24khz on Nanao MS9-29A's

[ken_cinder]

My Nanao MS9-29A's are dual mode monitors in a Versus City cab (15khz/24khz). From what I've read it auto scans, and the points on the chassis for 15khz and 24khz respectively are covered with a black square DIP control box of some kind, so theres no switching leads to different connectors.

I have a problem with 24khz I can't figure out. I'm running a PC for MAME etc, using a Radeon 8500 for a video card. 15khz works perfectly, but 24khz does not. The problems occur on both monitors identically.

24khz modes display without rolling, but it appears as if there are vertically 4 overlapped fuzzy images onscreen at the same time. I can't figure out what is causing it, if it's a limitation of the video card (It SHOULD do 24khz) or if it just doesn't like the modelines I'm using.

I'm using "Soft15khz" to enable these modes, and I can put in user modelines, but I'm kind of lost as to the cause of this 4 ghosted overlapped images thing. Can anyone with knowledge of this, that may know what causes that, tell me what the problem is? If it's the default modelines supplied with soft15khz, can anyone suggest correct ones?

[grantspain]

ms9 are not auto sync,you have to move a jumper plug cn503,cn504 to swap from 15k to 24k

[ken_cinder]

Theres no cable/plug like I've read in Astro City manuals that use a different MS9 model monitor, just this black box that I can't seem to remove.
There appears to be a little "clip" in the side of it, but it refuses to budge and the connector portion of it is mounted to the PCB.

Shall I provide a picture, because I know what you're referring to via that Astro City manual, but my monitor doesn't have those connectors.



Black box in center, it covers marked points on the PCB for both 15khz and 24khz at the same time, and I can't seem to remove it. (Rather I don't want to try too hard and damage something I have no replacement part for)

[grantspain]

send me a photo mate,i have worked on hundreds of nanao ms8 and ms9 and never seen what you are describing

[ken_cinder]

Picture up in post before yours (I edited, I know most people hate double posting). My camera sucks up close, so excuse the blurry pic.

[grantspain]

thats a relay,
is this your monitor chassis??
http://www.jomac.net.au/Nanao%20MS9-29A-T-SU.JPG

[ken_cinder]

No, my pots for all the controls are down the right side (Looking from the rear) mounted directly on the main board (no daughterboard) with seperate 15khz and 24khz H freq pots on the left side of the PCB.

If you have an astro city manual, it's nearly identical to the diagram found in that. I can't seem to find a manual for Versus City cabinets anywhere, even for sale.

[grantspain]

astro city were ms8,new astro city were ms9
get a better pic of the chassis so i can id it

[ken_cinder]

Sorry, the manual IS a New Astro City manual. I'll try to get a pic of the whole chassis, kinda hard though as there is practically no room between the two monitors.

The chassis is almost identical to that in the New Astro City manual, only the 15/24 connectors aren't there, they are both covered by this relay. (I can read 15khz and 24khz with white outlines to underneath the relay)

[grantspain]

oh you may have a rarity,this could be a ms2930 chassis-is this a new vs city?
if this is a ms2930 then its a tri sync monitor that is switched via the control board under the cp

[ken_cinder]

No, standard Versus City made in 96 I believe. I know it's not tri sync, there are only 15khz and 24khz points and a normal 31khz signal makes the monitors shut themselves off entirely, requiring a minute or 2 cooldown before they will allow themselves to power on again.

I noticed something odd when taking my pictures. The sticker on the frame around the monitor says MS9-29A but the sticker on the tube says MS9-29S. I believe the only thing that really matters here is the chassis, so I figured I best get the model number off the PCB which appears to be 05A00675C1.

Here are the best pictures I can get without taking these beasts out of the cab.

 

The only other board connected, is the one on the yoke, and the small control board at the front of the monitor for outside standard picture adjustments.

You can see the entire thing out of cab here - http://www.medi-gmbh.com/chassis/nanaorgb.htm Just search for that PCB number on the page.

[grantspain]

can you post a photo of the control board

[ken_cinder]

From left to right: Contrast, R-Gain, G-Gain, B-Gain, Brightness | H-Size, H-Pos, V-Size, V-Pos and a small cap. No switches in sight.

[grantspain]

ok well its different from my schematics,it must be a later ms9 chassis and of course if the relay is there then it must auto sync if there is no dil switch
so all i can say is that the signal you giving it is not 24khz,it must be 31khz hence the quad pic
when i get back to work i am gonna check out my ms9-29a in my time crisis to see if they are the same as yours

[ken_cinder]

Ok first allow me to apologize for eating up your time. Secondly, I'll say I'm sort of new to this, but not electronics in general.

I assumed it was auto scan, and I was indeed correct. What I didn't look at, that I just did, was the horizontal hold. There are seperate pots for 15k and 24k.

Needless to say, my 24k is now working as it should, and I feel seriously embarrassed.  < Directed at self.

Thank you for your assistance.

[grantspain]

no worries as i just learnt something as well