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Oric-1 & Oric Atmos

The British 6502 that was a hit in France (Oric-1 in 1983, Atmos in 1984): an AY-3-8912 (3 voices), a decent keyboard on the Atmos, a nice game library. Standard 8-bit repair: recap, ULA, keyboard.

Oric Atmos

Oric Atmos — photo by Mathieu Charreyre, CC BY-SA 4.0 (Wikimedia Commons).

Identification

Model Year Note
Oric-1 1983 "calculator" keyboard, 16/48 KB
Oric Atmos 1984 real keyboard, fixed ROM (Oric-1 compatible)
Telestrat 1986 rare evolution (telematics-oriented)

CPU: 6502 @ 1 MHz; Sound: GI AY-3-8912; RF/SCART (RGB) output; cassette (and optional Microdisc drive).

Repair (technician)

  • Recap (external PSU + board) → Recap.
  • ULA: the custom chip is the weak point (as on the Spectrum) → cool/substitute if available.
  • Keyboard: contacts / membrane → clean.
  • Cassette: level adjustment / drive → loading was already finicky back then.
  • Video: SCART RGB output (common in FR) → check cable/RGB.

Procedure — a dead computer, step by step ✅

What this adds

Ordered for a home computer: what kills these is its power supply, its battery, its capacitors, its socketed RAM and its keyboard — roughly in that order, and well before the CPU. → PCB diagnosis

1. The power supply — measured before it is plugged in. This is the one step not to swap around. On a machine of this age a supply does not simply stop: a 5 V regulator that fails high puts 7, 9, 12 V onto the bus and takes the RAM and the custom chips with it. Measure every rail off the machine, under a dummy load if you can, and only then plug it in.

2. The battery, if it has one. Any RTC or backup cell soldered to a board is a future leak. If yours has one and it has never been changed, take it out before it takes the tracks with it. → Backup batteries

3. Capacitors. Recap is the default on these machines, not a last resort — and on the supply first, since that is what protects everything else. → Recap

4. RAM, on its sockets. These machines were built to be repaired: the RAM, and often the logic, sit in sockets. Reseat everything first — thirty years of oxide is a classic no-boot. Then swap chips: a bad RAM chip usually gives a repeatable pattern of garbage or a screen frozen at a fixed character.

5. The keyboard. A console does not have one; a computer's is a wear part. A membrane keyboard fails as whole dead rows or columns — that is the membrane, not the machine. A mechanical one wants its contacts cleaning, not replacing. Check this page: the failure mode is often documented per model.

6. Storage — tape or disk. Both often come down to the same things: a dirty head, and for tape the azimuth and a belt turned to tar. ⚠️ On the floppy side, check whether the mechanism actually has a belt before looking for one: many do, but some drives are direct drive, and hunting a belt that isn't there means stripping a drive for nothing. A machine that boots but loads nothing is a drive fault, not a logic fault — do not go looking on the board for it.

7. Video output. RF, composite, RGB or a dedicated monitor, depending on the machine (see Identification). Test with something else before you conclude: a period modulator and a modern TV disagree far more often than either is broken.

8. Still nothing. Now the logic: rails on the board, reset, clock, bus. → PCB diagnosis

Common faults

Symptom Likely cause Lead
No / unstable picture ULA / video Cool, substitute
Cassette load fails level / drive Adjust, clean
Dead keys keyboard Clean
Instability caps Recap

Modernisation & mods — what to buy, how

ULA = fragile part

The ULA is the weak point (runs hot) → cool it (heatsink) or substitute a community reissue. Recap + check the external PSU.

Modern storage - Cumulus 🟢: an SD emulator that replaces the Microdisc drive → mount .dsk images from an SD card, no more 3″ floppies. - Load cassette via audio 🟢 from a PC/phone (.tap → WAV) if keeping the deck; SD cards on the expansion bus per community builds 🟡.

Video - SCART RGB output 🟢 (common in FR) → sharp as-is; downstream OSSC / RetroTINK or RGB2HDMI (Raspberry Pi) for HDMI.

⚠️ Do not host ROMs/games — method only.

Archived technical documentation ✅

Manufacturer documentation archived locally: schematics, block diagrams, expected voltages, parts lists. The reference when a symptom matches no known fault.

  • Oric — board layout — PDF

Status

Manufacturer documents kept for preservation (machines out of production for decades), with no explicit licence — the same position as for the cabinet manuals already archived here.

Oric-1 connectors ✅

Connector pinouts.

Provenance

Undocumented origin in the collection these schematics came from: no author and no licence is stated there.

Oric-1 connectors — oric1 con

See also

Sources & attribution

Review & corrections

How this space is used

Spotted a wrong value, an outdated procedure, a chip reference that does not match your board? Say so here, with what you observed (model, board revision, serial number, measurement). Every report is cross-checked against a source before anything changes — an unverifiable correction is published as “reported by …, not cross-checked” rather than silently applied.

Reading is open to everyone; posting requires signing in with Discord. Reports from the wiki's declared reviewers are handled first; anyone else's are read too, but go through a human before anything is changed.