Buying a Sinclair ZX Spectrum: A Buyer's Guide

The Spectrum is one of the most approachable machines to start collecting — cheap by vintage-computer standards, still available in real numbers, and genuinely usable once it’s in your hands. That combination is exactly why I picked a Sinclair ZX Spectrum +2 as the first machine in this collection. This guide is the checklist I wish I’d had before buying it: which model to go for, what to inspect before paying, the faults that show up again and again on 40-year-old boards, and the mods worth doing once the machine is yours.

Which Spectrum should you buy?

“ZX Spectrum” covers a decade of different machines, and they’re not interchangeable in what they’re like to actually own.

ZX Spectrum 48K (1982) — the iconic rubber-key original. Get one for the look and the history; not for day-to-day comfort. The keyboard is famously mushy, there’s no built-in storage, and sound is a single-channel beeper.
ZX Spectrum+ (1984) — same 48K hardware, a much better case with proper keys. A good middle ground if you want the “classic” era without the rubber keyboard.
ZX Spectrum 128 “Toastrack” (1985/86) — the first 128K model, with the AY sound chip and RGB/MIDI out. Still cassette-only, still no built-in datacorder.
ZX Spectrum +2 (1986, grey) — the one I went with. 128K, AY sound, and — the big practical win — a cassette deck built into the case. No separate tape recorder to source or keep working.
ZX Spectrum +2A / +2B (1987/88, black) — same idea as the grey +2, built on the +3’s motherboard instead. Functionally very close to the grey +2; mostly a case-colour and market-availability choice.
ZX Spectrum +3 (1987) — the only floppy-based Spectrum, using Amstrad’s proprietary 3-inch discs. Closest thing to a “complete” retro setup out of the box, but the drives are the least reliable part of any Spectrum and the discs themselves are getting hard to find in good condition.

If you just want to use the thing, a +2 or +2A/+2B is the easiest starting point — built-in storage, no separate tape recorder or disc drive mechanism to keep alive. Add an SD interface (see below) and tape/disc condition stops mattering at all.

What to look for before buying

Before you commit to a listing:

A boot photo or video. Any seller who’s actually powered the machine on can show the copyright screen (”© 1982 Sinclair Research Ltd” or the 128K boot menu). No boot photo is a yellow flag, not necessarily a red one — but it changes what you’re paying for.
The case colour and condition. Cream/white plastics yellow with UV exposure over decades; that’s cosmetic, not functional, and can often be reversed (see Retr0bright-style treatments — search before you try it on your own unit). Cracks near the ports or expansion edge connector are more concerning.
Keyboard condition, especially on rubber-key 48K/+ models — sticky or unresponsive keys usually mean a degraded membrane, which is a known, solvable problem (see below) but worth pricing into your offer.
What’s included. Original PSU? Cables? Box and manual (rare and pricier, but not required to use the machine)? A missing PSU isn’t a dealbreaker, but factor in sourcing a correctly rated replacement.
Any visible rework on the board, if photos show the inside. Neatly reflowed joints or replaced capacitors from a competent repair are a plus, not a minus. Scorch marks, globs of solder, or components clearly wired in wrong are a real warning sign.
Serial number and case badge details, if you care about matching a specific issue/revision — useful for grey +2 buyers in particular, since motherboard issue numbers vary and some are more sought after than others.

Common problems

Every Spectrum on the second-hand market is now 35–45 years old. These faults come up constantly:

Dead or garbled video. Often the ULA (the custom chip doing most of the machine’s heavy lifting) or a RAM chip has failed. Sometimes it’s as simple as a dirty edge connector or a socketed chip that’s worked loose — worth reseating everything before assuming the worst.
Keyboard membrane failure. The flexible strip under the keys cracks or its connector corrodes with age, causing dead or “sticky” keys. Replacement membranes are still manufactured and are a well-trodden, beginner-friendly repair.
The mains capacitor (RIFA-style X2 cap) in the power supply. This is the one safety issue on this list, not just a reliability one — these capacitors are known to fail by cracking, smoking, or in rare cases arcing after decades of service, on this and countless other 1980s mains electronics. If the PSU hasn’t been serviced, budget for having this capacitor replaced (or replacing the PSU outright with a modern switch-mode one) before leaving it powered on unattended.
Perished cassette deck belts, on the +2/+2A/+2B’s built-in datacorder. Rubber belts degrade with age regardless of use; a deck that won’t play or rewind almost always just needs a belt kit — cheap, and a common first repair. Irrelevant if you’re loading everything from an SD interface anyway.
Floppy drive issues on the +3 — belts, dirty heads, and the general scarcity of known-good 3-inch discs to test with. The +3 is the most characterful Spectrum and the most fiddly to keep actually working from disc.
Degraded RF/composite output. Original video output was designed for 1980s TVs; expect a soft or drifting picture on a modern display straight off the RF modulator. This is normal, not necessarily a fault — see the video mods below.
Corroded edge connector / expansion bus. Common on units stored damp, and a frequent cause of “works standalone, misbehaves with any add-on” symptoms.

What to avoid

“Untested, powers on” with no video shown. Not a scam, just incomplete information — assume it needs at least a look, and price accordingly.
Water damage or musty/damp storage smell. Corrosion on connectors and ICs from damp storage is far harder to fully undo than most other faults on this list.
A machine bundled mainly for “a huge tape collection.” Cassettes this old are a coin flip to load reliably regardless of care taken, and it’s not why you should be paying more. Nice to have, not a value driver.
Non-original replacement parts sold as original, particularly keyboards and cassette decks — fine to buy knowingly, not fine to overpay for as “original.”
Very low prices with no photos at all. If it sounds too good to be true for a working, complete machine, budget for it needing real repair work, or for parts being missing entirely.

Modernising and modding it

None of this is required to enjoy a Spectrum, but it’s where the platform gets genuinely convenient to live with day to day.

SD-card storage. A divMMC-family interface (mine is the divMMC SinDiKat edition) loads software over ESXDOS from an SD card instead of tape or disc — the single biggest quality-of-life upgrade available, and it works across the whole 48K-through-+3 range. For the +3 specifically, Gotek-style floppy emulators are the equivalent fix for disc-based loading.
Video output. An RGB SCART cable (I use the Sintech RGB PRO cable) gets a genuinely clean picture on a modern TV or scaler without opening the case. For a step further, HDMI mod boards exist that fit inside several Spectrum models and output a clean digital signal directly — more involved, more permanent, and worth researching per-model before committing.
Joystick interfaces. Built in on the +2/+2A/+2B/+3 (Sinclair/SJS ports); 48K/+/128 owners typically add a Kempston or similar interface. A proper joystick (I use the ArcadeR9) makes a real difference over keyboard controls in anything arcade-shaped.
Preventative recapping. Replacing electrolytic capacitors in the PSU and on the mainboard before they fail, rather than after, is standard practice on machines this age — especially alongside dealing with the RIFA mains capacitor mentioned above.
3D-printed spares. Replacement feet, cassette deck parts, and even full keyboard components are widely available from the community for models where original spares are scarce.
If you want the Spectrum experience without vintage-hardware maintenance at all, the modern FPGA-based ZX Spectrum Next is worth knowing about as a parallel option — a new-production, backward-compatible reimagining rather than a mod for an existing machine, but relevant context when deciding how much original hardware you actually want to keep alive.

The short version

Buy the model that matches how you actually want to use it (a +2/+2A/+2B if you want built-in storage and minimal fuss), ask for a boot photo, budget for a keyboard membrane and a PSU capacitor check regardless of what the listing says, and treat an SD interface and a decent video cable as close to essential rather than optional extras.