Sinclair ZX Spectrum Service Manual
The Sinclair ZX Spectrum Service Manual is Sinclair Research's official service documentation for the 16K and 48K Sinclair ZX Spectrum and the Sinclair ZX Spectrum+. Like the Sinclair QL Service Manual it is written at full component level: as well as fault diagnosis it contains complete parts lists, so every capacitor, resistor, diode and transistor designator and value on the main board is documented — and it is documented separately for each board issue, which matters because the Spectrum's component complement genuinely changed between issues.
It is the primary reference for Sinclair ZX Spectrum Capacitor Replacement Guide, Sinclair ZX Spectrum General Maintenance and Sinclair ZX Spectrum Troubleshooting Guide.
The copy hosted here is the re-typeset Revision 1.3 edition prepared by Brendan Alford for the Spectrum For Everyone project, which combines the original manual with both of Sinclair's supplements in one document. One passage — the DC-DC converter modification in Supplement No. 1, section 9.2 — carries an editor's note warning that Sinclair's printed instructions for that modification are wrong and should not be followed; the parts list in section 9.13 is the reliable record of what each board issue actually carries.
Contents
[edit | edit source]| Section | Covers |
|---|---|
| Section 1 | System description — Z80A CPU, memory organisation, read/write operations, I/O, TV picture generation, keyboard scanning, tape interface, loudspeaker, and the on-board power supplies |
| Section 2 | Disassembly and assembly |
| Section 3 | Setting up and system test — the internal voltage check table, colour adjustment, sub-carrier and 14 MHz oscillator alignment |
| Section 4 | Fault diagnosis: getting started — test equipment, modification history, per-issue modifications, the 16K-to-48K upgrade and its link settings |
| Section 5 | Fault diagnosis: PSU and memory — the basic check table, the memory check procedure and the bit-to-IC fault table, keyboard structure |
| Section 6 | Fault diagnosis: input/output — symptom-by-symptom lists covering video, colour, keyboard, regulator coil and speaker |
| Section 7 | Colour, repair and upgrades — LM1889 pin signals, 16K-to-48K upgrade detail |
| Section 8 | Parts lists for Issue 2 and Issue 3 boards |
| Section 9 | Supplement No. 1 — Issue 4A, 4B, 5 and 6A boards, and their parts lists |
| Section 10 | Supplement No. 2 — Spectrum to Spectrum+ conversion |
Board issues it covers
[edit | edit source]Sinclair shipped Issue 1, 2, 3, 3B, 4A, 4B, 5 and 6A boards; no Issue 4 and no Issue 6 were ever issued. The manual body covers Issue 1 to 3B and Supplement No. 1 covers the rest. Capacitor values are not constant across that range — for example C1–C8 are 47 nF on Issue 2 and Issue 3 but 22 nF from Issue 4A onwards, and C44/C45 are not fitted at all on Issue 5.
Download the Sinclair ZX Spectrum Service Manual here: Sinclair ZX Spectrum Service Manual.pdf