Calling Jeff Liebermann: LaserJet 2200 duplex printing problem

That's because I don't read comp.periphs.printers.

That would be:

How did you determine that? The printer is at least 10 years old. By now, I would expect the foam on all three solenoids to have devulcanized into a sticky goo. Even the slightest release delay caused by the sticky goo will cause problems. At this point in time, it is better to just assume that all 3 solenoids need cleaning and new felt.

You should have taken out all 3 solenoids, cleaned off all 3 solenoids, and applied the replacement felt to all 3 solenoids. Only this solenoid: causes it to paper jam or feed more than one page, but if the other stick, there can be other problems.

You should also have checked if any of the solenoid cores are magnetized. They get that way after many years of operation.

Since all this was in my instructions, I suggest you re-read the web pages and please follow them this time.

That is the classic symptom of a paper jam caused by sticky solenoids. However, it is also a fair description of what happens when the separation pad (RB2-6474) is worn out or filthy. I suggest getting a "paper jam kit" or "maintenance kit" and do a general cleaning. It's cheap and easy. Something like this:

There should not be any ratcheting sound when you turn on or run the printer. I can't tell from where exactly what's wrong, but you may have reassembled the printer incorrectly after cleaning the solenoids. It could also be one of the other solenoids sticking. Use a stethoscope to locate the source of the noise.

Also, my favorite screwup is re-installing the solenoids at an angle, and then locking them down with the retaining screw. It looks right, but it won't work. Loosen (not remove) the solenoids and rotate until the hole in the frame aligns with the locating pin.

The distance between the first and 2nd page is a function of how sticky the solenoid might be. The longer the distance, the more sticky.

No. The various rotating shafts are self aligning. As long as you didn't take apart one of the clutches on the rotating shafts, it should align itself.

Good luck.

I moved the armatures until they touched the foam pads, and there was not the slightest sign of sticking.

No sign of permanent magnetism in any of the solenoids.

Those parts were replaced a few months ago. That solved the problem that it kept trying to pick up several sheets at once.

I wouldn't really call it a ratcheting sound. It's much softer and "gentler" than that. More like parts rubbing together.

The only solenoid I removed was the first one, the one that did have the sticky goo problem. I was very careful to position it correctly when I reinstalled it.

You have to smash the armature hard against the solenoid, simulating what the energized core would do, in order to check for sticky problems. I've found that even the slightest residue on the either the armature or core will cause problems.

This is for a different model HP printer, but with the same sticky solenoid problems: It still paper jammed on double sided printing even after replacing the pads. Here's a video of the residual magnetism problem with the same solenoids: (600K) and a rather marginal test with a compass needle: If you decide to use a tape head demagnetizer on the solenoid, be sure to unplug the solenoid from the circuitry or you may fry something on the motor controller board.

Ok, so much for that theory. Am I correct that it ONLY jams when trying to print double sided? Did you have the paper jam problem immediately after you replaced those parts, or did it take "several months" for the problem to appear? I'm thinking that something might have gummed up the feed roller or coated them with something stick, such as printing sheets of mailing labels with some of the labels removed. That will transfer rubber glue to the rollers.

I'll stand by my guess(tm) that it was reassembled incorrectly.

So much for easy and obvious solutions. I don't know what might be misassembled so the only way to find out is to take it apart again and look for problems. It's a bit tricky to get it to print while disassembled, but not impossible.

Good luck 2.0.

Even though I could detect no sign of stickiness on the other two solenoids, and no residual magnetism on any of them, I gave all of them the recommended treatment, and now the printer is printed double-sided without problems.

Thank you.

Perce

Nicely done. I assume the noise is also gone. I'm rather surprised you didn't find any magnetized solenoids, because every one had the problem to some degree. However, if you fix the pads so that there's no metal-on-metal when the solenoid closes, the effect of the residual magnetism is negligible.

Y'er welcome.