Nanao MS-2931

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The Nanao AmuseScan Multi 29 MS-2931 (usually referred to as just MS2931) is one of the last CRT monitors produced by Eizo Nanao Corporation. The monitor was produced from 1998 to the early 2000s. It is a trisync auto-switching monitor capable of 15k, 24k, and 31k resolutions, and can accept input from both DB15 and Jamma. It has an OSD for painless adjustments. Many call it one of the finest CRT monitors ever produced.

Tech Specs

MS-2931 Specs.png

Cap Map

Cap Map provided by uncletom.
MS-2931 cap-map.jpg

Tube/Yoke Information

The MS2931 and MS2934 share the same tube and yoke, only the chassis differs. It is a Toshiba tube with less curvature than an MS9 but more than a 29e31s on the longer side (the horizontal side if in yoko orientation). The MS2930, MS2931, and MS2934 are all compatible with each other. The correct replacement chassis is a Wei Ya 3129b or Rodotron 666b.

Known tubes:
Toshiba A68KJU96X / MS2932  : H :0.4 Ohms V:7 Ohms
Toshiba A68LBT696X / MS2931 : H :0.9 Ohms V :6.8 Ohms
Toshiba A68KZN696X / MS2930 : H :0.5 Ohms V:6.7 Ohms

How to Use the OSD

To bring up the normal menu, press mode. This gives you adjustments for H POS, H SIZE, V POS, V SIZE, CONTRAST, BRIGHTNESS, DEGAUSS, and RESET. A Degauss can be performed every 250 seconds. To use the reset function to restore factory settings, go to reset and hold down or up for a few seconds. To cycle through all of the options, use the mode button. To go back up to a previous option, hit mode and down at the same time. To bring up the extended menu, hold down for five seconds. This gives additional adjustments such as TRAP, PARA, HLIN, VLIN, SPC, CORNER, and more. You can also access all of the normal menu's adjustments within the extended menu. Resetting the extended menu works the same way as resetting the normal one.


The "black goop of death" has nothing to do with the failure of a MS2931 chassis. The black goop is potting compound released from the 750 A1 component near the flyback transformer. It is not actually your flyback melting. The potting compound is non conductive and is simply a sign of age. Some monitors may have an issue with the protection circuit; this can lock you out of some of the resolutions and may make you think that the monitor is dead. Jumping H sync and Vsync together should change the resolution and revive the monitor. It was rumored on the Japanese forum 2ch that there may have been a batch of MS2931 released around 1998 which was more likely to experience failure, however it is unknown what the fault is and whether or not it affects only all or some MS2931 manufactured in 1998. Net city monitors (ones made from 1999-2000) may or may not be affected.


The MS2931 is one of the rarest monitors, since it was used in relatively few cabinets and was released right before Eizo Nanao stopped production of CRT monitors. Currently, as of 12/5/09, Sega of America has two left in stock for 750USD. Craig at Giz10p has two of the chassis left, selling for 450 pounds each. The MS2931, in addition to being purchasable as a separate monitor, came stock in the following cabinets:

New Blast City, Net City (sitdown), Net City (upright), Sega F355 Challenge, Airline pilots Deluxe