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Repair: Sanyo 20-EZ monitor

Another major colour 15 kHz chassis of US cabinets (~19-20″), very common — notably in Nintendo cabs (the 20-EZV variant with an audio board) and many US games. Standard CRT repair: HV discharge, recap (the 160 V caps first), plus two 20-EZ specifics: vertical collapse and board cracks.

Identification / variants

Chassis Note Typical use
20-EZ base colour 15 kHz chassis 1980s US games
20-EZV + integrated audio board Nintendo cabs (PlayChoice/VS…), revisions R-B / R-C
20-EZY variant per cabinet

Safety (read first)

High voltage — discharge the tube

Lethal high voltage held while unplugged → discharge the anode before work. See CRT safety & HV discharge. Isolation transformer for powered measurements.

Common faults

Symptom Likely cause Lead
Erratic brightness/deflection bad electrolytics, especially the 160 V ones Recap (160 V first)
Vertical collapse (a horizontal band) / partial collapse vertical deflection stage/IC, its caps Recap the vertical + check the vertical output IC
Intermittent dropouts / instability board cracks (the 20-EZ PCB cracks easily — hairline cracks across traces) Inspect under magnification, repair cut traces
B+ stuck low (e.g. ~30 V) regulation / supply Diagnose the +B / supply stage
Unstable horizontal sync H stage / joints Reflow, H diagnosis
Distorted / weak / no sound (20-EZV) audio board (bipolar caps, TR373 / TR374); JB/JC reversed → burnt resistors Audio recap + transistors; check the JB/JC connector orientation

Repair (method)

  1. HV discharge → CRT safety.
  2. Recap (method) — start with the 160 V electrolytics (No. 1 cause of brightness/deflection). The main 470 µF / 250 V filter (the biggest cap) is often NOT in the kits → order it separately.
  3. Inspect the board: the 20-EZ PCB cracks (hairline cracks across traces) → repair the traces (traces & vias); handle the board gently (it is fragile).
  4. Vertical collapse: the vertical deflection stage (IC + caps).
  5. 20-EZV — audio board: a dedicated cap kit + TR373 / TR374; ⚠️ JB/JC must not be reversed (or resistors burn).

Cap kits & parts

See also

Sources & attribution

  • Museum of the Game / Arcade-Museum — 20-EZ/20-EZV logs (160 V recap, vertical collapse, low B+, PCB cracks, audio TR373/374) — https://forums.arcade-museum.com/
  • arcadepartsandrepair / Paradise Arcade — 20-EZ/EZV cap kits (BOM cross-check, separate 470 µF filter) — https://www.arcadepartsandrepair.com/
  • Sanyo — 20-EZ service manual — 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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