Nanao MS9-29
Nanao (1994)
A 29" monitor featured in many machines, including the Sega New Astro City and Taito Egret II, in addition to many dedicated machines.The biggest feature this monitor has over the MS8-29 is a unified Contrast adjustment, which adjusts gain of all three channels in unity. In addition, changing gain will not offset the bias level, so color tracking is not distorted in proportion to the bias levels.This monitor supports 15KHz and 24Khz horizontal refresh rates.B+ Voltage
The main DC supply voltage, B+, can be checked using the TP2 test point. It is located in the center of the PCB, in the corner of the "U" shaped side of the heatsink next to the empty inductor location L505. The correct B+ voltages are:
'Rev. D "05A00585D1'
The main DC supply voltage, B+, can be checked using the TP2 test point. It is located in the center of the PCB, in the corner of the "U" shaped side of the heatsink next to the empty inductor location L505. The correct B+ voltages are:
- 15KHz: +76V DC
- 24KHz: +119V DC
'Rev. D "05A00585D1'
- Wire link between middle pin of Q550 and C558 (innser side, close to U550)
- 470pF capacitor between third leg of D101 and negative pin of C101
- 2.2nF capacitor between pins 1 and 2 of T501
- Cap marked "102M" between ground and pin 3 of CN902
🔗Known Games
No known games for this hardware.
🔗Known Parts
🔗Images and Diagrams
Block Diagram
Troubleshooting Flowchart
Schematic
🔗Repair Manuals
🔗Repair Tips
🔗 Pincushion and horizontal width adjustments do not work
Test or replace the transistor at Q508, which is a 2SD1944.
🔗 "Dead"
If it's dead, and the fuse at F901 is good, then your problem lies in the primary power supply. It may be a defective MOSFET at Q901, or the driving circuit is not working. A lack of feedback from the secondary side may also be a factor.If Q901 has a silicone insulator around it, it is a Toshiba 2SK1531. Otherwise, it is a K1723. It is likely either part works fine. Be mindful of insulation when replacing, as the heatsink is grounded (and is safe to touch).
🔗 Chirps after shutting down.
If a monitor is dead, or has shut off, you may hear a chirp minutes after removing power from the chassis. When the chassis enters protection, a capacitor is charged that maintains the "disabled" state. Over the course of a few minutes, this capacitor discharges, allowing the monitor to try to power up once more. This "chirp" is the sound of the chassis attempting to start up once more with what little energy remains in the filter capacitor.
🔗 Poor horizontal linearity
Horizontal S correction is provided by a switchable set of S-capacitors. A jumper labeled "E" connects to either CN507 ("Normal") or CN505 ("Wide"). This jumper connects or disconnects C531.
🔗 Horizontal blurriness, or trailing RGB lines
If a recap and adjustment of the focus knob on the LOPT doesn't make the image sharp, and you're sure it isn't the tube's condition, the video amp at U201 may need to be replaced. This is an M51387P. If the G2 control on the LOPT ("screen") is too low, and your bias controls are too high, you may have a limited white peak coming from the video amplifier, and should recalibrate the colors.
🔗 MS9 shotgun chip repair list
Replacing these chips might be a good move in desperation if a solution has not presented itself.
- Power MOSFET: either 2SK1531 in silicone sleeve or 2SK1723 with mica insulator @ Q901
- HOT: 2SC4692 @ Q506
- Diode: ESC021 @ D502
- Width / pincushion amp: 2SD1944 @ Q508
- 12V supply for RGB amp, etc: LM7812 @ U951
- RGB Amp: M51387P @ U201
- H-size IC: AN5551 @ U450
- Synchronization IC: LA7853 @ U550
- Vertical deflection IC: LA7838 @ U401
🔗 Heater Circuit and resistor
The heater resistor limits current going to the heater filament, which is on pins 9 and 10. As the filament can also be modeled as a resistor, the polarity is unimportant, and DC or AC voltage may be used. As the name suggests, it heats up.Like many tubes, the A68KJU96X is designed to have a heater voltage of 6.3V. This voltage is a function of the resistance of the heater filament as well as the current-limiting resistor.The heater resistor for the MS9-29 is located at R532, and is tucked between the LOPT (Flyback) and the heatsink.On the MS9-29N22, MS9-29T, and other submodels that are intended for use with the A68KJU96X tube, the heater resistor is a 3.3 ohm resistor.
🔗 Capacitor List
If a chassis has never been serviced, it would be wise to replace all of the electrolytic capacitors. The following list is adapted from ArcadeOtaku.C102 1uf 50vC107 22uf 50vC201 47uf 16vC202 47uf 16vC203 47uf 16vC211 2.2uf 50vC212 2.2uf 50vC213 2.2uf 50vC220 470uf 16vC221 100uf 16vC222 22uf 50vC280 10uf 16v (remote board)C332 10uf 250v (neck board)C402 470uf 16vC406 1000uf 35vC407 100uf 35vC408 100uf 35vC409 100uf 35vC411 2.2uf 50v (bi polar cap)C451 22uf 50vC455 10uf 50vC456 10uf 50vC457 10uf 50vC458 22uf 50vC459 22uf 50vC503 100uf 35vC513 10uf 250vC515 100uf 160vC554 1uf 50vC556 1uf 50vC561 47uf 16vC562 100uf 10vC951 180uf 100vC952 220uf 100vC953 47uf 160vC954 680uf 35vC955 180uf 25vC956 680uf 10vC957 10uf 35vC958 47uf 16v C911 1000uf 200vC101 1uf 50v