HP Laserjet 4 Jams + Noise

The exit jam kit will definitely fix the accordion jams if they are occurring when the paper is exiting the printer. If they're happening in the fuser, you could have a gear problem which would account for the clicking noise. You can easily pull the fuser out, just 2 screws. Manually rotate the gear and check for smooth rotation and any broken looking gears. Also check the gear inside the printer that mates with it. You can manually rotate that also.

thanks for your ideas. I did some further tests/ diagnosis:

1. No change to clicking when toner removed (also true when paper tray removed)
2. Print quality remains excellent, no problems
3. Fuser gears seems fine - it's the same clicking noise even when removed
4. I can't be sure but it seems like the sound is coming from the front rather than back of the printer and inside it. Appears to start/ stop at same time as wheels just above paper cassette turn.
5. Clicks about twice a second for 20-25 times when starting up. When first page of print comes through clicks a few times, goes silent and then clicks until print ends.
6. Accordion problem seems to have disappeared at least temporarily!

Martin

: How often does it click? I mean as in how many clicks per second? That would be a clue as to where it may be. If you have an extra toner cartridge laying around, swap it out just for grins. Also, if you put your hand on the printer , or listen real close to the printer while it's clicking, you may be able to tell what part of the printer it's coming from.

: Does the printout look normal in every way as well?

The next step gets tricky. What you need to do is remove the paper feed assembly. Then you have to plug it in outside of the printer and bypass the door interlock switch by holding it down. Power up the printer and you'll be able to tell where the noise is coming from. I suspect it's one of the gears in the motor drive train. It's just a guess at this point since I can't hear it.
This is the only way to isolate the source of the noise. The accordion jam will probably come back. It's usually intermittent at first, also dependant on paper stock used. We're here for you. If all this sounds a bit difficult, we do have a comprehensive tear down video of the HP4.