Common symptoms
What can be investigated
Dead or unstable boardNo activity, excessive current, reset loops or supply rail problems.
Black or frozen screenClock, reset, CPU access, address/data activity and supporting logic.
Corrupted graphicsSprite, tile, colour, video RAM, ROM and bus-related symptoms.
Missing or distorted audioAudio rails, amplifier stages, sound CPU paths and obvious signal faults.
ROM and EPROM concernsIdentification, reading, checksums and comparison where reference data exists.
Physical board damageBroken tracks, sockets, corrosion and previous repair inspection.
Typical diagnostic sequence
- Visual and safety inspection. Orientation, edge connector, modifications, broken components and obvious shorts.
- Power rails and current behaviour. Verify voltages at the board, not just at the supply.
- Clock and reset. Confirm that the main processor has the basic conditions needed to run.
- Bus and logic activity. Follow address, data and control signals with appropriate tools.
- Targeted component tests. ROM reads, continuity, RAM observations and substitutions only when evidence points there.
Important limitations
Arcade PCBs often rely on custom chips, programmed logic and undocumented circuits. A board may be diagnosable but not economically repairable if the failed part is unavailable. Bootleg and heavily modified boards can also take longer because documentation and reference data may be limited.
Please supply the board name, photos of both sides, connector standard, previous repair history and the exact on-screen symptom before arranging delivery.
Arcade repair questions
Do you repair every arcade board?
No. Jobs are accepted based on board type, condition, documentation, parts and current workshop capability.
Can you test non-JAMMA boards?
Potentially, but the pinout and power requirements must be confirmed and an appropriate adaptor or test arrangement may be needed.
Will you replace every capacitor?
Not automatically. Capacitors are inspected and tested in context; blanket replacement is not a substitute for diagnosis.