6 Dec
2005
6 Dec
'05
12:51 a.m.
Hi list,
You may remember the big stack of HP85s/HP86Bs I pulled from a
dumpster a few months ago.
They've been stored away safely since then, and now I'd like to get
started testing them so that I can get them sold. Tony recommended
running the power supplies on a dummy load to make sure that none of
them are duds. I have a handy bag of Big Resistors that I can make
dummy loads out of, however, (in an 86B at least, I've not been into
the 85s yet) there's a 10-conductor cable coming out of the PSU and
I've no idea what sort of load it might want to see and on which pins.
Googling for the service manual hasn't been productive.
Can anyone advise? I have the basic tools (multimeter etc., and some
cantankerous old oscilloscopes) but don't have any experience doing
this sort of thing.
Thanks,
Ed.
6 Dec
6 Dec
2:46 a.m.
On Monday 05 December 2005 16:51, listmailgoeshere at gmail.com wrote:
Hi list,
You may remember the big stack of HP85s/HP86Bs I pulled from a
dumpster a few months ago.
They've been stored away safely since then, and now I'd like to get
started testing them so that I can get them sold. Tony recommended
running the power supplies on a dummy load to make sure that none of
them are duds. I have a handy bag of Big Resistors that I can make
dummy loads out of, however, (in an 86B at least, I've not been into
the 85s yet) there's a 10-conductor cable coming out of the PSU and
I've no idea what sort of load it might want to see and on which pins.
Get the service manuals, etc. off of the DVD produced by "The Museum of HP
Calculators":
http://www.hpmuseum.org/
There's lots of wonderful infomation on options, Journal articles, etc. on the
DVD.
Cheers,
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
Mountain View, CA
http://bickleywest.com
"Black holes are where God is dividing by zero"
2:23 p.m.
On 12/6/05, Lyle Bickley <lbickley at bickleywest.com> wrote:
On Monday 05 December 2005 16:51, listmailgoeshere at
gmail.com wrote:
Sadly I can't afford to spend any money on these systems. I didn't
rescue them to keep - I rescued them to move them on to new homes. I'm
not averse to spending the time to test them before said rehoming, but
I can't spend any Cash Money(tm) on them.
Ed.
They've been stored away safely since then,
and now I'd like to get
started testing them so that I can get them sold. Tony recommended
running the power supplies on a dummy load to make sure that none of
them are duds. I have a handy bag of Big Resistors that I can make
dummy loads out of, however, (in an 86B at least, I've not been into
the 85s yet) there's a 10-conductor cable coming out of the PSU and
I've no idea what sort of load it might want to see and on which pins.
Get the service manuals, etc. off of the DVD produced by "The Museum of HP
Calculators": 
6:23 p.m.
Get the service manuals, etc. off of the DVD produced
by "The Museum of HP
Calculators":
http://www.hpmuseum.org/
I don;t normally like electronic documentation (much prefering it on
paper...) but that set of CD-ROMs (I don't have a DVD-ROM drive, so I
bougth the 10 CD set) wsa well worth the money. It's about what you'd pay
for a couple of manuals at some places... If you like HP calculators and
small computers, you need these disks.
For larger HP machines, and peripherals (including printers and plotters)
there's a lot of free scanned manuals (pdf format) on
http://www.hpmuseum.net. Of course many of the service manuals are
boardswapper guides, but I find it quite amusing to read those and then
work out how to do the job properly :-)
-tony
6:18 p.m.
Hi list,
You may remember the big stack of HP85s/HP86Bs I pulled from a
dumpster a few months ago.
They've been stored away safely since then, and now I'd like to get
started testing them so that I can get them sold. Tony recommended
running the power supplies on a dummy load to make sure that none of
them are duds. I have a handy bag of Big Resistors that I can make
dummy loads out of, however, (in an 86B at least, I've not been into
the 85s yet) there's a 10-conductor cable coming out of the PSU and
I've no idea what sort of load it might want to see and on which pins.
Googling for the service manual hasn't been productive.
The HP86B service manual and a reverse engineered scheamtic (which
includes PSU pinouts) is on http://www.hpmuseum.net . From what I
remember, this PSU is happy with no load at all -- just pull the cable
that links it to the logic board, power up, and check the output voltages
wrt the ground pin on the connector.
The HP85 is a bit harder. The service manual is available on the MoHPC
CD-ROM set (http://www.hpmuseum.org), but you have to buy that. It's not
on hpmuseum.net. And because I have the manual, I didn't produce my own
schematic for that one.
The other problem with the 85 is that the PSU is on the same board as the
printer circuity, and it's hard to get to between the printer/tape drive
asembly on the right and the monitor assembly on the left. Really, you
need to pull the 40 pin custom printer controller chip from the PSU board
before testing it (yes, it is socketed).
The PSU/peinter PCB is connected to the logic PCB (under the keyboard) by
2 bits of tapewire. You will need to swing the keyboard up (undo the 2
screws on the bracket behind the keyboard) to get access to this. The
connectiosn, according to the service manual, are :
Rear
J8 J9
GndH --o o-- +12H
Phi_2 --o o-- +12H
GndH --o o-- Phi_1
Phi_21--o o-- GndL
GndL --o o-- GndL
+5 --o o-- PWO4
B7 --o o-- GndL
GndL --o o-- B6
B5 --o o-- +6
-12 --o o-- B4
B3 --o o-- +12L
+6 --o o-- B2
B1 --o o-- +5
-5 --o o-- B0
Rd/ --o o-- GndL
+32 --o o-- Wr/
LMA/ --o o-- PSS
You can ignrore all siognals other than +12L, +12H, +6, +5, -5, -12 and
+32 (which are the PSU outputs). The 2 groudns (GndH and GndL) are linked
on the PSU board, as are the 2 +12V lines. The +32V line is ungegulated,
so don't worry too much about that.
All the other signals are the system bus to the printer control chip.
Oh, one other trick. When removing the top on an HP85, pull off the
tape drive eject button first.
-tony
6976
days inactive
6976
days old
4 comments
3 participants
participants (3)
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ard＠p850ug1.demon.co.uk -
lbickley＠bickleywest.com -
listmailgoeshere＠gmail.com