Nanao MS8-26SG Monitor dead. Experts?

Glitch

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Have a Nanao MS8-26SG (SEGA #200-5187-15) that isn't responding or seeing any neck glow. Swapped with another spare Nanao chassis and tube does show a picture.

- Gets AC power at plug
- Both fuses are good
- Flyback appears fine
- No obvious burnt caps or resistors
- No obvious cold or broken solder joints

It simply seems isolated on the power side.

Any of the resident monitor experts have any advice on what to check? Is there a common list of items to check?

I can't seem to find any legible schematics other than the typical blurry ones online.

hires photo of chassis can be found here: http://i.imgur.com/7p1kumL.jpg. Help is appreciated.
 

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The two ac input wire at the back of chassis

and the two red wires are for the other two pin connector.

you dont use the long connector when your using the two short connectors.

I would suspect its a shared plug with the game power inputs.

All you need to check the chassis is the two wires for ac.


the nanao can be found under a PCB # like 05A00460c1

or 05A00455B1 very close but not the same cap kit may be different as well.

theres different version of the chassis. and the # can be found on all the chasiss

as a reference besides MS8-xxx

This is a HOT chassis and needs to have a ISO hooked to it.

Look closely at the components in the power supply

all components will relate to the location of the regulator

which could be a suspect, the 3 pin transistor hooked to the HS

at back of chassis. if no{ dc} at the fuse or at a TP that ties

in with the fuse.. heat sinks are not a good chassis ground..

there are test stakes on the chassis if you look closely.

theres Threads about this chassis and schematic and cap Map.

Good Luck!
 
Appreciate the help, the chassis does have "05A00455B1" silkscreened on it.

Also performed the following steps by grantspain on a different forum:

grantspain said:
check/change
C433 25volt 10uf electrolitic
R433 2k2 resistor (1/4 watt)
q401,q402-2sd1136
d431,d432
then change the hot
link: https://forum.arcadecontrols.com/index.php?topic=83816.0

Purchased (4) aero city cabs, all but one were working before being recapped - now only have 1 working chassis at this time. Caps have been double & triple checked, but there still isn't any neck glow or static when cab is powered up.

Is there a list of known issues or troubleshooting steps with these chassis?
 
Whats the B+ on the DC fuse?

Whats the line in voltage on your Ac plug?

This chassis must use the line voltage at 100v's Ac

If you can solder a wire to the neg-side of the filter cap for a good ground.

or the neg-side of the bridge rectifier will do and you can measure

some voltages.

I dont think any off the heat sinks are common ground.

the regulator should be a C3306 @Q901 check the parts in the power supply

if no DC.
 
I'm seeing 100V on the B+ and AC plug. We do not have ground on heatsink, which I believe is correct (as compared to working chassis). Diodes are not burnt, resistors are fine. All caps have been changed, which resulted in a non-working board.

There is a IC103-MA11423 chip on a small board next to the NANAO logo, what should voltages be on that board? On the schematic I have, I cannot see the values of the components, maybe someone has a more legible copy?

Help is appreciated.
 
I see a lot of original caps in the power supply!!

Ok, first off don't nobody bend the daughter boards straight

up and down, the pin's can get damaged. Unless you want to start trouble

leave it in place, for one, that boards supplys the horizontal pulse

after you check for bad connections to the board

measure the Ic pin 9 Vcc and Pin 14, Pin 15 with O-scope

for Horiz drive any thing there?

Heres the pinout

http://www.dz863.com/datasheet-8384187763-HA11423_Color-Deflection-Signal-Processor/

Whats with C451 its not sitting like the others?


Need to Check for a short H.O.T

Your Reg Transistor heatsink not very hot..

Check the B+ control, is not turned all the way up?

Has it been turned? Don't turn it yet, most have glue on them so they don't get

turned without knowledge of it's importance to the B+ supply.

Confirm @903 the regulator is good if it has the same voltage coming

in and going out it could be shorted too..

In the front of the chassis next to the big coil, is the Horiz-Drive transistor

Check your Collector Voltage and the base goes to pin 15 of the ic.

Looks like the parts you checked or changed was in the vertical circuit.

The dc for vertical comes from the flyback and should not cause shutdown

or dead chassis. There may not be enough difference between your chassis

number and the MS8-26SU or 05A00460c1 so we can go with schematic if

can read it.

I don't think its in shutdown, measure some more test points

when you get a chance.
 
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I had this chassis in a aero city and it does not require a ISO. As far as what's wrong I have no clue :) good luck and if there is anything I can check on mine let me know and I'll try to help you.
 
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