cleaning solenoid on HPLJ6P

[Alan]

I'm having some paper jam issues with my HPLJ6P.
I've been advised that I should clean the solenoids.

Can anyone tell me more specifically how to go about that?
I do have the service manual but that doesn't mention this procedure.

Also it looks like a bit of a struggle to remove the case to get at
the innards, any hints on doing that?

 

[Baz]

I'm having some paper jam issues with my HPLJ6P.
I've been advised that I should clean the solenoids.

Can anyone tell me more specifically how to go about that?
I do have the service manual but that doesn't mention this procedure.

Also it looks like a bit of a struggle to remove the case to get at
the innards, any hints on doing that?

Hi Alan,

I had once this problem with my old HP Laserjet3-P. Took me ages to
diagnose, but as usual, I found a tip on the web, which put me on the right
path.

I think they are referring to cleaning the sticky residue that remains after
the "armature residual gap" material disintegrates and leaves it's glue.
Remove the armatures if possible and clean off the sticky stuff. You need
to fit some more material into the the armature gap to prevent the solenoid
"magnetically sticking". It provides a small air gap, and stops residual
magnetism from holding the armature. I seem to recall I've used small
pieces of stick on felt, but almost any non-magnetic material will do, if
you can keep it there. I temporarily used some clear plastic from a PET
bottle at one stage, but found the stick-one felt convenient.

The sticking armatures will affect the release time of the solenoids and
this causes the paper jam problem.

How to physically do it depends on how mechanically able you are. I'm
surprised the service manual doesn't tell you how to remove the case. After
that it's usually just screws.

regards
Barry

 

[LLCoolG]

Hi Alan,

I had once this problem with my old HP Laserjet3-P. Took me ages to
diagnose, but as usual, I found a tip on the web, which put me on the right
path.

I think they are referring to cleaning the sticky residue that remains after
the "armature residual gap" material disintegrates and leaves it's glue.
Remove the armatures if possible and clean off the sticky stuff. You need
to fit some more material into the the armature gap to prevent the solenoid
"magnetically sticking". It provides a small air gap, and stops residual
magnetism from holding the armature. I seem to recall I've used small
pieces of stick on felt, but almost any non-magnetic material will do, if
you can keep it there. I temporarily used some clear plastic from a PET
bottle at one stage, but found the stick-one felt convenient.

The sticking armatures will affect the release time of the solenoids and
this causes the paper jam problem.

How to physically do it depends on how mechanically able you are. I'm
surprised the service manual doesn't tell you how to remove the case. After
that it's usually just screws.

regards
Barry

Almost every one I worked on for pull jams was the pickup roller. EZ fix, try
that first

 

[Alan]

Hi Alan,

I had once this problem with my old HP Laserjet3-P. Took me ages to
diagnose, but as usual, I found a tip on the web, which put me on the right
path.

I think they are referring to cleaning the sticky residue that remains after
the "armature residual gap" material disintegrates and leaves it's glue.
Remove the armatures if possible and clean off the sticky stuff. You need
to fit some more material into the the armature gap to prevent the solenoid
"magnetically sticking". It provides a small air gap, and stops residual
magnetism from holding the armature. I seem to recall I've used small
pieces of stick on felt, but almost any non-magnetic material will do, if
you can keep it there. I temporarily used some clear plastic from a PET
bottle at one stage, but found the stick-one felt convenient.

The sticking armatures will affect the release time of the solenoids and
this causes the paper jam problem.

How to physically do it depends on how mechanically able you are. I'm
surprised the service manual doesn't tell you how to remove the case. After
that it's usually just screws.

The manual does say how to take it apart; what I meant was that it
does not mention anything about cleaning solenoids.

Also, in this model it appears you have to flex the case to get it on
and off, and I think the plastic is getting a bit brittle with age.

And embarrassingly, I'm not sure just where the solenoids in question
are and what it the solenoid actually looks like.
-- any pointers to an image?


I can see in a diagram in the manual "SL1 Tray 2 Solenoid" which I
guess is the one, as it's pickup from Tray 2 (the lower cassette) that
is the problem. It feeds from the MP tray at the front (Tray 1) okay.

The diagram that shows the location is fairly abstract, and I'm not
sure how much I need to dismantle the printer to get to it.

If you're interested, you can find the manual here:
http://www.freeprintermanuals.com/PM/HP LaserJet 5P, 6P Service Manual.pdf

 

[Alan]

Almost every one I worked on for pull jams was the pickup roller. EZ fix, try
that first

Thanks, but I've tried that. I clean the roller on my 5MP every now
and them when it starts to jam and then it's okay, so I know how to do
that, but this seems to be different. Also the 6MP does pickup from
the front MP tray, which uses the same pickup roller as the cassette,
so I don't think it is the roller.

 

[Baz]

The manual does say how to take it apart; what I meant was that it
does not mention anything about cleaning solenoids.

Also, in this model it appears you have to flex the case to get it on
and off, and I think the plastic is getting a bit brittle with age.

And embarrassingly, I'm not sure just where the solenoids in question
are and what it the solenoid actually looks like.
-- any pointers to an image?


I can see in a diagram in the manual "SL1 Tray 2 Solenoid" which I
guess is the one, as it's pickup from Tray 2 (the lower cassette) that
is the problem. It feeds from the MP tray at the front (Tray 1) okay.

The diagram that shows the location is fairly abstract, and I'm not
sure how much I need to dismantle the printer to get to it.

If you're interested, you can find the manual here:
http://www.freeprintermanuals.com/PM/HP LaserJet 5P, 6P Service Manual.pdf

Hi Alan,

I had a look at the manual, and whilst I'm not familiar with this printer,
have a look at page 82, "fig 35. Tray 1 Assembly" and you'll see a drawing
of what is referred to as a solenoid. It's the part with the number 4
pointing to it.

A solenoid is normally a hollow coil of wire with an iron core which is
attracted into it when current flows through the coil. In this case however
the units referred to as solenoids are better described as relays without
any contacts.

The moving part pivots towards the iron pole piece already inside the coil.
The end of the pivoting "armature" is used to perform some mechanical
function. In the case of a relay, it operates contacts. In the case of the
example in Fig 35, it looks like it pulls a tooth out of the clutch cog
wheel and allows something to turn for a certain time. Clean the gap of any
sticky substance, but make sure something is put in the gap to ensure the
armature doesn't actually contact the pole piece. As I previously said,
it's to reduce to chance of residual magnetism causing the armature to
stick. It's very common (almost always) in relays.

Hope this is some help.

Regards
Barry

 

[Alan]

I had a look at the manual, and whilst I'm not familiar with this printer,
have a look at page 82, "fig 35. Tray 1 Assembly" and you'll see a drawing
of what is referred to as a solenoid. It's the part with the number 4
pointing to it.

A solenoid is normally a hollow coil of wire with an iron core which is
attracted into it when current flows through the coil. In this case however
the units referred to as solenoids are better described as relays without
any contacts.

The moving part pivots towards the iron pole piece already inside the coil.
The end of the pivoting "armature" is used to perform some mechanical
function. In the case of a relay, it operates contacts. In the case of the
example in Fig 35, it looks like it pulls a tooth out of the clutch cog
wheel and allows something to turn for a certain time. Clean the gap of any
sticky substance, but make sure something is put in the gap to ensure the
armature doesn't actually contact the pole piece. As I previously said,
it's to reduce to chance of residual magnetism causing the armature to
stick. It's very common (almost always) in relays.

Hope this is some help.

Thanks, gives me a bit more background. Though I think the solenoid in
that diagram is okay, as pages from "Tray 1" (the multi-purpose tray)
feed okay, it's paper from the cassette (Tray 2) that jams.

Any recommendation for "something [to] put in the gap"?

Hopefully if and when I can get into the guts of it and see the
selenoid in question I'll work it out.

 

[Baz]

snip>
Any recommendation for "something [to] put in the gap"?

Hopefully if and when I can get into the guts of it and see the
selenoid in question I'll work it out.

Hi Alan,

Almost anything will do at pinch so long as it's non-magnetic. I first used
a piece of clear plastic from an old Jaycar package glued in place, which
worked fine, but later used a piece of self adhesive felt, which I decided
was probably more like the original. You can buy it at newsagents and
stationery shops. The main thing is to have a small air gap when the
armature is operated.

I used that diagram as an example of what the "solenoid" would look like.
If that one is easy to get to, check out what the condition of the material
in its airgap is like. If it's all sticky the chances are the rest are too.
Fix them all.

The one that gave trouble with my old Laserjet IIIP was involved with the
optional (underneath) paper tray, as the fold down "manual" tray was ok.
The problem was an occasional two sheet pickup, which became less and less
occasional until it was quite often. The sticking armature was throwing the
timing out of whack.

Barry

 

[Me&Mary]

When you're done messing with all that, take 5 min and put in a new $7 PU
roller.

 

[Adam]

I'm having some paper jam issues with my HPLJ6P.
I've been advised that I should clean the solenoids.

What's recommended for lubricating the moving part of a solenoid?
Dinosaur HPCLJ5M if it matters. Thanks!

Adam