2 Apr
2019
2 Apr
'19
3:56 p.m.
I rescued a LaserJet 4+ printer that I have been trying to restore.
Initially everything seemed ok and it seemed as if there may be just a bit
of an issue with paper pickup which I attributed to old paper in the tray.
However, soon I started getting the accordion paper jam which led me to
replacing all the rollers including the transfer roller. Now the paper flows
freely! However, I am having a new problem with printing. When I print, the
first 5-10 pages initially come out blank. The printer does not produce any
errors or error codes. The blank pages are warm (not hot though) as expected
out of a LJ.
After closer inspection it seems that the pages are printed SUPER light and
gradually get darker the more I use the printer continuously. Eventually the
printer starts printing continuous crisp black pages like new. This is a
whole page phenomenon (i.e. not gaps, missing areas, etc.).
A picture of the effect can be seen on VFC at:
www.vcfed.org/forum/attachment.php?attachmentid=52120&d=1554074105
Sorry for the poor quality picture.
Things I have checked/tried:
1. Using a brand new NOS toner (according to HP toner does not go bad as
long as it was sealed - which this was)
2. Swapping the new transfer roller for the old one - same problem, I have
to print out a bunch of pages until the printer starts acting normally.
3. I have checked the HV and an image is being transferred to the drum on
the toner cartridge.
4. A visual inspection of the fuser shows it to be ok.
Obviously this is happening printing demo pages so it has nothing to do with
computer, OS, SW, drivers, etc. Anybody run into this before? Any
ideas/suggestions. My Google fu turned up a bunch of discussions on the
laser door not being aligned correctly but that would seem to be a more
permanent issue i.e. unless you fixed the door no pages should print ever.
Mine gets better on its own after a number of pages are printed. Plus the
door and spring are fine - I checked them just in case.
I tried posting on FixYourOwnPrinter.com but for whatever reason the site
was not accepting the question. Any other forums you guys would recommend?
TIA!
-Ali
2 Apr
2 Apr
4:08 p.m.
If I'm not mistaken, high voltage capacitors on power supply. The corona
wire isn't charging the paper, so the image doesn't get transfered from the
cylinder to the paper to be pressed/fused in the fusor.
---8<---Corte aqui---8<---
http://www.tabajara-labs.blogspot.com
http://www.tabalabs.com.br
---8<---Corte aqui---8<---
Em ter, 2 de abr de 2019 ?s 16:56, Ali via cctalk <cctalk at classiccmp.org>
escreveu:
I rescued a LaserJet 4+ printer that I have been
trying to restore.
Initially everything seemed ok and it seemed as if there may be just a bit
of an issue with paper pickup which I attributed to old paper in the tray.
However, soon I started getting the accordion paper jam which led me to
replacing all the rollers including the transfer roller. Now the paper
flows
freely! However, I am having a new problem with printing. When I print, the
first 5-10 pages initially come out blank. The printer does not produce any
errors or error codes. The blank pages are warm (not hot though) as
expected
out of a LJ.
After closer inspection it seems that the pages are printed SUPER light and
gradually get darker the more I use the printer continuously. Eventually
the
printer starts printing continuous crisp black pages like new. This is a
whole page phenomenon (i.e. not gaps, missing areas, etc.).
A picture of the effect can be seen on VFC at:
www.vcfed.org/forum/attachment.php?attachmentid=52120&d=1554074105
Sorry for the poor quality picture.
Things I have checked/tried:
1. Using a brand new NOS toner (according to HP toner does not go bad as
long as it was sealed - which this was)
2. Swapping the new transfer roller for the old one - same problem, I have
to print out a bunch of pages until the printer starts acting normally.
3. I have checked the HV and an image is being transferred to the drum on
the toner cartridge.
4. A visual inspection of the fuser shows it to be ok.
Obviously this is happening printing demo pages so it has nothing to do
with
computer, OS, SW, drivers, etc. Anybody run into this before? Any
ideas/suggestions. My Google fu turned up a bunch of discussions on the
laser door not being aligned correctly but that would seem to be a more
permanent issue i.e. unless you fixed the door no pages should print ever.
Mine gets better on its own after a number of pages are printed. Plus the
door and spring are fine - I checked them just in case.
I tried posting on FixYourOwnPrinter.com but for whatever reason the site
was not accepting the question. Any other forums you guys would recommend?
TIA!
-Ali
4:47 p.m.
If I'm not mistaken, high voltage capacitors on
power supply. The corona wire isn't >charging the paper, so the image doesn't
get transferred from the cylinder to the paper to >be pressed/fused in the fusor.
Alexander,
Thanks for the reply. Grant also suggested the same thing. I am turning the printer upside
down as I write this to pull out the HV and see if anything looks bad from the get go.
Thanks!
-Ali
6:57 p.m.
Or the drum isn't getting charged in the first place, before light exposure then toner
dusting.
A way to check this: while the machine is in mid-copy, cut the power then open it up and
look at the drum.
Is there a toner image adhered to the drum section between where the surface is
image-exposed then dusted, and where it rolls against the paper?
Btw, if the fuser roller isn't heated enough, the symptom is that the paper comes out
with a normal image, except
the toner wipes off with finger swipe. Since it's just sitting on the paper not stuck
to it.
Old toner cartridges should be given a strong end-to-end shaking before being put into
use. Toner can settle in
lumps and block the path to the duster.
While you have the machine apart, always clean all the optical path lens surfaces. Dust
greatly reduces the print contrast. And because most machines use fan-blown air, dust gets
everywhere that isn't absolutely airtight sealed.
One other tip that might be useful. Very commonly with old photocopiers and laser printers
the rubber pick-up and paper feed rollers lose their 'tack' and slip on the paper.
I found that briefly soaking them in teatree oil restores the 'tack' quite well.
It soaks in and seems to have the right spread of rubber-soluble oils to keep the surface
a little tacky.
Anyone else found other solvent/oils with similar effect?
Guy
At 01:47 PM 2/04/2019 -0700, you wrote:
If I'm not
mistaken, high voltage capacitors on power supply. The corona wire isn't >charging
the paper, so the image doesn't get transferred from the cylinder to the paper to
>be pressed/fused in the fusor.
Alexander,
Thanks for the reply. Grant also suggested the same thing. I am turning the printer upside
down as I write this to pull out the HV and see if anything looks bad from the get go.
Thanks!
-Ali
8:28 p.m.
Hello Guy,
Or the drum isn't getting charged in the first
place, before light
exposure then toner dusting.
A way to check this: while the machine is in mid-copy, cut the power
then open it up and look at the drum.
Is there a toner image adhered to the drum section between where the
surface is image-exposed then dusted, and where it rolls against the
paper?
As I alluded to in my OP I did do this test. When I looked at the drum after
I start getting normal prints there is an image. However, at Grant's
suggestion I also looked at it when the printer was first turned on. At this
point there is very minimal toner adhering to the drum. As I print more and
more an appropriate amount of toner seems to adhere to the drum explaining
the improving picture. What I am trying to determine is now if this is a
problem with a component in the cartridge (drum, corona wire, etc.) or is it
with the HV supply board.
Btw, if the fuser roller isn't heated enough, the
symptom is that the
paper comes out with a normal image, except
the toner wipes off with finger swipe. Since it's just sitting on the
paper not stuck to it.
It is definitely not doing that. The toner is stuck on nice and tight - once
it eventually gets there.
Old toner cartridges should be given a strong end-to-end shaking before
being put into use. Toner can settle in
lumps and block the path to the duster.
I have done this multiple times. However, the problem reappears.
While you have the machine apart, always clean all the
optical path
lens surfaces. Dust greatly reduces the print contrast. And because
most machines use fan-blown air, dust gets everywhere that isn't
absolutely airtight sealed.
I have done that as well. However, given that the quality improves with
repeated printing and then falls back to none after 5 to 10 minutes of
cooling I don't think dust is an issue.
One other tip that might be useful. Very commonly with
old photocopiers
and laser printers the rubber pick-up and paper feed rollers lose their
'tack' and slip on the paper. I found that briefly soaking them in
teatree oil restores the 'tack' quite well. It soaks in and seems to
have the right spread of rubber-soluble oils to keep the surface a
little tacky.
Anyone else found other solvent/oils with similar effect?
I have never tried the oil/solvent trick. However, I did replace all the
rollers on this printer due to a paper jam issue so I don't think that is
the problem.
Thanks for the input and the suggestions.
-Ali
-Ali
9:13 p.m.
On 4/2/19 4:57 PM, Guy Dunphy via cctalk wrote:
One other tip that might be useful. Very commonly with
old photocopiers
and laser printers the rubber pick-up and paper feed rollers lose their
'tack' and slip on the paper. I found that briefly soaking them in
teatree oil restores the 'tack' quite well. It soaks in and seems to
have the right spread of rubber-soluble oils to keep the surface a
little tacky.
Anyone else found other solvent/oils with similar effect?
I've never considered oil / solvents. I'd worry about transference to
paper.
I have taken the rubber parts off and boiled them. Or at least put them
in water as hot as I could get it. (You can only do so much when you
put water in a blank CD spindle lid in the low wattage microwave at work.)
This helps remove the accumulated acid from the paper. In doing so, the
rubber becomes more tacky again.
I found one boil cycle to yield good results. Two cycles slightly
better. More than that and the RoI drops through the floor.
--
Grant. . . .
unix || die
4:09 p.m.
On 4/2/19 1:56 PM, Ali via cctalk wrote:
I rescued a LaserJet 4+ printer that I have been
trying to restore.
I miss my 4M+ with duplexer and extra paper tray. :-(
Initially everything seemed ok and it seemed as if
there may be just a bit
of an issue with paper pickup which I attributed to old paper in the tray.
I've found that the age of the paper isn't as important as any dust
accumulated on the top sheet.
However, soon I started getting the accordion paper
jam which led me to
replacing all the rollers including the transfer roller. Now the paper
flows freely!
Ya.
However, I am having a new problem with printing. When
I print, the
first 5-10 pages initially come out blank. The printer does not produce
any errors or error codes. The blank pages are warm (not hot though)
as expected out of a LJ.
I thought that there was a temperature sensor to detect how hot the
fuser is and error if it's not warm enough.
After closer inspection it seems that the pages are
printed
SUPER light and gradually get darker the more I use the printer
continuously. Eventually the printer starts printing continuous crisp
black pages like new. This is a whole page phenomenon (i.e. not gaps,
missing areas, etc.).
What?
I would question if there is an issue with the High Voltage and
transferring from the transfer roller to the paper. But you said you
checked the High Voltage. I thought the printer would detect this error
condition too.
A picture of the effect can be seen on VFC at:
www.vcfed.org/forum/attachment.php?attachmentid=52120&d=1554074105
Sorry for the poor quality picture.
I can't sign in to look at the picture. If I can, I'll look at it later.
Things I have checked/tried:
1. Using a brand new NOS toner (according to HP toner does not go bad
as long as it was sealed - which this was)
2. Swapping the new transfer roller for the old one - same problem, I have
to print out a bunch of pages until the printer starts acting normally.
3. I have checked the HV and an image is being transferred to the drum
on the toner cartridge.
How dark is the image that's being transferred to the drum?
If the normal image is being transferred and toner is being consumed, I
would wonder where the toner is going.
How clean / dirty is the fuser cleaning pad?
4. A visual inspection of the fuser shows it to be ok.
This doesn't sound like a fuser issue that I recall. Unless it's not
warm enough. (Again, the printer should detect this.)
Obviously this is happening printing demo pages so it
has nothing to do
with computer, OS, SW, drivers, etc.
Agreed.
Anybody run into this before? Any ideas/suggestions.
My Google fu turned
up a bunch of discussions on the laser door not being aligned correctly
but that would seem to be a more permanent issue i.e. unless you fixed
the door no pages should print ever.
Agreed.
Mine gets better on its own after a number of pages
are printed. Plus
the door and spring are fine - I checked them just in case.
So, it needs to be something that can change while the printer is operating.
The things that come to mind are shifting High Voltage (?) and temperature.
The other thing that comes to mind is possibly toner caked up in the
toner cartridge.
How long can you wait after getting a good printout before they start to
fade again? (Assuming the printer stays on.)
I tried posting on FixYourOwnPrinter.com but for
whatever reason the
site was not accepting the question. Any other forums you guys would
recommend? TIA!
I'll share your email with a friend who was a certified HP LaserJet
repairman. (I just pretended to be one a couple of jobs ago).
--
Grant. . . .
unix || die
4:26 p.m.
On 4/2/19 2:09 PM, Grant Taylor via cctalk wrote:
I'll share your email with a friend who was a
certified HP LaserJet
repairman.? (I just pretended to be one a couple of jobs ago).
My friend replied with the following:
"""
- Bad / dirty contacts to the hi voltage
- Bad high voltage
- Bad DC power supply.
"""
--
Grant. . . .
unix || die
6:20 p.m.
"""
- Bad / dirty contacts to the hi voltage
- Bad high voltage
- Bad DC power supply.
"""
Grant,
So I took out the HV board and it was super dirty (I added pictures on the thread in VCF
at
www.vcfed.org/forum/showthread.php?69109-Help-with-LJ-4-Printer-Repair-Plea…
).
Nothing that should really prevent electrical flow but I cleaned it out anyhow.
Re-installed and the issue remained.
While the printer was cold I ran another HV test and interestingly the toner drum had a
very faint picture on the drum. So it looks like the toner is not being deposited on the
drum appropriately until something "warms up". The question now is, is this a
toner problem (since I believe the corona wire is in the cartridge) or a HV problem. Since
I am not getting error codes I am guessing the cartridge is bad for one reason or
another.... How likely is that in your experience vs. the HV board going bad and just not
erroring out? Two of the caps look like they may have leaked on the HV board (see the
stains on the PCB in the before picture?). However, I don't see any bulging capacitors
or anything blown. Thanks.
-Ali
6:37 p.m.
On Tue, 2 Apr 2019, Ali via cctalk wrote:
While the printer was cold I ran another HV test and
interestingly the
toner drum had a very faint picture on the drum. So it looks like the
toner is not being deposited on the drum appropriately until something
"warms up". The question now is, is this a toner problem (since I
believe the corona wire is in the cartridge) or a HV problem. Since I am
not getting error codes I am guessing the cartridge is bad for one
reason or another.... How likely is that in your experience vs. the HV
board going bad and just not erroring out? Two of the caps look like
they may have leaked on the HV board (see the stains on the PCB in the
before picture?). However, I don't see any bulging capacitors or
anything blown. Thanks.
Since you are presumably going to keep this printer, once you fix it, or
at least use it for large jobs where wasting the first few pages isn't a
big issue, I would suggest getting another cartridge.
You will need it, eventually.
And, it provides a simple test to support or reject the in-the-crtridge
hypoothesis.
Trying another cartridge is almost always one of the first tests.
Those are sweet printers.
--
Grumpy Ol' Fred cisin at xenosoft.com
8:28 p.m.
Since you are presumably going to keep this printer,
once you fix it,
or
at least use it for large jobs where wasting the first few pages isn't
a
big issue, I would suggest getting another cartridge.
You will need it, eventually.
And, it provides a simple test to support or reject the in-the-crtridge
hypoothesis.
Trying another cartridge is almost always one of the first tests.
Fred,
I am considering it but as my only source for a cartridge seems to be eBay
it may not make much of a difference either way (in terms of having to wait
for it to arrive and wondering if that's any good.. :)). I am going to order
a cartridge anyhow and in the mean time I may just recap the board for good
measure. Since this is not my usual cup of tea ordering parts is a pain. I
am ordering one offs and then paying for S&H so the total cost is a pin
compared to some guys who just have supplies in bins around...
Those are sweet printers.
Yes they are. Currently all of my main printers are rescues: a Color LJ
5500HDN, LJ 2100, LS 4Si and this one which is actually going to a family
member once I can guarantee trouble free printing...
-Ali
--
Grumpy Ol' Fred cisin at xenosoft.com
9:39 p.m.
On 4/2/19 4:20 PM, Ali via cctalk wrote:
So I took out the HV board and it was super
dirty (I added pictures on the thread in VCF at
www.vcfed.org/forum/showthread.php?69109-Help-with-LJ-4-Printer-Repair-Plea…
).
I saw.
Nothing that should really prevent electrical flow but
I cleaned it out
anyhow. Re-installed and the issue remained.
ACK
While the printer was cold I ran another HV test and
interestingly the
toner drum had a very faint picture on the drum. So it looks like the
toner is not being deposited on the drum appropriately until something
"warms up".
My gut tells me that there's something going on with the HV section and
not actually pulling toner like it needs to.
Given your comment below about the caps, I'm wondering if they are
taking longer to charge up and the additional pages allow for them to
charge to a sufficient level.
The question now is, is this a toner problem (since I
believe the corona
wire is in the cartridge) or a HV problem. Since I am not getting error
codes I am guessing the cartridge is bad for one reason or another.... How
likely is that in your experience vs. the HV board going bad and just
not erroring out? Two of the caps look like they may have leaked on the
HV board (see the stains on the PCB in the before picture?). However,
I don't see any bulging capacitors or anything blown. Thanks.
It sounds like the caps have not (yet) completely failed.
I'd bet $10 on the HV supply being your problem.
--
Grant. . . .
unix || die
9 Apr
9 Apr
11:23 p.m.
It sounds like the caps have not (yet) completely failed.
I'd bet $10 on the HV supply being your problem.
And you would be $10 richer now :D
I just replaced the caps on the HV board ($5 worth of parts $7.99 for S&H :facepalm:)
and it fired right up and started printing. None of the caps looked "bad". I
don't have an ESR meter but when I tested the caps w/ my multimeter (outside of the
circuit of course) only one seemed bad to my very rudimentary understanding. It was the
big 25V 470uF cap. It never reached a resistance of infinity (which I believe a good cap
will do). Not sure if this is a true indication of a bad cap or that my MM just
couldn't charge the cap sufficiently. In either case it is now replaced w/ a 25V 470uF
125C Panasonic part.
Thanks to everyone for the help.
-Ali
10 Apr
10 Apr
12:31 a.m.
On 4/9/19 9:23 PM, Ali via cctalk wrote:
And you would be $10 richer now :D
I just replaced the caps on the HV board ($5 worth of parts $7.99 for S&H
:facepalm:) and it fired right up and started printing. None of the caps
looked "bad". I don't have an ESR meter but when I tested the caps w/
my multimeter (outside of the circuit of course) only one seemed bad to
my very rudimentary understanding. It was the big 25V 470uF cap. It never
reached a resistance of infinity (which I believe a good cap will do).
Not sure if this is a true indication of a bad cap or that my MM just
couldn't charge the cap sufficiently. In either case it is now replaced w/
a 25V 470uF 125C Panasonic part.
Thanks to everyone for the help.
Cool!
I'm glad that you got it working. :-)
--
Grant. . . .
unix || die
2 Apr
2 Apr
4:47 p.m.
Grant,
I miss my 4M+ with duplexer and extra paper tray. :-(
Yes, these guys were built like tanks. This one acts as a 4M now because I added the PS
module to it and it has local talk support. No duplexer or extra paper tray though :(.
I've found that the age of the paper isn't as
important as any dust
accumulated on the top sheet.
I will have to keep that in mind. This paper was old - not sure how old but it was in the
tray when I found the printer on the side of the road. So better to recycle it then risk
it I think.
I thought that there was a temperature sensor to
detect how hot the
fuser is and error if it's not warm enough.
It may be "hot enough". They are certainly warm. And I don't detect them
getting any hotter to touch as more printing goes on so this part could all be in my
head.
I can't sign in to look at the picture. If I can,
I'll look at it
later.
I can post it elsewhere if needed. It basically shows the picture getting darker with
subsequent printings.
How dark is the image that's being transferred to
the drum?
I am not sure how to quantify it but it looks solid on the drum. I will
have to repeat the test with a "cool" printer and see if it still looks solid or
not.
If the normal image is being transferred and toner is
being consumed, I
would wonder where the toner is going.
Never thought about it but the extra toner (I assume not all the toner is being
transferred to every page of print) must get swept up back in to the cartridge somewhere,
no?
How clean / dirty is the fuser cleaning pad?
Not too bad. It is worth mentioning that the printer doesn't seem abused in its old
life either. Only 65K of prints...
The things that come to mind are shifting High Voltage
(?) and
temperature.
Both of which should produce an error usually...
The other thing that comes to mind is possibly toner caked up in the
toner cartridge.
I thought about bad toner but that doesn't explain the improvement with time/prints.
Or why it would go bad again after cooling down.
How long can you wait after getting a good printout before they start
to
fade again? (Assuming the printer stays on.)
I would say 5 - 10 minutes. Once I get good quality prints the subsequent pages all look
great...
I'll share your email with a friend who was a
certified HP LaserJet
repairman. (I just pretended to be one a couple of jobs ago).
...
My friend replied with the following:
"""
- Bad / dirty contacts to the hi voltage
- Bad high voltage
- Bad DC power supply.
--
Thanks that was quick! I am pulling out the HV portion now to take a look. If I understand
correct the DC (LV) supplies everything else except the engine. Those all seem to be
working fine. Cleaning contacts is easy (and cheap) so that will be my first fix unless I
see something glaringly obvious with the caps on the HV.
Thank you.
-Ali
9:36 p.m.
On 4/2/19 2:47 PM, Ali via cctalk wrote:
Yes, these guys were built like tanks. This one acts
as a 4M now because
I added the PS module to it and it has local talk support. No duplexer
or extra paper tray though :(.
It was really a 4+. I picked it up for $1 ~ $10 at a ham fest. I then
maxed the memory and added PostScript, thus turning it into a 4M+.
The duplexer was interesting. It interfaced with the back of the
printer in place of the fold down back cover. The extra paper tray was
part of the duplexer and where the paper flipped around. - I think it
went under the tray instead of out the top, then came back up and feed
like the normal expansion tray.
I will have to keep that in mind. This paper was old -
not sure how
old but it was in the tray when I found the printer on the side of the
road. So better to recycle it then risk it I think.
I'd be more worried about moisture with the paper. But, sure, recycle
it and replace it.
It may be "hot enough". They are certainly
warm. And I don't detect them
getting any hotter to touch as more printing goes on so this part could
all be in my head.
I don't remember the 4[M][+] ever getting all that warm.
The 4Si, that would get really warm. Especially if you were using the
job jogger, duplexing, and printing reams at a time.
I can post it elsewhere if needed. It basically shows
the picture getting
darker with subsequent printings.
I created an account, got logged in, and see both pictures.
I don't see any typical roller related defects.
I am not sure how to quantify it but it looks solid on
the drum. I will
have to repeat the test with a "cool" printer and see if it still looks
solid or not.
ACK
Never thought about it but the extra toner (I assume
not all the toner
is being transferred to every page of print) must get swept up back in
to the cartridge somewhere, no?
I am guessing that you have an HV issue, and the toner is not coming out
of the cartridge.
Not too bad. It is worth mentioning that the printer
doesn't seem abused
in its old life either. Only 65K of prints...
It's a younging.
Both of which should produce an error usually...
I thought so. However, Dave M. indicates that HV problems /won't/
produce an error.
I thought about bad toner but that doesn't explain
the improvement with
time/prints. Or why it would go bad again after cooling down.
That doesn't sound like a toner cartridge issue to me.
I would say 5 - 10 minutes. Once I get good quality
prints the subsequent
pages all look great...
That tells me that it's not something mechanical. I say that because it
would be all the time. (I guess a cold solder joint could be
mechanical. But I think that would present differently.)
Thanks that was quick! I am pulling out the HV portion
now to take a
look. If I understand correct the DC (LV) supplies everything else except
the engine. Those all seem to be working fine. Cleaning contacts is easy
(and cheap) so that will be my first fix unless I see something glaringly
obvious with the caps on the HV.
Yep. He's retired.
Thank you.
You're welcome.
--
Grant. . . .
unix || die
8:38 p.m.
Ali via cctalk wrote on 4/2/2019 3:56 PM:
I rescued a LaserJet 4+ printer that I have been
trying to restore.
Initially everything seemed ok and it seemed as if there may be just a bit
of an issue with paper pickup which I attributed to old paper in the tray.
However, soon I started getting the accordion paper jam which led me to
replacing all the rollers including the transfer roller. Now the paper flows
freely! However, I am having a new problem with printing. When I print, the
first 5-10 pages initially come out blank. The printer does not produce any
errors or error codes. The blank pages are warm (not hot though) as expected
out of a LJ.
After closer inspection it seems that the pages are printed SUPER light and
gradually get darker the more I use the printer continuously. Eventually the
printer starts printing continuous crisp black pages like new. This is a
whole page phenomenon (i.e. not gaps, missing areas, etc.).
A picture of the effect can be seen on VFC at:
www.vcfed.org/forum/attachment.php?attachmentid=52120&d=1554074105
Sorry for the poor quality picture.
Things I have checked/tried:
1. Using a brand new NOS toner (according to HP toner does not go bad as
long as it was sealed - which this was)
2. Swapping the new transfer roller for the old one - same problem, I have
to print out a bunch of pages until the printer starts acting normally.
3. I have checked the HV and an image is being transferred to the drum on
the toner cartridge.
4. A visual inspection of the fuser shows it to be ok.
Obviously this is happening printing demo pages so it has nothing to do with
computer, OS, SW, drivers, etc. Anybody run into this before? Any
ideas/suggestions. My Google fu turned up a bunch of discussions on the
laser door not being aligned correctly but that would seem to be a more
permanent issue i.e. unless you fixed the door no pages should print ever.
Mine gets better on its own after a number of pages are printed. Plus the
door and spring are fine - I checked them just in case.
I tried posting on FixYourOwnPrinter.com but for whatever reason the site
was not accepting the question. Any other forums you guys would recommend?
TIA!
-Ali
Just my little bit of input on this...the high voltage power supply is
just about the only thing that there is no error code for.? I had one
fail and the printer didn't flag any errors.? Changing the HV supply
fixed it.
It sounds to me like your problem is related to the high voltage supply.
Dave
8:42 p.m.
You could well have a temp sensitive HV supply or excess moisture in it that keeps the HT
low until the warmth of operation dries it out. Given the problem returns each time, a
temp sensitive HV sounds likely.
Not sure how quickly you could remove and replace the supply but you might trying using
freeze spray on the supply when the problem occurs and see if that fixes it temporarily.
David Collins
+61 424 785 131
On 3 Apr 2019, at 11:38 am, Dave Mabry via cctalk
<cctalk at classiccmp.org> wrote:
Ali via cctalk wrote on 4/2/2019 3:56 PM:
I rescued a LaserJet 4+ printer that I have been
trying to restore.
Initially everything seemed ok and it seemed as if there may be just a bit
of an issue with paper pickup which I attributed to old paper in the tray.
However, soon I started getting the accordion paper jam which led me to
replacing all the rollers including the transfer roller. Now the paper flows
freely! However, I am having a new problem with printing. When I print, the
first 5-10 pages initially come out blank. The printer does not produce any
errors or error codes. The blank pages are warm (not hot though) as expected
out of a LJ.
After closer inspection it seems that the pages are printed SUPER light and
gradually get darker the more I use the printer continuously. Eventually the
printer starts printing continuous crisp black pages like new. This is a
whole page phenomenon (i.e. not gaps, missing areas, etc.).
A picture of the effect can be seen on VFC at:
www.vcfed.org/forum/attachment.php?attachmentid=52120&d=1554074105
Sorry for the poor quality picture.
Things I have checked/tried:
1. Using a brand new NOS toner (according to HP toner does not go bad as
long as it was sealed - which this was)
2. Swapping the new transfer roller for the old one - same problem, I have
to print out a bunch of pages until the printer starts acting normally.
3. I have checked the HV and an image is being transferred to the drum on
the toner cartridge.
4. A visual inspection of the fuser shows it to be ok.
Obviously this is happening printing demo pages so it has nothing to do with
computer, OS, SW, drivers, etc. Anybody run into this before? Any
ideas/suggestions. My Google fu turned up a bunch of discussions on the
laser door not being aligned correctly but that would seem to be a more
permanent issue i.e. unless you fixed the door no pages should print ever.
Mine gets better on its own after a number of pages are printed. Plus the
door and spring are fine - I checked them just in case.
I tried posting on FixYourOwnPrinter.com but for whatever reason the site
was not accepting the question. Any other forums you guys would recommend?
TIA!
-Ali
Just my little bit of input on this...the high voltage power supply is just about the
only thing that there is no error code for. I had one fail and the printer didn't
flag any errors. Changing the HV supply fixed it.
It sounds to me like your problem is related to the high voltage supply.
Dave
3 Apr
3 Apr
4:24 a.m.
Just my little bit of input on this...the high voltage
power supply is
just about the only thing that there is no error code for. I had one
fail and the printer didn't flag any errors. Changing the HV supply
fixed it.
It sounds to me like your problem is related to the high voltage
supply.
Dave
Hi Dave,
Thanks for that tidbit. I didn't realize that a HV failure would not produce any error
codes. If that is the case looks like I am recapping a board. Out of curiosity what
symptoms were you getting? Thanks.
-Ali
11:41 a.m.
On 04/03/2019 03:24 AM, Ali via cctalk wrote:
Thanks for that tidbit. I didn't realize that a HV
failure
would not produce any error codes. If that is the case
looks like I am recapping a board. Out of curiosity what
symptoms were you getting?
Nope, I think there is some sort of self-check on the fuser
thermistors, but the corona supply is open-loop on most
printers. There is also a self-check on the laser, as the
beam has to hit a sensor to start the timing of the pixels.
So a failed laser or polygon motor will cause an error.
Good luck with it!
Jon
2 Apr
2 Apr
9:48 p.m.
On 04/02/2019 02:56 PM, Ali via cctalk wrote:
I rescued a LaserJet 4+ printer that I have been
trying to restore.
Initially everything seemed ok and it seemed as if there may be just a bit
of an issue with paper pickup which I attributed to old paper in the tray.
However, soon I started getting the accordion paper jam which led me to
replacing all the rollers including the transfer roller. Now the paper flows
freely! However, I am having a new problem with printing. When I print, the
first 5-10 pages initially come out blank. The printer does not produce any
errors or error codes. The blank pages are warm (not hot though) as expected
out of a LJ.
After closer inspection it seems that the pages are printed SUPER light and
gradually get darker the more I use the printer continuously. Eventually the
printer starts printing continuous crisp black pages like new. This is a
whole page phenomenon (i.e. not gaps, missing areas, etc.).
Is the fuser roller warming up properly? Or, is it the
corona supply is having trouble coming up to voltage? You
should pull the bottom of the printer apart and thoroughly
clean the PC board on both sides. If you have never done
this, it will be a HUGE BLACK MESS with spilled toner dust -
don't ask how I know this!
I have a 5M, but I think the mechanism is the same.
Jon
3 Apr
3 Apr
4:24 a.m.
Is the fuser roller warming up properly? Or, is it
the
corona supply is having trouble coming up to voltage? You
should pull the bottom of the printer apart and thoroughly
clean the PC board on both sides. If you have never done
this, it will be a HUGE BLACK MESS with spilled toner dust -
don't ask how I know this!
Jon,
Based on the info coming through on the list a "cold" fuser would produce
toner that would wipe off/flake off of the printed sheet. This is not
happening in my case so I am guessing the fuser is getting hot "enough". The
current hive thinking seems to be toward the corona wire - specifically
failing caps in HV needing time to warm up to specs before working properly.
-Ali
11:44 a.m.
On 04/03/2019 03:24 AM, Ali via cctalk wrote:
OK, sounds right.
Is the fuser
roller warming up properly? Or, is it the
corona supply is having trouble coming up to voltage? You
should pull the bottom of the printer apart and thoroughly
clean the PC board on both sides. If you have never done
this, it will be a HUGE BLACK MESS with spilled toner dust -
don't ask how I know this!
Jon,
Based on the info coming through on the list a "cold" fuser would produce
toner that would wipe off/flake off of the printed sheet. This is not
happening in my case so I am guessing the fuser is getting hot "enough".
The
current hive thinking seems to be toward the corona wire - specifically
failing caps in HV needing time to warm up to specs before working properly.
First, since you have not checked with another cartridge, is
to examine the corona wires and/or "combs" on the cart.
Sometimes the wires break at one end. Also, toner spills
could short it out, I've had that before. Bent contacts on
the cart where it connects the HV to the printer could also
be making bad/no contact.
But, the caps could be it, the symptom where it starts
working after warming up does indicate weak caps.
Jon
4:41 p.m.
On 4/3/2019 9:44 AM, Jon Elson via cctalk wrote:
First, since you have not checked with another
cartridge, is to examine
the corona wires and/or "combs" on the cart. Sometimes the wires break
at one end.? Also, toner spills could short it out, I've had that
before.? Bent contacts on the cart where it connects the HV to the
printer could also be making bad/no contact.
But, the caps could be it, the symptom where it starts working after
warming up does indicate weak caps.
You might want to order a few HV diodes because a leaky HV diode
could be found if the caps are good.
Jon
11:48 a.m.
If I were you, I'd buy a complete DC/hv assembly, it must be cheap on ebay
---8<---Corte aqui---8<---
http://www.tabajara-labs.blogspot.com
http://www.tabalabs.com.br
---8<---Corte aqui---8<---
Em qui, 4 de abr de 2019 ?s 12:39, Ali via cctalk <cctalk at classiccmp.org>
escreveu:
You might want to order a few HV diodes because a
leaky HV diode
could be found if the caps are good.
Thanks. I will keep that in mind.
-Ali
12:10 p.m.
If I were you, I'd buy a complete DC/hv assembly,
it must be cheap on ebay
Where is the fun in that? :) To be honest I checked and it is about $50. Parts from mouser
(w/ upgrades to 105c caps) are about $5 plus S&H. I will try recapping and if that
fails then I will consider buying a whole HV board.
1934
days inactive
1942
days old
27 comments
9 participants
participants (9)
-
alexandre.tabajara＠gmail.com -
bfranchuk＠jetnet.ab.ca -
cctalk＠gtaylor.tnetconsulting.net -
cctalk＠ibm51xx.net -
cisin＠xenosoft.com -
davidkcollins2＠gmail.com -
dmabry＠mich.com -
elson＠pico-systems.com -
guykd＠optusnet.com.au