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Atari Jaguar

Atari's last console (1993), sold as "64-bit". A complex multi-processor architecture (68000 + Tom & Jerry customs), cartridge-based (+ Jaguar CD add-on). A commercial failure, but a cult one. Native RGB.

Atari Jaguar board
Atari Jaguar board. Photo: Evan-Amos, public domain.

Identification

Field Value
Manufacturer Atari
Release 1993
Generation 5th
Native video output RGB (+ composite/S-Video)
Media Cartridge (+ Jaguar CD)

Architecture

Block Chip Clock Role
"Manager" Motorola 68000 ~13.3 MHz meant as a mere conductor… often used as the main CPU (a perf mistake)
Tom custom ASIC (26.6 MHz) Object Processor + Blitter + RISC GPU — the real graphics engine
Jerry custom ASIC (26.6 MHz) audio DSP (synthesis) + I/O + timers
Memory 2 MB DRAM (64-bit bus)
Media Cartridge (+ Jaguar CD add-on)

The "64-bit" marketing = a 64-bit memory bus. Reputedly very hard to program: the power is in Tom/Jerry, but many studios leaned on the (slow) 68000, hence disappointing games.

Jaguar CD, Memory Track & controller

  • Jaguar CD (1995): a double-speed add-on sitting on the cartridge slot, notoriously unreliable (the infamous "red screen of death" at boot). Few games; a collector's item.
  • Memory Track: a save cartridge (non-volatile memory) for CD games, which have no other save medium.
  • Controller: 3 action buttons + a 12-key numeric keypad covered with per-game cardboard overlays (Atari design heritage). The ProController adds 6 buttons.

Cartridge slot / loading

The cartridge port accepts a flashcart (e.g. a "Jaguar SD") to load the library and homebrew — the Jaguar scene has stayed active.

Common faults

Symptom Likely cause Lead
Cartridge not read Contacts Cleaning
Jaguar CD won't read Laser / add-on Repair / ODE
No image Power, contacts, customs Diagnosis

(Recap secondary depending on age.)

Revisions — K series or M series ✅

There is only one Jaguar model, but two revisions, readable directly from the serial number.

Revision Tell What characterises it
K series (1993 → 1993/94 or 1995) Serial number beginning with K Early units have some faults in the chips and build, but have an ADC in the controller ports — which allows analogue controllers to be used. ⚠️ Some K systems were produced later, eliminating the faults but also the analogue support.
M series (1993/94 → 1996) Serial number beginning with M Defined mostly by what it doesn't have: neither the K's chip faults, nor the ADC ports.

A common claim, explicitly unverified

It is often said that K series consoles work better with the Jaguar CD (a notoriously difficult add-on). The source flags this as unsubstantiated and in need of verification — we report it as such rather than presenting it as fact.

Hardware points worth knowing

The famous "toilet seat" shape, top-loading cartridge slot with easily broken cartridge pins, native RGB out at the back, and a "DSP" port — the one used by the JagLink network adapter, which apparently follows typical RS-232 conventions.

Reverse polarity protection — the preventive mod ✅

Neither the Jaguar nor the Jaguar CD has reverse polarity protection

Plugging in the wrong power supply fries the power regulator, two capacitors and a resistor. If you are servicing a Jaguar, this is the mod to do while you are in there: it is quick and purely preventive. (Source: ConsoleMods, CC-BY-SA.)

Part: a 1N5400 rectifier diode (protection up to 3 A). A higher voltage rated diode also works.

  1. Desolder the wire connecting a ferrite filter to the positive pin on the side of the power supply terminal. ⚠️ The wire colour varies between revisions — it may be black, red or white. Go by the location, never the colour (see the photo on the source page).
  2. Solder the diode to the now-empty trace where the filter wire was connected. The bar (or line) denoting the cathode (negative) side should face up; the anode (positive) side is soldered to the PCB.
  3. Solder the filter wire to the cathode side of the diode — the one with the bar.
  4. Clean any remaining flux with isopropyl alcohol.
  1. Locate C74 and C75, beside the power supply jack.
  2. With a razor, carefully cut the trace between C74 and the pad beside it. You don't need a big gash: two clean, thin lines perpendicular to the trace are enough to sever it.
  3. Confirm with a multimeter that there is no longer continuity between C74 and that pad.
  4. Solder the diode: cathode side (bar) to the pad, anode side to C75.
  5. Clean any remaining flux with isopropyl alcohol.

The test that confirms orientation

If the diode is soldered backwards, the console simply won't power on. That is the symptom to know: no mysterious fault, just a direction to reverse.

Region / 50-60 Hz ✅

The NTSC and PAL Jaguar motherboards are nearly identical: they differ only by the clock crystal and two jumpers set differently.

Item State Effect
R140 0 Ω resistor in place The system runs at 50 Hz instead of 60 Hz
R19 0 Ω resistor NOT in place The video encoder outputs PAL over RF, composite and S-Video
Crystal Y1 14.3 MHz (NTSC) → 17.7 MHz (PAL) The 17.7 MHz provides PAL's 4.43 MHz colour carrier frequency

Going to 60 Hz — remove jumper R140: it is on the bottom side of the motherboard, near controller port 2, possibly marked "R140". Heat each side, add fresh solder and remove the resistor. Tip: leaving it attached by one pad lets you undo the mod at any time. Switchable variant: fit an SPST switch and solder a wire between each leg and the pads, to toggle 50/60 Hz.

Setting the video encoder to NTSC colour — populate R19: the pad is on the top side of the board, near the cartridge slot, possibly marked "R19". Solder a 0 Ω resistor onto it.

The crystal governs the final result

If the Y1 crystal is not replaced, populating R19 yields NTSC4.43 (NTSC colour with a 4.43 MHz colour carrier) and not PAL60. Worth knowing before judging the result on a display.

What the source does not say (and we do not invent)

The ConsoleMods page leaves two explicit gaps: the exact SMD size of the R19 0 Ω resistor is an unfilled placeholder, and the Y1 crystal replacement section is an empty "TODO" (no modern compatible crystal is identified). We fill in neither: measure the footprint on your own board for R19, and source the crystal from the community.

  • Native RGB: the Jaguar already outputs RGB on its DB15 AV connector → just an RGB/SCART cable (or into an OSSC/RetroTINK) — no internal mod needed 🟢. Excellent stock picture.
  • Flashcart: the Jaguar GameDrive (RetroHQ) — games/homebrew on SD, plug-and-play 🟢. For the Jaguar CD (rare, fragile lens), a community ODE preserves the CD side.
  • Reliability: preventive recap + clean cartridge contacts (bad seating = crashes) and the expansion connector. The Jaguar CD often needs a laser clean/adjust.

Photos / assets

(To add: console, board, Jaguar CD.)

Advanced repair

Recap + cartridge/CD contacts; the (rare) Jaguar CD = laser/optics. Methods: Recap · PCB fault-finding · Traces & vias.

Sources & attribution

Image:

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.