Sinclair QL Service Manual
The Sinclair QL Service Manual is Sinclair Research's official service documentation for the Sinclair QL. Unusually for a machine of its era it is written at full component level: as well as fault diagnosis it contains the complete parts lists, so every capacitor, resistor and semiconductor designator and value on the main board and the Microdrive boards is documented.
It is the primary reference for the Sinclair QL Maintenance Guide, Sinclair QL Troubleshooting Guide, Sinclair QL Capacitor Replacement Guide and Sinclair QL Microdrive Troubleshooting Guide.
Contents
| Section | Covers |
|---|---|
| Section 1 | System description — the 68008, ZX8301, ZX8302 and 8049 IPC, video generation, Microdrives, power supplies |
| Section 2 | Disassembly and assembly |
| Section 3 | System test |
| Section 4 | Fault diagnosis and repair, including the power-up screen diagnostics and the fault-finding guide tables |
| Appendix A | Known bugs and their remedies |
| Appendix B | User hints |
| Appendix C | Mandatory modifications |
| Appendix D | Microdrive fault finding |
| Section 5 | Parts lists (Tables 5.1–5.5), including the full capacitor and resistor listings for Issue 5 and Issue 6 boards |
Key illustrations include the QL block diagram (Figure 1.3), the Issue 5 and Issue 6 circuit diagrams (Figures 1.4 and 1.5), the motor location jig (Figure 4.1), the keyboard format (Figure 4.2) and the PCB component layouts (Figures 5.1 and 5.2). These are also available individually on the wiki — see the circuit diagrams section of the main article.
Download the Sinclair QL Service Manual here: Sinclair QL Service Manual.pdf