Troubleshooting HP LaserJet III Malfunction
Short summary:
If the HP LaserJet III printer shows 50 SERVICE after power up and the fuser is o.k. then maybe the AC Driver / Safety Circuit board of the AC Power Module is defect ...
Long summary:
Troubleshooting: HP LaserJet III Malfunction 50 SERVICE Troubleshooting: HP LaserJet III Malfunction 50 SERVICE Version Info: This is the second, optimized version of the troubleshooting description HP-LaserJet-III_Repair.doc.pdf dated mid 2003. Error 50 Service: If the HP LaserJet III printer shows 50 SERVICE after power up and the fuser is o.k. then maybe the AC Driver / Safety Circuit board of the AC Power Module is defect. This PCB with part number RG11438 is made from cheap PCB base material which can render a conductive path between adjacent feedthrough holes if it is old or was over heated. First Check: 1.) Switch off the printer and disconnect the power cord. 2.) Check the fuser module (see below) or replace it by a functioning one. 3.) If this does not help then replace the AC Power Module or repair it as described below: Remove the AC Driver / Safety Circuit PCB RG1-1438 from the printer: There is a good (but German) description with many photos from Johannes Schubert on how to open the printer. 1.) Switch off the printer and disconnect the power cord. 2.) Remove three screws (including washer) of the top cover. 3.) To remove the top cover firmly lift it on the back side (above power inlet) and press in (maybe with screwdriver) the right side panel (about six inches from backside) upper rim. 4.) Remove right side panel. See two screws (including washer), one near the power inlet and the other right, front side. 5.) Locate the AC Power Module (right, back side) including the power inlet, power switch and fan unit. 6.) Remove the black plastic air deflector / air filter holder (two black screws including washer) in front of the fan. 7.) Remove the fan unit (three screws) and unplug the fan from the defective RG1-1438 PCB. 8.) Take away the upper, metal sheet (three black screws) which covers the AC Power Module. 9.) Remove the two remaining, black screws which hold the upper PCB named RG1-1438. 10.) Unplug the light blue cables (10 positions connector J151). Take out the PCB RG1-1438. 11.) Check and repair it as follows: of 4 Check board RG1-1438 and prepare for repairing: 1.) Locate the following four circuits: Capacitor C153 (22F/25V) Resistor R158 (560k) Diode D155 Transistor Q153 (2SC1815) 2.) One leg of each of the circuit is connected to each other via one PCB track. Locate this track: (A) = Basis of Q153 (B) = Anode of D155 (C) = R158 (D) = Plus of C153 3.) Unsolder this one leg of each of the four circuits which goes to this one track. See colored marking and items (A), (B), (C) and (D). The capacitor C153 and the transistor Q153 need to be temporarily completely ...
Source: carnot.pathology.ubc.ca
Related
Whatdunnit? Diagnosing Image Defects in the HP LaserJet 5000, ... there are slight differences among
models. Thus, this article applies to the
HP LaserJet 5000 series ... toner
cartridge. All offices have at least one
person who claims to know exactly how to
fix ...,
more
TonerMaintenance and OEM Brands, ... If a Toner Maintenance Cartridge
affects the operation of your machine,
Toner Maintenance will fix ... Yield (Up
to) OEM SKU # OEM List Price Toner
Maintenance Brand SKU # Toner Maintenance
Brand List Price Laserjet ...,
more
Xerox WorkCentre C2424 vs. HP LaserJet 4345mfp, Xerox WorkCentre ® C2424 vs. HP LaserJet
4345mfp The WorkCentre C2424 is the easy,
versatile, and ... instant, detailed,
on-screen alerts with solution
instructions, so you can quickly and
easily fix ...,
more
