Sharp SF-7320 / SF-7370 Copier Service Manual – 1990s (P/N 00ZSF7370SM-E)

This Sharp service manual (P/N 00ZSF7370SM-E) covers the SF-7320 and SF-7370 desktop copiers, with model-specific optical adjustments, component replacement procedures, and electrical circuit explanations.

PDF Navigation and Diagram Readability

Text search and circuit labels: PDF text search and embedded bookmarks are unavailable. Small circuit labels are easier to read when enlarged. Horizontal distortion obscures some labels and connections in the side-lamp schematic even at higher zoom.

The download contains one printable English PDF with 80 pages. The total includes 73 technical pages, the front cover, one model-comparison page, two contents pages, one blank page, one battery replacement caution page, and the copyright back cover.

Paper Feed, Optical Alignment, and Fuser Service

These selected service topics are part of the manual, which also covers installation checks and programming the maintenance counter.

• Paper handling: Paper feed and resist roller replacement, separation tape installation, paper delivery roller service, and feed roller angle adjustment at the spring clutch.
• Optical system: Step-by-step procedures for restringing the mirror base drive wire, plus copy lamp replacement, horizontal and vertical skew correction, and lens positioning.
• Developer and drum: Developer unit assembly, doctor blade clearance, magnetic roller pole alignment, toner control sensor setup, cleaning blade replacement, and discharge lamp service.
• Fuser service: Upper and lower heat roller replacement, heater lamp service, thermistor and thermostat checks, separator pawl replacement, and paper guide adjustment.
• Electrical diagnosis: General and main control block diagrams, CPU signal assignments, sensor circuits, high-voltage transformer operation, and mirror and main motor control schematics.
• Maintenance and copy quality: Component maintenance schedules, fault-code definitions, gray-chart density checks, resolution standards, and image-loss limits.

The circuit analysis and calibration procedures suit copier service technicians familiar with electrical testing and mechanical alignment. Corona output measurements require the specified DCD test sheet, harness, and meter.

Optical Alignment by Model

The SF-7370 has variable magnification with a lens carriage, lens position sensor, stepping motor, and movable No. 4/5 mirror assembly. The SF-7320 copies at a fixed ratio and has its own resolution and magnification check. The model-specific procedures help technicians select the applicable lens and mirror adjustments before alignment.

The manual also covers exposure balance, partial-focus correction, optical-axis checks, and automatic exposure sensor adjustment. Routing drawings show where the copy lamp harness runs relative to the mirror assembly.

Developer, Drum, and Fuser Reassembly

Developer drawings show side seal placement, V-ring orientation, and roller and gear assembly. A lifting developer side seal can damage the nearby OPC drum. In the fuser, the scraper can scratch the lower heat roller during paper guide installation. The fuser drawings show the positions of the scraper, cleaning roller, bearings, and protected wiring.

The maintenance chart distinguishes cleaning, inspection, lubrication, adjustment, and replacement tasks. Supply tables list regional consumables. For installation of the optional SF-MF11 multi-bypass stacker, Sharp refers technicians to the accessory’s separate installation manual.

Fault Codes and Control Board Setup

The fault table links mirror travel, fuser temperature, automatic exposure, toner control, and memory faults to their triggering conditions. This helps narrow a displayed fault to the relevant mechanism or sensing circuit before component testing.

Test-command coverage: The fault table is included on printed page 9-11. Printed pages 9-1 through 9-10 are missing from this PDF, leaving gaps in the dedicated command list and descriptions. Individual commands are documented where they are used for installation, adjustment, and main control board replacement.

The main control board replacement procedure covers regional setup, developer initialization, exposure calibration, and counter settings. The electrical section explains fuser temperature control, copy lamp control, and developer tank color identification. Follow the manual’s power isolation instructions when servicing high-voltage or heated assemblies.

Sample Fuser Clearance and Toner Identification Values

The specified thermostat clearance is 0.75 ± 0.25 mm with the upper heat roller pushed upward by the lower pressure roller.

For blue toner identification, the developer tank table specifies a 6.2 kΩ identification resistor and a corresponding input range of 2.42–3.17 V at CPU pin 6.