11 Nov
2016
11 Nov
'16
3:36 p.m.
I acquired a working HP Draftmaster RX (HP part # 7596B).
An awesome machine, 36" roll feed and 8 pens, complete with several pen
carousels, user manual, and hundreds of working pens.
I was very excited to make a splash in the art world with this thing. I did
get it to perfectly draw a 3 color demo page from the front panel.
Thereafter it started displaying errors on the display such as "200" which
means it needs "mechanical calibration".
Thanks to hpmuseum.net I acquired the service manual
<http://www.hpmuseum.net/document.php?hwfile=1292>, which catalogs many
calibrations and self-tests to run from the front panel, including the
aforementioned "mechanical calibration".
So I power up with the appropriate front panel keys depressed to run this
calibration. The paper drive motor starts making noise, but the paper
rollers aren't turning, and the LCD display is blank.
Since that moment, the LCD display is always blank so it is currently a
boat anchor.
It's a terribly sad state of affairs. I have basic electronics and
mechanical skills and an oscilloscope so following the troubleshooting
procedures in the manual I might be able to identify a part to replace. But
of course, parts for sale online are are rare, expensive, used and probably
untested.
Probably better would be lower-level repair of whatever parts are faulty
but that's probably more than I can manage at my skill level.
I'm in Seattle, WA. Is there anyone alive in the pacific NW who will pay a
visit and help me fix this thing? (The only company I found that admits to
working on pen plotters is 360tech in Austin, TX.)
Or someone elsewhere I could ship electronics parts to for test and repair?
Or provide guidance, or help in any form at all?
thanks
M.
11 Nov
11 Nov
3:38 p.m.
How is the power supply? All rails ok? Input/output capacitors not bulged
nor leaked?
2016-11-11 21:36 GMT-02:00 Michael Newton <michael.newton at gmail.com>:
I acquired a working HP Draftmaster RX (HP part #
7596B).
An awesome machine, 36" roll feed and 8 pens, complete with several pen
carousels, user manual, and hundreds of working pens.
I was very excited to make a splash in the art world with this thing. I did
get it to perfectly draw a 3 color demo page from the front panel.
Thereafter it started displaying errors on the display such as "200" which
means it needs "mechanical calibration".
Thanks to hpmuseum.net I acquired the service manual
<http://www.hpmuseum.net/document.php?hwfile=1292>, which catalogs many
calibrations and self-tests to run from the front panel, including the
aforementioned "mechanical calibration".
So I power up with the appropriate front panel keys depressed to run this
calibration. The paper drive motor starts making noise, but the paper
rollers aren't turning, and the LCD display is blank.
Since that moment, the LCD display is always blank so it is currently a
boat anchor.
It's a terribly sad state of affairs. I have basic electronics and
mechanical skills and an oscilloscope so following the troubleshooting
procedures in the manual I might be able to identify a part to replace. But
of course, parts for sale online are are rare, expensive, used and probably
untested.
Probably better would be lower-level repair of whatever parts are faulty
but that's probably more than I can manage at my skill level.
I'm in Seattle, WA. Is there anyone alive in the pacific NW who will pay a
visit and help me fix this thing? (The only company I found that admits to
working on pen plotters is 360tech in Austin, TX.)
Or someone elsewhere I could ship electronics parts to for test and repair?
Or provide guidance, or help in any form at all?
thanks
M.
8:35 p.m.
Thanks for the encouragement. I'm going in.
I found test points on the power supply/motor driver board as detailed in
Chapter 12 of that manual.
+5v, +12v, +15v, +42v and +85v are all there (and all .4v high or so)
But there is no -12v. That seems relevant.
The capacitors all look OK to the naked eye.
Actually diagnosing and repairing electronics is new territory for me, but
I suppose this is where I read up, maybe pull that board out, and start
testing diodes and caps.
Thanks again Alexandre - and if you or anyone else has any clues to narrow
it down, please share.
M.
On Fri, Nov 11, 2016 at 3:38 PM, Alexandre Souza <
alexandre.tabajara at gmail.com> wrote:
How is the power supply? All rails ok? Input/output
capacitors not bulged
nor leaked?
2016-11-11 21:36 GMT-02:00 Michael Newton <michael.newton at gmail.com>:
I acquired a working HP Draftmaster RX (HP part #
7596B).
An awesome machine, 36" roll feed and 8 pens, complete with several pen
carousels, user manual, and hundreds of working pens.
I was very excited to make a splash in the art world with this thing. I
did
get it to perfectly draw a 3 color demo page from
the front panel.
Thereafter it started displaying errors on the display such as "200"
which
means it needs "mechanical
calibration".
Thanks to hpmuseum.net I acquired the service manual
<http://www.hpmuseum.net/document.php?hwfile=1292>, which catalogs many
calibrations and self-tests to run from the front panel, including the
aforementioned "mechanical calibration".
So I power up with the appropriate front panel keys depressed to run this
calibration. The paper drive motor starts making noise, but the paper
rollers aren't turning, and the LCD display is blank.
Since that moment, the LCD display is always blank so it is currently a
boat anchor.
It's a terribly sad state of affairs. I have basic electronics and
mechanical skills and an oscilloscope so following the troubleshooting
procedures in the manual I might be able to identify a part to replace.
But
of course, parts for sale online are are rare,
expensive, used and
probably
untested.
Probably better would be lower-level repair of whatever parts are faulty
but that's probably more than I can manage at my skill level.
I'm in Seattle, WA. Is there anyone alive in the pacific NW who will pay
a
visit and help me fix this thing? (The only
company I found that admits
to
working on pen plotters is 360tech in Austin,
TX.)
Or someone elsewhere I could ship electronics parts to for test and
repair?
Or provide guidance, or help in any form at all?
thanks
M.
9:17 p.m.
Are you saying there is a -12V test point and there is nothing there ?
If +5 is 400mV high, that's not dangerous but it is something I'd take care
of first.
-pete
On Fri, Nov 11, 2016 at 8:35 PM, Michael Newton <michael.newton at gmail.com>
wrote:
Thanks for the encouragement. I'm going in.
I found test points on the power supply/motor driver board as detailed in
Chapter 12 of that manual.
+5v, +12v, +15v, +42v and +85v are all there (and all .4v high or so)
But there is no -12v. That seems relevant.
The capacitors all look OK to the naked eye.
Actually diagnosing and repairing electronics is new territory for me, but
I suppose this is where I read up, maybe pull that board out, and start
testing diodes and caps.
Thanks again Alexandre - and if you or anyone else has any clues to narrow
it down, please share.
M.
On Fri, Nov 11, 2016 at 3:38 PM, Alexandre Souza <
alexandre.tabajara at gmail.com> wrote:
faulty
How is the power supply? All rails ok?
Input/output capacitors not bulged
nor leaked?
2016-11-11 21:36 GMT-02:00 Michael Newton <michael.newton at gmail.com>:
many
I acquired a working HP Draftmaster RX (HP part #
7596B).
An awesome machine, 36" roll feed and 8 pens, complete with several pen
carousels, user manual, and hundreds of working pens.
I was very excited to make a splash in the art world with this thing. I
did
get it to perfectly draw a 3 color demo page from
the front panel.
Thereafter it started displaying errors on the display such as "200"
which
> means it needs "mechanical calibration".
>
> Thanks to hpmuseum.net I acquired the service manual
> <http://www.hpmuseum.net/document.php?hwfile=1292>, which catalogs > calibrations and self-tests to run from the
front panel, including the
> aforementioned "mechanical calibration".
>
> So I power up with the appropriate front panel keys depressed to run
this
calibration. The paper drive motor starts making noise, but the paper
rollers aren't turning, and the LCD display is blank.
Since that moment, the LCD display is always blank so it is currently a
boat anchor.
It's a terribly sad state of affairs. I have basic electronics and
mechanical skills and an oscilloscope so following the troubleshooting
procedures in the manual I might be able to identify a part to replace.
But
of course, parts for sale online are are rare,
expensive, used and
probably
> untested.
>
> Probably better would be lower-level repair of whatever parts are > but that's probably more than I can
manage at my skill level.
>
> I'm in Seattle, WA. Is there anyone alive in the pacific NW who will
pay
a
visit and help me fix this thing? (The only
company I found that admits
to
working on pen plotters is 360tech in Austin,
TX.)
Or someone elsewhere I could ship electronics parts to for test and
repair?
Or provide guidance, or help in any form at all?
thanks
M.
16 Nov
16 Nov
11:34 p.m.
That's right, there is a -5v test point that reads zero.
Any guidance? Like if I need to pull parts off and test them, which ones
might I go for? I'm a caveman with electronics.
M.
On Fri, Nov 11, 2016 at 9:17 PM, Pete Lancashire <pete at petelancashire.com>
wrote:
Are you saying there is a -12V test point and there is
nothing there ?
If +5 is 400mV high, that's not dangerous but it is something I'd take care
of first.
-pete
On Fri, Nov 11, 2016 at 8:35 PM, Michael Newton <michael.newton at gmail.com>
wrote:
the
currently a
admits
Thanks for the encouragement. I'm going in.
I found test points on the power supply/motor driver board as detailed in
Chapter 12 of that manual.
+5v, +12v, +15v, +42v and +85v are all there (and all .4v high or so)
But there is no -12v. That seems relevant.
The capacitors all look OK to the naked eye.
Actually diagnosing and repairing electronics is new territory for me,
but
I suppose this is where I read up, maybe pull
that board out, and start
testing diodes and caps.
Thanks again Alexandre - and if you or anyone else has any clues to
narrow
it down, please share.
M.
On Fri, Nov 11, 2016 at 3:38 PM, Alexandre Souza <
alexandre.tabajara at gmail.com> wrote:
> How is the power supply? All rails ok? Input/output capacitors not
bulged
> nor leaked?
>
> 2016-11-11 21:36 GMT-02:00 Michael Newton <michael.newton at gmail.com>:
>
> > I acquired a working HP Draftmaster RX (HP part # 7596B).
> >
> > An awesome machine, 36" roll feed and 8 pens, complete with several
pen
> > carousels, user manual, and hundreds of
working pens.
> >
> > I was very excited to make a splash in the art world with this
thing. I
did
many
> > calibrations and self-tests to run from the front panel, including get it to perfectly draw a 3 color demo page from
the front panel.
Thereafter it started displaying errors on the display such as "200"
which
> means it needs "mechanical calibration".
>
> Thanks to hpmuseum.net I acquired the service manual
> <http://www.hpmuseum.net/document.php?hwfile=1292>, which catalogs >
aforementioned "mechanical calibration".
>
> So I power up with the appropriate front panel keys depressed to run
this
> > calibration. The paper drive motor starts making noise, but the paper
> > rollers aren't turning, and the LCD display is blank.
> >
> > Since that moment, the LCD display is always blank so it is > > boat anchor.
> >
> > It's a terribly sad state of affairs. I have basic electronics and
> > mechanical skills and an oscilloscope so following the
troubleshooting
> > procedures in the manual I might be
able to identify a part to
replace.
But
faulty
of course, parts for sale online are are rare,
expensive, used and
probably
> untested.
>
> Probably better would be lower-level repair of whatever parts are > but that's probably more than I can
manage at my skill level.
>
> I'm in Seattle, WA. Is there anyone alive in the pacific NW who will
pay
> a
> > visit and help me fix this thing? (The only company I found that to
working on pen plotters is 360tech in Austin,
TX.)
Or someone elsewhere I could ship electronics parts to for test and
repair?
Or provide guidance, or help in any form at all?
thanks
M.
17 Nov
17 Nov
12:10 a.m.
On 2016-Nov-16, at 11:34 PM, Michael Newton wrote:
That's right, there is a -5v test point that reads
zero.
From the previous discussion, presumably you mean -12V.
Any guidance? Like if I need to pull parts off and
test them, which ones
might I go for? I'm a caveman with electronics.
Looking at:
7595-7596_HardwareSupportManual_07595-90025_168pages_Feb90.pdf
from hpmuseum.net via the link you supplied, the
document seems to be truncated.
The document simply ends part way through the
schematics pages, and of course the power supply schematic is missing.
(Aside, where did you find that document link? I didn't find it ref'd on the
hpmuseum pages.)
There is a minimal diagram for the power supply on page 5-4 (pdf.30), which shows the -12V
supply as an independent (not part of the control loop) secondary out of the switching
supply. That's good as it limits the likely problem region. There will be more
components involved than shown there, but the diode seen there on the -12V supply will
lead to a filter cap and possibly a 3-terminal linear regulator such as a 7912 or
LM320-12, or even a zener
regulator. There may be current limiting or overvoltage circuitry between there and the
actual -12 output of the supply.
- identify the -12V componentry in the power supply.
- if there is a 3-terminal -12V regulator check for input to the reg vs output.
- confirm that it's not the load side of the -12 causing the problem.
- pic(s) of the power supply board might help us identify the area or get a better idea
of what we're dealing with.
18 Nov
18 Nov
3:17 p.m.
On Thu, Nov 17, 2016 at 12:10 AM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
It's linked from http://www.hpmuseum.net/collection_document.php - search
the page for "DraftMaster"
The document does appear to be missing the full schematic of the analog
board. I haven't been able to find them anywhere.
On 2016-Nov-16, at 11:34 PM, Michael Newton wrote:
Yes -12v, sorry
That's right, there is a -5v test point that
reads zero.
From the previous discussion, presumably you mean -12V. Any guidance?
Like if I need to pull parts off and test them, which ones
might I go for? I'm a caveman with electronics.
Looking at:
7595-7596_HardwareSupportManual_07595-90025_168pages_Feb90.pdf
from hpmuseum.net via the link you supplied, the document seems to be
truncated.
The document simply ends part way through the schematics pages, and of
course the power supply schematic is missing.
(Aside, where did you find that document link? I didn't find it ref'd on
the hpmuseum pages.)
There is a minimal diagram for the power supply on
page 5-4 (pdf.30),
which shows the -12V supply as an independent (not part of the control
loop) secondary out of the switching supply. That's good as it limits the
likely problem region. There will be more components involved than shown
there, but the diode seen there on the -12V supply will lead to a filter
cap and possibly a 3-terminal linear regulator such as a 7912 or LM320-12,
or even a zener
regulator. There may be current limiting or overvoltage circuitry between
there and the actual -12 output of the supply.
- identify the -12V componentry in the power supply.
- if there is a 3-terminal -12V regulator check for input to the
reg vs output.
- confirm that it's not the load side of the -12 causing the
problem.
- pic(s) of the power supply board might help us identify the area
or get a better idea of what we're dealing with.
I took photos: https://goo.gl/photos/tRWV3ATTqx2R3eDz6
22 Nov
22 Nov
1:16 p.m.
I appreciate the guidance so far, thanks very much.
I found another power supply/motor driver board ("analog board") of the
same part number, hooked it up to the plotter and tested it. The -12v test
point on the new board read zero, and the other voltages were present just
like the original board.
I don't suppose that proves anything, but at least now I have 2 power
supplies.
I don't have an electronics background other than hobby-level tinkering. I
don't know how likely it is I'll be able to diagnose and fix this solely on
remote guidance, and in any case that seems like too much for me to ask.
If there is someone within driving distance of Seattle who could get this
thing working I will pay them what their time and effort is worth (I'm
trying to avoid shipping this monster or buying anyone plane tickets).
thanks
M.
On Fri, Nov 18, 2016 at 3:17 PM, Michael Newton <michael.newton at gmail.com>
wrote:
On Thu, Nov 17, 2016 at 12:10 AM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
It's linked from http://www.hpmuseum.net/collection_document.php - search
the page for "DraftMaster"
The document does appear to be missing the full schematic of the analog
board. I haven't been able to find them anywhere.
On 2016-Nov-16, at 11:34 PM, Michael Newton
wrote:
Yes -12v, sorry
That's right, there is a -5v test point that
reads zero.
From the previous discussion, presumably you mean -12V. Any
guidance? Like if I need to pull parts off and test them, which ones
might I go for? I'm a caveman with electronics.
Looking at:
7595-7596_HardwareSupportManual_07595-90025_168pages_Feb90.pdf
from hpmuseum.net via the link you supplied, the document seems to be
truncated.
The document simply ends part way through the schematics pages, and of
course the power supply schematic is missing.
(Aside, where did you find that document link? I didn't find it ref'd on
the hpmuseum pages.)
There is a minimal diagram for the power supply
on page 5-4 (pdf.30),
which shows the -12V supply as an independent (not part of the control
loop) secondary out of the switching supply. That's good as it limits the
likely problem region. There will be more components involved than shown
there, but the diode seen there on the -12V supply will lead to a filter
cap and possibly a 3-terminal linear regulator such as a 7912 or LM320-12,
or even a zener
regulator. There may be current limiting or overvoltage circuitry between
there and the actual -12 output of the supply.
- identify the -12V componentry in the power supply.
- if there is a 3-terminal -12V regulator check for input to the
reg vs output.
- confirm that it's not the load side of the -12 causing the
problem.
- pic(s) of the power supply board might help us identify the
area or get a better idea of what we're dealing with.
I took photos: https://goo.gl/photos/tRWV3ATTqx2R3eDz6
27 Nov
27 Nov
1:02 p.m.
(Getting back to this after a couple days..)
The board photos help although not detailed enough for certainty in tracing.
I see the power supply test points on the photos and on the diagram 12-14 (page 12-28) of
the manual.
Something to confirm: the -12V label is ambiguous in it's position on the board, do
you know for sure you measured the right spot for -12V?
It looks like it would be the nice solder button to the left of the minus sign but from
what I can discern it seems more likely to be the anode lead of the diode (CR2), right
above the "2" in the "-12V" label.
The diagram 12-14 indicates the test point as the cathode (banded lead) of CR2, this is
likely incorrect, if CR2 is the -12V rectifier the DC output would be the anode end. It
looks likes the draftsman just copied the pattern for the +15V diode.
As you suggest, detailed assistance from a distance may be difficult, but you might check
the above and see where things stand.
I'm not all that far away (Victoria area) but far enough to nonetheless be awkward for
transport or trip.
On 2016-Nov-22, at 1:16 PM, Michael Newton wrote:
I appreciate the guidance so far, thanks very much.
I found another power supply/motor driver board ("analog board") of the same
part number, hooked it up to the plotter and tested it. The -12v test point on the new
board read zero, and the other voltages were present just like the original board.
I don't suppose that proves anything, but at least now I have 2 power supplies.
I don't have an electronics background other than hobby-level tinkering. I don't
know how likely it is I'll be able to diagnose and fix this solely on remote guidance,
and in any case that seems like too much for me to ask.
If there is someone within driving distance of Seattle who could get this thing working I
will pay them what their time and effort is worth (I'm trying to avoid shipping this
monster or buying anyone plane tickets).
thanks
M.
On Fri, Nov 18, 2016 at 3:17 PM, Michael Newton <michael.newton at gmail.com>
wrote:
On Thu, Nov 17, 2016 at 12:10 AM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
On 2016-Nov-16, at 11:34 PM, Michael Newton wrote:
That's right, there is a -5v test point that
reads zero.
From the previous discussion, presumably you mean -12V.
Yes -12v, sorry
Any guidance? Like if I need to pull parts off
and test them, which ones
might I go for? I'm a caveman with electronics.
Looking at:
7595-7596_HardwareSupportManual_07595-90025_168pages_Feb90.pdf
from hpmuseum.net via the link you supplied, the document seems to be truncated.
The document simply ends part way through the schematics pages, and of course the power
supply schematic is missing.
(Aside, where did you find that document link? I didn't find it ref'd on the
hpmuseum pages.)
It's linked from http://www.hpmuseum.net/collection_document.php - search the page
for "DraftMaster"
The document does appear to be missing the full schematic of the analog board. I
haven't been able to find them anywhere.
There is a minimal diagram for the power supply on page 5-4 (pdf.30), which shows the
-12V supply as an independent (not part of the control loop) secondary out of the
switching supply. That's good as it limits the likely problem region. There will be
more components involved than shown there, but the diode seen there on the -12V supply
will lead to a filter cap and possibly a 3-terminal linear regulator such as a 7912 or
LM320-12, or even a zener
regulator. There may be current limiting or overvoltage circuitry between there and the
actual -12 output of the supply.
- identify the -12V componentry in the power supply.
- if there is a 3-terminal -12V regulator check for input to the reg vs output.
- confirm that it's not the load side of the -12 causing the problem.
- pic(s) of the power supply board might help us identify the area or get a
better idea of what we're dealing with.
I took photos: https://goo.gl/photos/tRWV3ATTqx2R3eDz6
30 Nov
30 Nov
5:48 p.m.
You were correct, I was looking for the -12v in the wrong place. I did find
-12v on the anode of CR2. So all voltages are correct at the test points.
So the LCD shows nothing and the device does not seem to respond to keypad
presses.
The other symptom is that I can hear some feeble and irregular clicky
noises from the paper drive motor. So it isn't purely just that the display
failed.
thanks
M.
On Sun, Nov 27, 2016 at 1:02 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
(Getting back to this after a couple days..)
The board photos help although not detailed enough for certainty in
tracing.
I see the power supply test points on the photos and on the diagram 12-14
(page 12-28) of the manual.
Something to confirm: the -12V label is ambiguous in it's position on the
board, do you know for sure you measured the right spot for -12V?
It looks like it would be the nice solder button to the left of the minus
sign but from what I can discern it seems more likely to be the anode lead
of the diode (CR2), right above the "2" in the "-12V" label.
The diagram 12-14 indicates the test point as the cathode (banded lead) of
CR2, this is likely incorrect, if CR2 is the -12V rectifier the DC output
would be the anode end. It looks likes the draftsman just copied the
pattern for the +15V diode.
As you suggest, detailed assistance from a distance may be difficult, but
you might check the above and see where things stand.
I'm not all that far away (Victoria area) but far enough to nonetheless be
awkward for transport or trip.
On 2016-Nov-22, at 1:16 PM, Michael Newton wrote:
truncated.
I appreciate the guidance so far, thanks very
much.
I found another power supply/motor driver board ("analog board") of the
same part number, hooked it up to the plotter and tested it. The -12v test
point on the new board read zero, and the other voltages were present just
like the original board.
I don't suppose that proves anything, but at least now I have 2 power
supplies.
I don't have an electronics background other than hobby-level tinkering.
I
don't know how likely it is I'll be able to diagnose and fix this solely
on remote guidance, and in any case that seems like too much for me to ask.
If there is someone within driving distance of Seattle who could get
this thing
working I will pay them what their time and effort is worth (I'm
trying to avoid shipping this monster or buying anyone plane tickets).
thanks
M.
On Fri, Nov 18, 2016 at 3:17 PM, Michael Newton <
michael.newton at
gmail.com> wrote:
On Thu, Nov 17, 2016 at 12:10 AM, Brent Hilpert
<hilpert at cs.ubc.ca>
wrote:
On 2016-Nov-16, at 11:34 PM, Michael Newton
wrote:
ones
That's right, there is a -5v test point that
reads zero.
From the previous discussion, presumably you mean -12V.
Yes -12v, sorry
> Any guidance? Like if I need to pull parts off and test them, which might I
go for? I'm a caveman with electronics.
Looking at:
7595-7596_HardwareSupportManual_07595-90025_168pages_Feb90.pdf
from hpmuseum.net via the link you supplied, the document seems to be The document simply ends part way through the
schematics pages, and of
course the power supply schematic is missing.
(Aside, where did you find that document link? I
didn't find it ref'd on
the hpmuseum pages.)
It's linked from http://www.hpmuseum.net/collection_document.php -
search the
page for "DraftMaster"
The document does appear to be missing the full schematic of the analog
board. I
haven't been able to find them anywhere.
There is a minimal diagram for the power supply on page 5-4 (pdf.30),
which shows
the -12V supply as an independent (not part of the control
loop) secondary out of the switching supply. That's good as it limits the
likely problem region. There will be more components involved than shown
there, but the diode seen there on the -12V supply will lead to a filter
cap and possibly a 3-terminal linear regulator such as a 7912 or LM320-12,
or even a zener
regulator. There may be current limiting or
overvoltage circuitry
between there and the actual -12 output of the supply.
- identify the -12V componentry in the power supply.
- if there is a 3-terminal -12V regulator check for input to the
reg vs
output.
- confirm that it's not the load side
of the -12 causing the
problem.
- pic(s) of the power supply board might
help us identify the
area or get a better idea of what we're dealing with.
I took photos: https://goo.gl/photos/tRWV3ATTqx2R3eDz6
6:06 p.m.
If you have an oscilloscope or logic analyser see if you have a clock signal at the main
CPU. If you do, see if your EPROMs are being accessed. If not you may have a clock issue,
a bad CPU or the CPU reset stuck low.
David Collins
(Sent from out of office)
On 1 Dec. 2016, at 12:48 pm, Michael Newton
<michael.newton at gmail.com> wrote:
You were correct, I was looking for the -12v in the wrong place. I did find
-12v on the anode of CR2. So all voltages are correct at the test points.
So the LCD shows nothing and the device does not seem to respond to keypad
presses.
The other symptom is that I can hear some feeble and irregular clicky
noises from the paper drive motor. So it isn't purely just that the display
failed.
thanks
M.
> On Sun, Nov 27, 2016 at 1:02 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
>
> (Getting back to this after a couple days..)
>
> The board photos help although not detailed enough for certainty in
> tracing.
> I see the power supply test points on the photos and on the diagram 12-14
> (page 12-28) of the manual.
>
> Something to confirm: the -12V label is ambiguous in it's position on the
> board, do you know for sure you measured the right spot for -12V?
> It looks like it would be the nice solder button to the left of the minus
> sign but from what I can discern it seems more likely to be the anode lead
> of the diode (CR2), right above the "2" in the "-12V" label.
> The diagram 12-14 indicates the test point as the cathode (banded lead) of
> CR2, this is likely incorrect, if CR2 is the -12V rectifier the DC output
> would be the anode end. It looks likes the draftsman just copied the
> pattern for the +15V diode.
>
> As you suggest, detailed assistance from a distance may be difficult, but
> you might check the above and see where things stand.
> I'm not all that far away (Victoria area) but far enough to nonetheless be
> awkward for transport or trip.
>
>
>> On 2016-Nov-22, at 1:16 PM, Michael Newton wrote:
>> I appreciate the guidance so far, thanks very much.
>>
>> I found another power supply/motor driver board ("analog board") of
the
> same part number, hooked it up to the plotter and tested it. The -12v test
> point on the new board read zero, and the other voltages were present just
> like the original board.
>>
>> I don't suppose that proves anything, but at least now I have 2 power
> supplies.
>>
>> I don't have an electronics background other than hobby-level tinkering.
> I don't know how likely it is I'll be able to diagnose and fix this solely
> on remote guidance, and in any case that seems like too much for me to ask.
>>
>> If there is someone within driving distance of Seattle who could get
> this thing working I will pay them what their time and effort is worth (I'm
> trying to avoid shipping this monster or buying anyone plane tickets).
>>
>> thanks
>> M.
>>
>>
>> On Fri, Nov 18, 2016 at 3:17 PM, Michael Newton <
> michael.newton at gmail.com> wrote:
>> On Thu, Nov 17, 2016 at 12:10 AM, Brent Hilpert <hilpert at cs.ubc.ca>
> wrote:
>>> On 2016-Nov-16, at 11:34 PM, Michael Newton wrote:
>>>
>>> That's right, there is a -5v test point that reads zero.
>>
>> From the previous discussion, presumably you mean -12V.
>>
>> Yes -12v, sorry
>>
>>> Any guidance? Like if I need to pull parts off and test them, which
> ones
>>> might I go for? I'm a caveman with electronics.
>>
>> Looking at:
>> 7595-7596_HardwareSupportManual_07595-90025_168pages_Feb90.pdf
>> from hpmuseum.net via the link you supplied, the document seems to be
> truncated.
>> The document simply ends part way through the schematics pages, and of
> course the power supply schematic is missing.
>> (Aside, where did you find that document link? I didn't find it ref'd on
> the hpmuseum pages.)
>>
>> It's linked from http://www.hpmuseum.net/collection_document.php -
> search the page for "DraftMaster"
>>
>> The document does appear to be missing the full schematic of the analog
> board. I haven't been able to find them anywhere.
>>
>> There is a minimal diagram for the power supply on page 5-4 (pdf.30),
> which shows the -12V supply as an independent (not part of the control
> loop) secondary out of the switching supply. That's good as it limits the
> likely problem region. There will be more components involved than shown
> there, but the diode seen there on the -12V supply will lead to a filter
> cap and possibly a 3-terminal linear regulator such as a 7912 or LM320-12,
> or even a zener
>> regulator. There may be current limiting or overvoltage circuitry
> between there and the actual -12 output of the supply.
>>
>> - identify the -12V componentry in the power supply.
>> - if there is a 3-terminal -12V regulator check for input to the
> reg vs output.
>> - confirm that it's not the load side of the -12 causing the
> problem.
>> - pic(s) of the power supply board might help us identify the
> area or get a better idea of what we're dealing with.
>>
>>
>> I took photos: https://goo.gl/photos/tRWV3ATTqx2R3eDz6
>
>
11:45 p.m.
If I power it up with the cover off, i can hear that several of the motors
are making unhealthy noises and not moving (although the pen carousel moves
very slightly before giving up and just howling). The paper drive motor and
also the little motor for the paper feed/takeup spindle are making the
weird noise and not turning.
Seems like the motors are being commanded to do the startup routine but are
acting weird. From what I remember of the brief period when this device
worked, when it's first powered up, it spins the pen carousel and checks
for pens, and also rapidly rolls the paper in and out a bit.
M.
On Wed, Nov 30, 2016 at 5:48 PM, Michael Newton <michael.newton at gmail.com>
wrote:
You were correct, I was looking for the -12v in the
wrong place. I did
find -12v on the anode of CR2. So all voltages are correct at the test
points.
So the LCD shows nothing and the device does not seem to respond to keypad
presses.
The other symptom is that I can hear some feeble and irregular clicky
noises from the paper drive motor. So it isn't purely just that the display
failed.
thanks
M.
On Sun, Nov 27, 2016 at 1:02 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
(Getting back to this after a couple days..)
The board photos help although not detailed enough for certainty in
tracing.
I see the power supply test points on the photos and on the diagram 12-14
(page 12-28) of the manual.
Something to confirm: the -12V label is ambiguous in it's position on the
board, do you know for sure you measured the right spot for -12V?
It looks like it would be the nice solder button to the left of the minus
sign but from what I can discern it seems more likely to be the anode lead
of the diode (CR2), right above the "2" in the "-12V" label.
The diagram 12-14 indicates the test point as the cathode (banded lead)
of CR2, this is likely incorrect, if CR2 is the -12V rectifier the DC
output would be the anode end. It looks likes the draftsman just copied the
pattern for the +15V diode.
As you suggest, detailed assistance from a distance may be difficult, but
you might check the above and see where things stand.
I'm not all that far away (Victoria area) but far enough to nonetheless
be awkward for transport or trip.
On 2016-Nov-22, at 1:16 PM, Michael Newton wrote:
truncated.
I appreciate the guidance so far, thanks very
much.
I found another power supply/motor driver board ("analog board") of the
same part number, hooked it up to the plotter and tested it. The -12v test
point on the new board read zero, and the other voltages were present just
like the original board.
I don't suppose that proves anything, but at least now I have 2 power
supplies.
I don't have an electronics background other than hobby-level
tinkering. I
don't know how likely it is I'll be able to diagnose and fix
this solely on remote guidance, and in any case that seems like too much
for me to ask.
If there is someone within driving distance of Seattle who could get
this thing
working I will pay them what their time and effort is worth (I'm
trying to avoid shipping this monster or buying anyone plane tickets).
thanks
M.
On Fri, Nov 18, 2016 at 3:17 PM, Michael Newton <
michael.newton at
gmail.com> wrote:
On Thu, Nov 17, 2016 at 12:10 AM, Brent Hilpert
<hilpert at cs.ubc.ca>
wrote:
On 2016-Nov-16, at 11:34 PM, Michael Newton
wrote:
ones
That's right, there is a -5v test point that
reads zero.
From the previous discussion, presumably you mean -12V.
Yes -12v, sorry
> Any guidance? Like if I need to pull parts off and test them, which might I
go for? I'm a caveman with electronics.
Looking at:
7595-7596_HardwareSupportManual_07595-90025_168pages_Feb90.pdf
from hpmuseum.net via the link you supplied, the document seems to be The document simply ends part way through the
schematics pages, and of
course the power supply schematic is missing.
(Aside, where did you find that document link? I
didn't find it ref'd
on the hpmuseum pages.)
It's linked from http://www.hpmuseum.net/collection_document.php -
search the
page for "DraftMaster"
The document does appear to be missing the full schematic of the analog
board. I
haven't been able to find them anywhere.
There is a minimal diagram for the power supply on page 5-4 (pdf.30),
which shows
the -12V supply as an independent (not part of the control
loop) secondary out of the switching supply. That's good as it limits the
likely problem region. There will be more components involved than shown
there, but the diode seen there on the -12V supply will lead to a filter
cap and possibly a 3-terminal linear regulator such as a 7912 or LM320-12,
or even a zener
regulator. There may be current limiting or
overvoltage circuitry
between there and the actual -12 output of the supply.
- identify the -12V componentry in the power supply.
- if there is a 3-terminal -12V regulator check for input to
the reg vs
output.
- confirm that it's not the load side
of the -12 causing the
problem.
- pic(s) of the power supply board might
help us identify the
area or get a better idea of what we're dealing with.
I took photos: https://goo.gl/photos/tRWV3ATTqx2R3eDz6
2712
days inactive
2732
days old
11 comments
5 participants
participants (5)
-
alexandre.tabajara＠gmail.com -
davidkcollins2＠gmail.com -
hilpert＠cs.ubc.ca -
michael.newton＠gmail.com -
pete＠petelancashire.com