CRT9007 CRT controller used for the text display. The other is HP custom
1820-3091, and is the graphics controller. I think that's the only true
custom (as opposed to programemd) IC in the machine.
and there is corrosion on the contact. Thankfully it
does not seem to have
Right This is not uncommon, normally a good scrape cures it. .
done any damage though. One of the caps on the board
has a corroded lead
though. The other card looks fine.
FWIW,. the batteries conenct on the video bord, but the votlage is not
used there. The -ve side of the battery is groudned, the +ve side goes ot
a couple of adjacent pins on the backplane conenctor. It hen goes over
the backplane to the CPU board where it feeds into a diode circuit and
powers the real time clock IC (MM58167). It also ends up on the expansion
board connectors, but I'ev yet to find an expansion board that uses the
battery voltage.
Yes I have already read about the config side of
things. Hopefully while I
source a battery it will work when I power it on.
That batteries are nto ahrd to get. You have the palstic holder with the
spring contact in it, I hope. You need 2 size N cells. These are also
known as 'ladies' (particularly in continental Europe) or LR1 cells.
I ampretty sure Farnell do them. THe Maplin I was in today had a pack of
2 on the rack. Many supermarkets keep them. At least one 'pounds shop'
sells a pack of 5 obtects -- 2 N cells, 2 A23 12V batteris (about the
same size) and one A27 12V battery (smaller). If you get the last pack,
do be sure to ptu the 1.5V cells in the HP150. You do not want to apply
13.5V or worse 24V to the real time clock IC. I would got as far as to
check the voltage across the open ends of the battery nnit before putting
the holder into the machine. It only takes a few seconds.
One common problem is touchscreen errors. Most of the time this is just
dirt collecing in the holes and block the light beak. Occasionally the IR
LEDs and phototranssitors fail. But it is not too hard to sort out, and
the parts are available.
-tony