I need help with a nanao MS8-26SU

[theHaMMeR]

I bought a KI 2 that has a Nanao MS8-26SU  monitor in it. The screen comes up all blue with a red swirl, will try to post a  pic asap. I noticed on the chassis there is a plug for a degaussing coil that has nothing attached to it. I'm assuming this has something to do with the problem. What else should I look for???

[grantspain]

a gaussing problem will manifest itself in strange ways,the first thing to do is reconnect the degauss coil after a min of 5 hours without power to see what happens.
normally people disconnect degauss coils because a fuse blows,this is down to the ptc component shorting
a pic of the problem will help a lot more as you could have a drive transistor fault,i have posted other problems with these chassis in the past,on the whole this chassis is very reliable and of good quality

[theHaMMeR]

i have nowhere to connect the degaussing coil connector to, so what else can i do for this??

[grantspain]

i have nowhere to connect the degaussing coil connector to, so what else can i do for this??

explain please

[Kevin Mullins]

I noticed on the chassis there is a plug for a degaussing coil that has nothing attached to it.

i have nowhere to connect the degaussing coil connector to, so what else can i do for this??

So you have the actual plug end of the degauss coil.... but can't find where on the chassis to plug it into?

[theHaMMeR]

no.. the chassis came withe the female connection attached to for the coil, it but the two red leads coming off it had been cut for some reason. I can't figure out what the leads went to, I don't think there is a coil in this cabinet. I think whoever put the monitor in the cabinet hacked the coil and forgot about it. What else can i do to resolve the coil issue?

[FrizzleFried]

no.. the chassis came withe the female connection attached to for the coil, it but the two red leads coming off it had been cut for some reason. I can't figure out what the leads went to, I don't think there is a coil in this cabinet. I think whoever put the monitor in the cabinet hacked the coil and forgot about it. What else can i do to resolve the coil issue?

Purchase a hand held degaussing coil....

www.arcadeshop.com

[grantspain]

blimey thats a real bit of logical advice from frizzlefried,i am shocked

[theHaMMeR]

i was told a high power magnet from a speaker would do the same is that true??

[grantspain]

it will have an affect but it will not cure the probem

[theHaMMeR]

i also wanted to mention that only the blue gain and bias pots react to adjustment, is this because of the degaussing or is there something else wrong?? i will be able to post pics later tonight. thanks

[northerngames]

KI 2 runs on 15K is the monitor harness set at standard res. or medium res.

dunno if it matters but it can't be a good thing if the res. is not set right.

[theHaMMeR]

i finally got a chance to post a pic of the monitor. thanks for all the input so far.

[grantspain]

sort out the deguassing problem first or you'll end up farting around in circles

[theHaMMeR]

ok here's a new pic with what i hope is the degaussing problem solved. what's left is this, the pic is with all the red, green, and blue gain and bias pots turned all the way down. let me know what you think.

[Kevin Mullins]

Turn the SCREEN voltage down a tad on the flyback.
Just enough to get rid of the lines.
I can see the lines in both of your pics.

And yes you still need to figure out why it's not degaussing first before you continue with worrying about the colors being wrong.

[grantspain]

kevin is perfectly correct,at this moment you have the screen volts(located on the flyback transformer)far too high,you need to turn this down so your picture is just viewable-at this point you can use the background and foreground adjustments to refine the quality of the picture(taking into account brightness and contrast)
if you have degaussed you monitor via a manual degauss you should be o.k unless you move the cab(of course unless there a serious magnetic interference in the earth in your location)
if you wish to install a degauss coil around your tube you can fit anything you can find from an old tv and cable tie it to your corner mounting brackets then connect to the 2 pin plug you already have

[theHaMMeR]

thanks, you guys have been a huge help today. here's the latest picture, i'm still not getting any action from the red and green pots, i also noticed there is no contrast pot. i do have a brightness and that works.

[Kevin Mullins]

Disconnect the blu input signal and see if the red and green will adjust then.
You might actually have a problem with the blue circuit.

[grantspain]

the ms8 chassis have a remote board with many adjustments,sometimes the board is on the side of the chassis and sometimes it will be located via an extension cable elsewhere in the cab(usually under the control panel)
kevin suggested disconnecting the blue input signal,another thing you could do is use that blue input signal to check the red and green-this will prove a monitor related issue or a problem with the game board/video cable

[northerngames]

Mine don't have a board and all the pots are on the chassis can the remote board be added?

and if so anyone know where to get one.

that would be a nice addition to my set-up if I could add one to it.

[Wade]

I have two MS8-26 monitors and both of them have all the pots on the main chassis.  I didn't know they sometimes had a remote board, are they still MS8-26 or is there a slightly different name (like the SU part?)

Wade

[theHaMMeR]

ok here's the latest picture. i took the blue input off and ended up with this. i also tried swapping it with the red with no response from the red pot. i know the game board is good i tested it in another cab, it looks beautiful. where do i go from here?

[grantspain]

change the blue drive transistor

[theHaMMeR]

any chance someone has a schematic for this chassis, or know what transistor the blue drive one is?? thanks for all your help

[grantspain]

its on the neck card,you will have 1 transistor for each colour
a quick check is just to remove the blue drive transistor to see if you lose that blue washed screen and also regain the red and green

[northerngames]

I have two MS8-26 monitors and both of them have all the pots on the main chassis.  I didn't know they sometimes had a remote board, are they still MS8-26 or is there a slightly different name (like the SU part?)

Wade

mine is a ms8-26SU and only has pots on the chassis but if I could add a remote board somehow I would.

[phi ho]

The blue drive transistor is Q322  in the neck board.You also need to check all the related parts in the circuit that controls the blue gun of the tube.All of them have name start with the number 32,such as R321,L322,D323,.....

[theHaMMeR]

i pulled the blue gain transistor and now i get a black screen nothing else

[grantspain]

i pulled the blue gain transistor and now i get a black screen nothing else

now adjust the contrast/screen volts and colour pots to see if you get any change

[theHaMMeR]

i'm sorry i guess i should have mentioned that. i tried all the pots and got nothing. i did end up with lines again so i turned my screen volts down again till they went away.

[grantspain]

i'm sorry i guess i should have mentioned that. i tried all the pots and got nothing. i did end up with lines again so i turned my screen volts down again till they went away.

hmmmm,that don't sound good-either you have bent neck pins/all the drive transistors are faulty/broken trace/red and green signal from the game board is missing or whatever ic that used to decode the colour signal is faulty
you best way forward is to swap the blue transistor for another on the neck card then swap the colour input wires i.e if you swap the red input wire to the blue and still get blue on the screen you know that the red signal input is present so you can then progress to checking for broken traces and bent pins

[theHaMMeR]

thanks for everything!! here's the latest, i found a bad solder joint on the red transistor and fixed that. now i have barely any response from the green pots. the red and blue are great. i've attached the latest pic, it's with only the green input attached. it's a weird gray-green colored screen. let me know what you think.

[grantspain]

well its either the transistor or a broken trace,you can swap the transistor to prove that

[theHaMMeR]

does anyone know the transistor part #'s for both transistors on the green circuit of the neck board. i can't make out any #'s n either of them. i touched up all the solder points and i get a green flicker in the picture, then it goes away after a couple of minutes. i hope if i replace both of those it may fix the problem.

[Kevin Mullins]

Hmmmm...... what does the screen look like when you completely remove the video signal input? (it should be completely black)

That last pic is showing waaaay too much blue for it having just the green input connected.

[theHaMMeR]

i'm sorry i've been away.. yes the screen is completely black when i take the signal input off. i'm guessing i should still replace the transistors for the lack of green signal??