I got some good help here last time to fix a paper jamming problem with the
lower drawer in my HP LaserJet 4000. It was the sticky solenoid issue in the
main paper tray. Now I have a different issue with the way the paper doesn't
feed from the manual (upper) tray. The pick up roller starts to move just a
small amount, then it stops. If I don't intervene, I get a paper feed error.
If I do intervene and give the roller a push, it will get the paper loaded.
Then there's a pause, and I see it try to move again. Then I have to push it
again. Then all goes well. Is this the other upper solenoid? I cleaned them
both last time I had it apart. I thought a sticky solenoid causes the
opposite problem where the paper won't stop loading. It used to be
intermittent but now it happens all the time.

Thanks for your reply.
--
David Farber
Los Osos, CA

On Tue, 7 Oct 2014 13:50:46 -0700, "David Farber"
wrote:

I got some good help here last time to fix a paper jamming problem with the
lower drawer in my HP LaserJet 4000. It was the sticky solenoid issue in the
main paper tray.

Yep. Common problem. I think that there is (not sure) also a
solenoid INSIDE the paper tray frame that can also cause paper feed
jams. I couldn't tell for sure from the exploded views:
http://www.printerworks.com/Catalogs/4K-Catalog/4K-AssblyContents.html#Parts

Mo
http://blog.marketpoint.com/2011/03/07/common-error-codes-and-problems-with-the-hp-laserjet-4000-4050-4100/

Now I have a different issue with the way the paper doesn't
feed from the manual (upper) tray. The pick up roller starts to move just a
small amount, then it stops. If I don't intervene, I get a paper feed error.
If I do intervene and give the roller a push, it will get the paper loaded.
Then there's a pause, and I see it try to move again. Then I have to push it
again. Then all goes well. Is this the other upper solenoid?

Sure sounds like a solenoid problem. The feed roller is not locked in
the correct position on the first attempt. It then rotates around
maybe 300 degrees, gets to where it should be, and starts to push
normally. However, it doesn't finish going around a second time, and
just stops.

I cleaned them
both last time I had it apart. I thought a sticky solenoid causes the
opposite problem where the paper won't stop loading. It used to be
intermittent but now it happens all the time.

It might also be how thick the felt you attached to the solenoid
armature. If too thin, the armature will stick to the magnetized coil
core. If too thick, the armature pawl will rub against the cam, and
possibly stick.

Offhand, I would guess(tm) that it's the feed roller and it's
accomplice the separation pad. Just buy a kit on eBay and replace
everything. For example:
http://www.ebay.com/itm/271623116889

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
On Tue, 7 Oct 2014 13:50:46 -0700, "David Farber"
wrote:

I got some good help here last time to fix a paper jamming problem
with the lower drawer in my HP LaserJet 4000. It was the sticky
solenoid issue in the main paper tray.

Yep. Common problem. I think that there is (not sure) also a
solenoid INSIDE the paper tray frame that can also cause paper feed
jams. I couldn't tell for sure from the exploded views:
http://www.printerworks.com/Catalogs/4K-Catalog/4K-AssblyContents.html#Parts

Mo
http://blog.marketpoint.com/2011/03/07/common-error-codes-and-problems-with-the-hp-laserjet-4000-4050-4100/

Now I have a different issue with the way the paper doesn't
feed from the manual (upper) tray. The pick up roller starts to move
just a small amount, then it stops. If I don't intervene, I get a
paper feed error. If I do intervene and give the roller a push, it
will get the paper loaded. Then there's a pause, and I see it try to
move again. Then I have to push it again. Then all goes well. Is
this the other upper solenoid?

Sure sounds like a solenoid problem. The feed roller is not locked in
the correct position on the first attempt. It then rotates around
maybe 300 degrees, gets to where it should be, and starts to push
normally. However, it doesn't finish going around a second time, and
just stops.

I cleaned them
both last time I had it apart. I thought a sticky solenoid causes the
opposite problem where the paper won't stop loading. It used to be
intermittent but now it happens all the time.

It might also be how thick the felt you attached to the solenoid
armature. If too thin, the armature will stick to the magnetized coil
core. If too thick, the armature pawl will rub against the cam, and
possibly stick.

Offhand, I would guess(tm) that it's the feed roller and it's
accomplice the separation pad. Just buy a kit on eBay and replace
everything. For example:
http://www.ebay.com/itm/271623116889

Hi Jeff,

I removed the tray assembly 1 (that's the manual feed unit) and looked for
any irregularities. I couldn't find any. The solenoid was not sticking. The
felt I put on from a few months ago was attached and still looked new. I was
trying to follow the drive train sequence that ends up turning the manual
feed pickup roller but it wasn't so easy. I didn't feel like tearing down
the entire chassis. So I put it back together and for now, it's working
again. It would seem to me that it couldn't be a roller problem if the
mechanism stalls out and giving the pickup roller a little push gets it
going again. The page count is over 40,000 now. I wonder how many new
printers last that long.

Thanks for your reply.
--
David Farber
Los Osos, CA

On Sun, 12 Oct 2014 10:53:21 -0700, "David Farber"
wrote:

I removed the tray assembly 1 (that's the manual feed unit) and looked for
any irregularities.

I was referring to Tray 2. Unscrew the well hidden screws holding the
Tray 2 assembly to the printer, and the tray and the tray mechanism
should fall off. Take it apart and I think you'll find yet another
solenoid. I'm not sure and have no easy way to check right now.

So I put it back together and for now, it's working
again.

I hate it when that happens. It should fail again just when you need
the printer most.

It would seem to me that it couldn't be a roller problem if the
mechanism stalls out and giving the pickup roller a little push gets it
going again.

I beg to differ. The timing of the paper feed is controlled by the
solenoid you fixed. Mangle the timing in any manner, and it will act
something like what you've described.

The page count is over 40,000 now. I wonder how many new
printers last that long.

On the 4000/4050/4100 series, I have so replace the rubber parts, some
gears, and rebuild the fuser at about 50,000 pages. Much depends on
the environment. In a really clean office, I can sometimes go to
about 75,000 before anything needs replacing. At a local auto shop,
I'm lucky if anything prints 10,000 pages before something goes awry.
The worst was a machine shop, where everything was coated with a
mixture of metallic dust and lubricant, which operates like an
abrasive. I have 4200/4250/4300/4350 printers in tax preparation
offices that show well over 150,000 pages. The trick here is that I
do a pre-emptive cleaning and roller replacement every year before tax
season. That's about $25 in parts, $75 in labor per printer. After I
started doing that, I've had no after midnight phone calls from the
tax customers demanding I run over and fix their overloaded printer.
The most I've seen on a printer was a LJ4+ with over 250,000 pages. It
didn't die from overuse, but rather fell apart when someone dropped it
during an office reorganization.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

The page count is over 40,000 now. I wonder how many new
printers last that long.

Surely this is a typo. Did you mean 400,000?
400k on a 4000/4050 is no big deal for a machine
in daily & heavy use. On an EX-engine (4,4+,5)
this is just getting broke in.

For your Tray 1 problem you need a RG5-2651 clutch.
They're $29 at Printerworks.com

--- news://freenews.netfront.net/ - complaints: ---

David K. Bryant wrote:
The page count is over 40,000 now. I wonder how many new
printers last that long.

Surely this is a typo. Did you mean 400,000?
400k on a 4000/4050 is no big deal for a machine
in daily & heavy use. On an EX-engine (4,4+,5)
this is just getting broke in.

For your Tray 1 problem you need a RG5-2651 clutch.
They're $29 at Printerworks.com

--- news://freenews.netfront.net/ - complaints: ---

Hi David,

No, 40k is correct. It gets light use now. I acquired it used about 7 years
ago.

Regarding the clutch which I found at
http://www.printerworks.com/Catalogs...PaperFeed.html I was
wondering, is there one particular part in that assembly which causes the
failure?

Thanks for your reply.
--
David Farber
Los Osos, CA

I was
wondering, is there one particular part in that assembly which causes the
failure?


The electromagnetic clutch on the end of the shaft.
Failure modes:

not engaging
always engaged
slipping

Usually the latter. This is evident when the
paper feeds but not all the way thru. Paper Jam
error message often means that the paper failed
to reach a sensor at the right time.


--- news://freenews.netfront.net/ - complaints: ---

David K. Bryant wrote:
I was
wondering, is there one particular part in that assembly which
causes the failure?


The electromagnetic clutch on the end of the shaft.
Failure modes:

not engaging
always engaged
slipping

Usually the latter. This is evident when the
paper feeds but not all the way thru. Paper Jam
error message often means that the paper failed
to reach a sensor at the right time.


--- news://freenews.netfront.net/ - complaints: ---

Is the clutch serviceable or is not worth the effort?

Thanks for your reply.
--
David Farber
Los Osos, CA

On 12/08/2014 10:02 AM, David Farber wrote:
David K. Bryant wrote:
The electromagnetic clutch on the end of the shaft.

Is the clutch serviceable or is not worth the effort?

Certainly not worth the effort and
possibly not even serviceable.

--- news://freenews.netfront.net/ - complaints: ---

"David K. Bryant" wrote in message
...
On 12/08/2014 10:02 AM, David Farber wrote:
David K. Bryant wrote:
The electromagnetic clutch on the end of the shaft.

Is the clutch serviceable or is not worth the effort?

Certainly not worth the effort and
possibly not even serviceable.

--- news://freenews.netfront.net/ - complaints: ---

Hi David,

I finally disassembled the printer again to look at the electromagnetic
clutch and the related components. I put DC on the clutch terminals and
manually turned the gear that the engine normally turns. I could feel the
magnetic field pushing on the opposite end but the gear near the clutch did
not engage. It seemed like something should have changed after energizing
the clutch. Then I removed the gears and clutch from the shaft that held
them. That's when I found that same type of sticky grease on the shaft that
was present on the solenoids that caused a paper jam failure months ago. I
cleaned the grease off with some alcohol, reinstalled the clutch and gears,
and this time both gears turned when the clutch was energized with DC. I
reassembled the printer and now paper processed through tray 1 works
properly every time. It turned out to be an easy fix but I never would have
thought to look in that area of the printer without your suggestion so
thanks very much for that. (-:

--
David Farber
Los Osos, CA