HP LaserJet 4M -- Yipes! Black stripes!

[William Sommerwerck]

My LaserJet 4M has suddenly developed a serious problem -- just as I need it
to get out some important documents.

It's printing black lines across the width of the paper, about 1/8" to 1/4"
wide. They occur randomly (two to three per page) and look as if someone has
run a Magic Marker across the document.

In one case where the line ran through a graphic I use on my letterhead, the
line appeared to be "behind" the graphic -- that is, the white spaces in it
were reproduced with little degradation.

This does not appear to be a toner-cartridge problem. It seems more likely
to be intermittent laser output. (When the laser is off, the drum retains
its charge and picks up toner that's then transferred to the paper.)

I need this unit ASAP, and am willing to rip into it in the hopes that the
problem is a loose cable or failing solder joint. (I can download the
service manual for $7, if need be.)

Any ideas, anyone? Thanks in advance.

 

[PeterD]

My LaserJet 4M has suddenly developed a serious problem -- just as I need it
to get out some important documents.

It's printing black lines across the width of the paper, about 1/8" to 1/4"
wide. They occur randomly (two to three per page) and look as if someone has
run a Magic Marker across the document.

In one case where the line ran through a graphic I use on my letterhead, the
line appeared to be "behind" the graphic -- that is, the white spaces in it
were reproduced with little degradation.

This does not appear to be a toner-cartridge problem. It seems more likely
to be intermittent laser output. (When the laser is off, the drum retains
its charge and picks up toner that's then transferred to the paper.)

I need this unit ASAP, and am willing to rip into it in the hopes that the
problem is a loose cable or failing solder joint. (I can download the
service manual for $7, if need be.)

Any ideas, anyone? Thanks in advance.

First thing is to replace the cartridge. Saying "Doesn't appear to be"
won't hold much water in the real world... Sadly if you don't have a
spare cardridge you are going to have to gamble that it is bad, or
that you can fix the printer. Not (IMHO) a good gamble however.

Were this mine, I'd consider just replacing it, then find a used
cartridge to test with (see if someone can give you one that is on its
last legs...) to see if that is the problem.

Also, just for grins, clean carefully all the electircal connections
to the cartdridge.

 

[Tim Phipps]

Any ideas, anyone? Thanks in advance.

Suggest that you try the forums over on www.fixyourownprinter.com. I've
a couple of 4M and 4 Plus that I've kept running with info from that site.

 

[me]

My LaserJet 4M has suddenly developed a serious problem -- just as I
need it to get out some important documents.

It's printing black lines across the width of the paper, about 1/8" to
1/4" wide. They occur randomly (two to three per page) and look as if
someone has run a Magic Marker across the document.

In one case where the line ran through a graphic I use on my
letterhead, the line appeared to be "behind" the graphic -- that is,
the white spaces in it were reproduced with little degradation.

This does not appear to be a toner-cartridge problem. It seems more
likely to be intermittent laser output. (When the laser is off, the
drum retains its charge and picks up toner that's then transferred to
the paper.)

I need this unit ASAP, and am willing to rip into it in the hopes that
the problem is a loose cable or failing solder joint. (I can download
the service manual for $7, if need be.)

Any ideas, anyone? Thanks in advance.

From service manual;

Table 7-17 Random Horizontal Black Lines

Possible Cause Action

Laser/Scanning Assembly Replace the Laser/Scanner Assembly.
misaligned or damaged.

DC Controller PCA Replace the DC Controller PCA.

 

[William Sommerwerck]

William Sommerwerck wrote:

Suggest that you try the forums over on www.fixyourownprinter.com. I've
a couple of 4M and 4 Plus that I've kept running with info from that site.

I've already looked there, posted, and been given bad advice by a resident
expert. He misread my problem and assumed I was talking about vertical lines
along the edge. (I have that problem, too, but it's minor.)

Unfortunately, I know no one who owns one of these printers. I'll have to
call HP and some local repair shops tomorrow.

The odds are pretty good that the laser diode is failing.

This printer (made by Canon) is over 15 years old. It's a great product, and
I'd rather repair it than buy a new one.

 

[Tim Phipps]

I've already looked there, posted, and been given bad advice by a resident
expert. He misread my problem and assumed I was talking about vertical lines
along the edge. (I have that problem, too, but it's minor.)

Unfortunately, I know no one who owns one of these printers. I'll have to
call HP and some local repair shops tomorrow.

The odds are pretty good that the laser diode is failing.

This printer (made by Canon) is over 15 years old. It's a great product, and
I'd rather repair it than buy a new one.

In the UK at least you can pick up these printers on ebay fairly cheap
so possibly a good source of parts. As you are probably aware, the LJ 4
is the same as the 4M except for the postscript module.

 

[William Sommerwerck]

news:[email protected]:

From service manual;

Table 7-17 Random Horizontal Black Lines

Possible Cause Action

Laser/Scanning Assembly Replace the Laser/Scanner Assembly.
misaligned or damaged.

DC Controller PCA Replace the DC Controller PCA

Thanks for the confirmation of my intuitive analysis.

It's a simple fix -- but who knows what it will cost?

 

[William Sommerwerck]

In the UK at least you can pick up these printers on eBay fairly
cheap so possibly a good source of parts. As you are probably
aware, the 4 is the same as the 4M except for the PostScript
module.

I found several companies selling "refurbished" 4Ms for $200 or less --
shipping included. One wonders just how "refurbished" they are, or how long
they'll last.

I bought the 4M precisely because it supported PostScript, which was
critical for me. I would never own a printer that didn't support PostScript.
(It's nice to know that what comes out of a PostScript photosetter thousands
of miles away will exactly match what you printed out in your home office.)

It's funny how the 4M was touted as a Macintosh printer, when it works
perfectly well with Windows. (At the time the 4M came out, the Macintosh OS
natively supported PostScript.)

 

[Jamie]

Thanks for the confirmation of my intuitive analysis.

It's a simple fix -- but who knows what it will cost?

You want my 2 cents worth?
It's convenient how HP was able to print an exact fault that would
point to a component that's not intended for the basic user to correct
and local supplier to have..

This only tells me that some where along the line the flaw was found
and the instruction manual updated until the end of production of that
version..

Simply solution. Buy a new Laser printer of a different model.

 

[[email protected]]

I found several companies selling "refurbished" 4Ms for $200 or less --
shipping included. One wonders just how "refurbished" they are, or how long
they'll last.

I bought the 4M precisely because it supported PostScript, which was
critical for me. I would never own a printer that didn't support PostScript.
(It's nice to know that what comes out of a PostScript photosetter thousands
of miles away will exactly match what you printed out in your home office.)

It's funny how the 4M was touted as a Macintosh printer, when it works
perfectly well with Windows. (At the time the 4M came out, the Macintosh OS
natively supported PostScript.)

We have a LJ 4M (hand me down from billing) in engineering for the
occasional print job that had some paper feed problems. The repair
involved replacing all the rubber feed rollers. We also have a LJ 4MV
for printing 11x17 schematics and patch bay labels which was picked up
on eBay 3 years back 'refurbished' for $250 and it's going strong.

If you still use parallel port for the printer, you likely won't find
many (if any) of those.

GG

 

[Bob Urz]

Thanks for the confirmation of my intuitive analysis.

It's a simple fix -- but who knows what it will cost?

Well, what i would do is see if you get lucky. Take the unit apart. take
the toner cart out of it. take the boards out and blow them off outside
or carefully vacuum them inside. (you don't want toner dust all over).

THen carefully check connectors on the boards and check for cold solder
joints. I had a LJ2 that got funky and started working when i cleaned it
out and resoldered connections.

Bob

 

[William Sommerwerck]

You want my 2 cents worth? It's convenient how HP was able to
print an exact fault that would point to a component that's not
intended for the basic user to correct and local supplier to have.

This only tells me that some where along the line the flaw
was found and the instruction manual updated until the end
of production of that version..

Simple solution. Buy a new laser printer of a different model.

This is not a valid analysis of the situation.

Many years ago, Proctor-Silex introduced a series of "Lifetime"
appliances -- toaster, iron, coffee maker. They were highly modular. If the
heater base of the coffee maker failed, you simply bought a replacement.
That was that. No need to schlep the item to the repair shop.

These products didn't last long, because the guarantee that replacement
parts would be available indefinitely rendered it impractical for
Proctor-Silex to produce "new & improved" models.

The fact is that, other than the Proctor Lifetime appliances, and the
original Motorola Quasar, there have been few, if any, readily repairable
consumer products. It's much cheaper to assemble everything in such a way
that it becomes difficult to easily repair. * (The GE system of "value
analysis", adopted by Kodak and many other companies, further complicated
repairs by having one component perform multiple tasks.) As much as I would
like to be able to repair a broken item simply by replacing a standard
module, I realize that it isn't practical, either from an engineering or
market (economic) point of view.

A printer is not a coffee maker. Photographic and electronic devices contain
many components that are not, and never will be, readily user-replaceable.
And once any product becomes cheap enough to be a "commodity" item, you
simply toss it out rather than repairing it.

As for HP's analysis of product faults...

The description given, as was made clear, came from the service manual, not
the user manual. Furthermore, this specific problem will occur in virtually
_any_ laser printer where the laser or its drive circuitry deteriorates or
fails. It is predictable -- and was likely predicted -- before the first
_prototype_ of a laser printer was ever built! There was no "hidden flaw"
for HP to find. **

As for your knowledge of laser printers...

The early HP LaserJets are classic products. The 4M, though not as fast as
modern printers, is well-built and still produces beautiful output. Unless
it would cost too much to repair, I have no desire to replace it with
another model. That people still buy used 4 and 4M printers, and that OEM
toner cartridges are still available, says a great deal about them. (The
"engine" was a Canon product, by the way.)

* If circuit boards were "pluggable" and thereby "swappable", products would
become larger and more expensive, and would gain new connector-derived
failure modes.

** I used to own a Sony D-7S Discman. This model had a poorly designed laser
diode (from Sharp) that deteriorated prematurely. I had to literally
blackmail Sony to get them to fix it.

 

[msg]

I've already looked there, posted, and been given bad advice by a resident
expert. He misread my problem and assumed I was talking about vertical lines
along the edge. (I have that problem, too, but it's minor.)

Unfortunately, I know no one who owns one of these printers.

I'll bet many readers of this N.G. own one; my 4MP is the best printer on
my network at the moment. It is always wise to acquire contingency spares
(another LJ4) in advance; check thrift stores, back alleys in business
districts, dumpsters, electronics recyclers, etc. It should be possible
to maintain the machine for a long time to come.

Michael

 

[Meat Plow]

My LaserJet 4M has suddenly developed a serious problem -- just as I need it
to get out some important documents.

It's printing black lines across the width of the paper, about 1/8" to 1/4"
wide. They occur randomly (two to three per page) and look as if someone has
run a Magic Marker across the document.

In one case where the line ran through a graphic I use on my letterhead, the
line appeared to be "behind" the graphic -- that is, the white spaces in it
were reproduced with little degradation.

This does not appear to be a toner-cartridge problem. It seems more likely
to be intermittent laser output. (When the laser is off, the drum retains
its charge and picks up toner that's then transferred to the paper.)

I need this unit ASAP, and am willing to rip into it in the hopes that the
problem is a loose cable or failing solder joint. (I can download the
service manual for $7, if need be.)

Any ideas, anyone? Thanks in advance.

Pull the laser mech out and clean the mirror and the laser prism. If it
has a corona wire clean it. Replace the toner. Those three things usually
fixes her right up. I've had to do that on so many 4m's for industrial
customers back in the late 90's that i could do it in my sleep.

 

[William Sommerwerck]

Then carefully check connectors on the boards and check for cold
solder joints. I had a LJ2 that got funky and started working when
I cleaned it out and resoldered connections.

That's what I likely do, because I'm hoping that a bad solder joint will be
the problem. I'm not sure how to disasseble it, though. But I'll probably
attack it tomorrow.

 

[William Sommerwerck]

I'll bet many readers of this N.G. own one; my 4MP is the best
printer on my network at the moment. It's always wise to acquire
contingency spares in advance; check thrift stores, back alleys in
business districts, dumpsters, electronics recyclers, etc. It should
be possible to maintain the machine for a long time to come.

Agreed. I've already found at least one seemingly trustworth eBay seller.

Your point about contingency backups is well-taken. Last year I bought a
second JVC XP-A1000 hall synthesizer to cover me if my other one ever fails.

 

[William Sommerwerck]

Pull the laser mech out and clean the mirror and the laser prism.
If it has a corona wire clean it. Replace the toner. Those three
things usually fixes her right up. I've had to do that on so many
4Ms for industrial customers back in the late 90's that I could
do it in my sleep.

Thanks for the advice. (I've cleaned the corona wire several times.)

I know you can't "hold my hand", but I need just a bit of advice -- is it
fairly easy to rip 'er apart? The cabinet "hangs" on the guts; its not easy
to see where you should start dismembering.

I can buy a service manual on the Web for $7, so I won't be upset if you say
"Get the manual, ya lazy bum."

 

[Meat Plow]

Thanks for the advice. (I've cleaned the corona wire several times.)

I know you can't "hold my hand", but I need just a bit of advice -- is it
fairly easy to rip 'er apart? The cabinet "hangs" on the guts; its not easy
to see where you should start dismembering.

I can buy a service manual on the Web for $7, so I won't be upset if you say
"Get the manual, ya lazy bum."

The cabinet had hooks and latches. The kind where you push in on the
bottom or top of the seem to pull apart. And there are some screws that
although not exactly hidden, not easily spotted. My old 4m is at my office
packed away so if you can't figure it out and I can locate it I may be
able to walk you through the dis-assembly. If I recall correctly, one 4m
that suddenly had problems got that way from a user running an envelope
through it that had un-dried white-out on it. This partially blocked the
opening where the laser shines through. I think another had a piece of
label covering that opening. I think that opening is covered with glass.
I haven't worked on a 4m in a few years but used to work on quite a few as
they were pretty much the defacto business printer. They were work horses
too and could be equipped with a Jet Direct card.

 

[Meat Plow]

Thanks for the advice. (I've cleaned the corona wire several times.)

I know you can't "hold my hand", but I need just a bit of advice -- is it
fairly easy to rip 'er apart? The cabinet "hangs" on the guts; its not easy
to see where you should start dismembering.

I can buy a service manual on the Web for $7, so I won't be upset if you say
"Get the manual, ya lazy bum."

Ok here, just Googled this for you

http://wiki.freegeek.org/index.php/Repair_of_Laserjet_Printers

 

[James Sweet]

My LaserJet 4M has suddenly developed a serious problem -- just as I need
it
to get out some important documents.

It's printing black lines across the width of the paper, about 1/8" to
1/4"
wide. They occur randomly (two to three per page) and look as if someone
has
run a Magic Marker across the document.

In one case where the line ran through a graphic I use on my letterhead,
the
line appeared to be "behind" the graphic -- that is, the white spaces in
it
were reproduced with little degradation.

This does not appear to be a toner-cartridge problem. It seems more likely
to be intermittent laser output. (When the laser is off, the drum retains
its charge and picks up toner that's then transferred to the paper.)

I need this unit ASAP, and am willing to rip into it in the hopes that the
problem is a loose cable or failing solder joint. (I can download the
service manual for $7, if need be.)

Any ideas, anyone? Thanks in advance.

That's one I've never run into. Do the images look perfect? What if you
print out a page that is just an image, rather than something that sends
truetype fonts or postscript? If bitmaps print perfectly then the problem is
likely something on the main processing board.