Repair: Wells-Gardner monitors¶
Wells-Gardner (Chicago) = the monitor of classic US cabinets. Extremely common 15 kHz raster chassis (K4600, K4900, K7000), multi-sync (D9200/D9400) and the 6100 colour vector (Atari: Tempest, Star Wars). Standard CRT repair: HV discharge, recap, reflow cold joints, HOT/flyback.
Identification / range¶
| Chassis | Type | Sizes | Frequency | Typical use |
|---|---|---|---|---|
| K4600 | raster (older, open-frame) | 19"/25" | 15 kHz | 1980s US games |
| K4900 | raster | 19"/25" | 15 kHz | US games, very common |
| K7000 (K7100/7200/7300/7400/7500) | raster | 13" / 19" / 25" | 15 kHz | the US workhorse — the most common |
| U5000 | raster | 19"/25" | 15 kHz | Nintendo PlayChoice, etc. |
| D9200 / D9400 | auto multi-sync | 19"/25"/27" | 15 / 24 / 31 kHz | later tri-frequency cabs |
| 6100 | colour XY vector | 19"/25" | vector | Atari colour (Tempest, Star Wars, Major Havoc) |
Safety (read first)¶
High voltage — discharge the tube
Any CRT holds lethal high voltage even unplugged → discharge the anode before work. See CRT safety & HV discharge. Hot-chassis possible → isolation transformer mandatory for powered measurements.
Common faults¶
| Symptom | Likely cause | Lead |
|---|---|---|
| No picture / no HV | HOT (horizontal output transistor), flyback, +B supply | Check HOT, flyback, +B voltage |
| Intermittent dropouts / flicker | cold solder joints (neck, flyback, deflection connectors) | Reflow the hot spots |
| Image shrinks / blooms | dried electrolytics (recap), drifting +B | Recap, measure +B |
| Blur / defocus | flyback focus pot, tired flyback | Adjust focus, replace flyback |
| Washed-out colours / a missing colour | neck board / RGB amp, worn tube | Diagnose neck board, contacts, settings |
| Distorted/missing lines (6100 vector) | XY deflection / joints / generator | Reflow, deflection diagnosis; ⚠️ static spot = phosphor burn |
Repair (method)¶
- HV discharge → CRT safety.
- Reflow the joints around the HOT, flyback, deflection connectors and neck board — the K7000 is notorious for cold joints.
- Recap (general method) — well-documented vendor cap kits for the K7000.
- HOT / flyback = frequent wear parts (replace); focus / screen (G2) on the flyback, geometry via coils/pots.
- 6100 vector: same care as the Atari vector hardware (XY monitor, vector generator, deflection).
Cap kits & parts¶
- Console5 · arcademonitor.com sell per-chassis cap kits (K4600 / K4900 / K7000 / U5000…) — values pre-sorted.
- ⚠️ Cross-check against your board: several revisions per model.
See also¶
- CRT safety · Recap · Nanao MS8 / MS9 (Sega candy) · Hantarex (EU monitor).
Sources & attribution¶
- Museum of the Game / Arcade-Museum — WG chassis (K4600/K4900/K7000/U5000/D9200), rebuilds — https://forums.arcade-museum.com/
- Console5 / arcademonitor.com — per-chassis WG cap kits (BOM cross-check) — https://console5.com/store/arcade-kits/arcade.html
- Wells-Gardner — per-chassis service manuals (K7000…) — to reference
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.
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