Laserjet 4 error code "50 Service" help

[woodss]

The LaserJet 4 Series is still a reliable printer, just needs more care as they are a older machine, but if you service them well and fix all the known faults then the machine will work for a decade or so, or until toner can no longer be sold, the LaserJet II printer can be extermly reliable printer if they are service correctly.

Replace the fuser and power supply, and your be okay, thats how I deal with 50 Service Errors it can be the DC controller, but thats rare.

You can repair the fuser unit, but its cheaper and easier to buy a refurbished one, you can replace the fusers element to get the fuser working, but then you need to refurbish the entire fuser, its a lot of work, its quite a diffcult job.

Basic Parts that Make up a LaserJet 4 Fuser:

• Upper and Lower Fuser Rollers.
• Various Gearsm diffrent sizes too.
• The fuser chassis, and supports.
• Thermal Sensors and wiring.
• Bushings for upper rollers.
• Fuser Heater.

There is lots more, you need the service manual to know how to disassemble it.

If you do decide to go with repairing your existing fuser you must clean it first, and replace the parts above, they are sold as a kit at various places.

Thats the fuser taken care of, the power supply can have a capacitor that failing or gone hard since it has liquid inside there, you can go to any electronics store such as Radio Shack, and replace the capacitor as long its the same attributes such as voltage, such, then you need need skills for soldering and solder removal.

This is one way to fix your problem.