HP LaserJet Printer Memory Types

Once the fuser assmbly has been removed from the printer, inspect the upper and lower rollers for damage, check the gears for execessive wear and broken teeth. If the gears look worn you may also want to look at the fuser drive gear inside the printer. Once the fuser has cooled to room temperature you can test the heater lamp/s and thermistor with an ohmmeter as desribed below. In most cases you when the fuser fails you will read opens so the actual readins are not that critical. Always use caution when examining the fuser - the surfaces may be hot and can cause burns.
HP LaserJet 4000
Remove the fuser from the printer and check the heating element for opens across the two larger pins on the right it should read 13-15 ohms. Also check the two small pins on the bottom right, they should read between 200k-500k ohms. Take all readings after the fuser has cooled to room temperature. Examine the lower rubber roller and teflon sleeve for damage.
HP LaserJet 4100
Remove from printer then using the Ref point check the three points on the heating elements mainly for continuity. When testing the thermsitors on the small pins be careful not to bend pins they snap into place. Take all readings after the fuser has cooled to room temperature. Examine the lower rubber roller and teflon sleeve for damage.
HP LaserJet 4200
	Remove the fuser from the printer and check both lamps with an ohmmeter. The readings are not that critical since most of the time if either of the lamps go bad they will read open. Also check the two small pins on the bottom right, being careful not bend the pins. Take all readings after the fuser has cooled to room temperature.
HP LaserJet 4300

HP LaserJet 4250/4350

HP LaserJet 8100/8150 Fuser Assembly

HP LaserJet 4/4+/5 Fuser Assembly

HP LaserJet 4v/4Mv Fuser Assembly
	You need to remove the transfer roller first, it just snaps into clips at each end- note the position of the paper sensor. Remove the five brass screws only then by the plastic levesorrs look at the ends of the fuser to see how it snaps in. You will need to push the cover outward slightly to release each end of the fuser. Pull evenly straight up. Do Not put the transfer roller back in with the fuser out.
HP LaserJet 2100 Fuser Asembly

HP LaserJet II/IID/III/IIID Fuser Assembly
Open the top cover and remove the four screws holding the fuser in the printer. Pull straight up and lift from printer. Make sure the clear plastic spacers under the fiser metal frame do not come out with the fuser. Remove the plastic cover to expose the lamp screw picture on the left. Using this point as areference check the readings on both sides of the connector pictured on the right. Eaxmine the gears and rollers.
HP LaserJet IIISi/4Si Fuser Assembly

HP LaserJet 5000

HP LaserJet 2100

HP LaserJet 5P/6P