2003 HP LaserJet 1150, 1300 & 1300n Printer Service Manual (P/N Q1334-90928)

This Hewlett-Packard service manual covers diagnosis and repair of the HP LaserJet 1150, 1300, and 1300n desktop printers (P/N Q1334-90928, Edition 1, April 2003).

• Paper handling: Pickup roller and separation pad replacement, print-path cleaning, and troubleshooting for misfeeds, multiple-sheet pickup, skew, and curled output.

• Internal assemblies: Removal and replacement of the formatter, laser/scanner, fuser, motor, and fan, with access procedures for the ECU pan and paper lift plate.

• Functional checks: Engine tests, half self-test checks, drum rotation tests, heating element checks, high-voltage power supply checks, and paper path checks.

• Control-panel diagnosis: Light-pattern tables and secondary messages for fatal engine errors, laser/scanner faults, and 1300-series LIO and DIMM accessory errors.

• Service mode: NVRAM initialization, cold reset, PJL software commands, and internal reports covering configuration, page counts, supplies status, and installed options.

• Wiring and parts identification: Main wiring and optional paper feeder wiring diagrams, connector locations, exploded assembly views, and alphabetical and numerical parts lists.

This manual suits printer technicians who are comfortable taking resistance measurements and handling ESD-sensitive components.

Formatter, Image Formation, and Paper Feed

The operational overview explains how the Coldfire V3 formatter turns incoming data into dot images and how the Engine Control Unit (ECU) coordinates the print engine. It follows all seven image-formation processes: conditioning, writing, developing, transferring, separating, fusing, and drum cleaning.

Bidirectional parallel, USB, and LIO communication are covered alongside the printer-unit functional block diagram, high-voltage power supply circuit, and general timing diagram.

The paper-feed section identifies PS931, PS911, and PS921 and explains how their signals track paper availability, registration, and delivery. This links the jam-detection descriptions to specific points along the paper path.

Fault Isolation and Model-Specific Repairs

The half self-test helps separate image-formation and development faults from transfer or fusing faults. The engine test bypasses formatter processing to isolate print-engine problems, although the formatter must remain connected to the ECU.

Separate formatter removal procedures cover the 1150 and 1300 series. The 1300-specific e-label assembly, formatter ESD shield, and optional paper-feeder connections are identified, along with its LIO slot and memory expansion; the 1150 uses a parallel connector.

The removal chapter covers field-replaceable units only. The manual's 104 numbered figures include assembly-location views and exploded diagrams; accompanying parts lists distinguish model-specific and voltage-specific assemblies.

The fuser notes flag a fragile tab on the pressure-roller gear: breaking it requires replacing the gear, which is not included with the replacement fuser. The laser/scanner shutter lever also has tabs that can break during removal.

Follow the manual's power-isolation and hot-fuser precautions, and keep the laser/scanner protective cover in place.

Reset Functions and PJL Limits

Cold reset and NVRAM initialization have different effects on stored settings and page counts; initialization resets some parameters that cannot be restored. Cold reset also affects an installed HP Jetdirect card's settings.

The documented PJL method uses a DOS prompt and parallel connection, with DOS applications unsupported over USB.

Sample Fuser and Paper-Handling Specifications

These examples are a small selection of the manual's electrical checks and paper-handling reference data.

For the fuser heating element, normal resistance is 25 ± 10 ohms on 110V printers and 80 ± 20 ohms on 220V printers.

One left-skew specification for cut-sheet media is 0.8% (2 mm over a 250 mm length). The transfer roller, pickup roller, and fuser are each listed with an estimated 50,000-page life; replacement is based on wear or failure rather than page count alone.

Searchable Text, Bookmarks, and PDF Contents

Search and diagram detail: Main text is searchable, with embedded bookmarks for chapters, subsections, and the index. Small wiring labels require zooming and are not included in text searches.

One printable English PDF download with 224 pages: 14 preliminary pages, 198 chapter pages, 10 index pages, and two closing pages. Covers and blank pages are already included.