[rescue] Q: Laserjet 4050

Alessandro Mazzini mazzinia at tin.it
Thu Jun 9 11:21:04 CDT 2011

Andrew Weiss <rumbeard <at> mac.com> writes:

> Chances are that's a really easy repair.  Buy 15$ pickup clutch.  Take off
side covers, pop out old one put in
> new one.  It's most likely not a rubber thing.  Quite often the magnetic
pickup clutches wear in such a way
> that the printer appears to attempt paper pickup but when it meets standard
paper resistance the clutch
> doesn't fire correctly and registers a jam.  It's often easy to diagnose if
the pickup foot remains down and
> the paper feeds 1-2 inches before the jam.
> Andrew
> On 07 Jun, 2011,at 01:45 AM, Lionel Peterson <lionel4287 <at> gmail.com> wrote:
> Hello all,
> I have an HP LJ4050 that won't detect paper in Tray 2, and when I
> reach in and lift the sensor, it tries to pick up paper, but won't.
> This printer was tested good, then stored in a garage for a couple
> years. When I pulled it out and tested it today it exhibited the above
> issues.
> I suspect the rubber has gone bad on the various pick-up wheels, and I
> honestly have no interest in repairing it myself. My last page printed
> shows just over 715K pages on the printer, w/o a Maint. Kit ever being
> installed. (from memory, I can confirm)
> Anyone want this? I've also got an HP LJ2100M that will suit my
> low-volume printing needs (10 PPM @ 1200x1200), and I have no interest
> in learning HP printer repair to get the LJ4050 up and running...
> I am in Central Jersey, and will drive a little bit to deliver/meet
> someone - if interested, please contact me off-list.
> The HP4000-series printers are nice, but this just needs too much work
> for me to keep it. If no one wants it, I'm gonna scrap it.
> The price is, of course, free - unless you want it shipped, then actual S/H.
> Lionel
> Lionel4287 <at> gmail.com

Andrew is right, but actually is even more simpler to fix it, and has 0 cost
involved (fixed an hp4000 some years ago, using these instructions on a forum).

The pickup clutch in the 4000 - 4050 series, has a so called long term defect
related to the magnetic material filled inside the clutch.

It tends to get unbalanced, this way the weight is no more distributed as it
should and it creates too much resistance to the movement.
The solutions are 2, depending on your luck

Solution 1 : remove the clutch and hit it very hardly on a workbench or another
surface like that, do it a couple of times.

If you're lucky this will be enough to fix the issue. If not.. 

Solution 2 : open the clutch ( on one side it's closed by a kind of plastic cork
... remove it with care using a blade ), remove part of the internal magnetic
material (small metal balls, if I remember they suggested removing 30%) , close
and put back.

In my case the 1st method was enough to fix it...

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