Nanao MS7-18 sync issue

[Blue0524]

I need some help! I’m trying to get the monitor in my Sega City all set up and it’s just not syncing. the volatages are at 4.72 and 12.13 but they won’t adjust evenly. The ground and sync wires are hooked up properly to the harness. Not sure where to go from here.

[grantspain]

4.72 on +5 line is not adequate

the fault you show looks like sync and video ground are reversed- show a photo of the video signal input connector

[Blue0524]

I swapped them just in case and nothing happened

[Blue0524]

I also bumped it up to 5v and it made 12v higher :/ I’m currently using the existing harness that was in my Sega City and hooking it up using a jamma pinout because the wires were cut to remove the original PSU and what I’m assuming is the small like filter board? Like the aero has. Is that correct?

[grantspain]

the last photo shows video ground and sync going to a power connector

[Blue0524]

I don’t understand. Sorry. Still pretty new. The black at the red wires are hooked up to video ground and sync on the harnes.

[Blue0524]

Would hooking up the harness directly from the harness to the ground and video coming off the monitor make a difference?

[geotrig]

Isthere any adjustment pots on the ms7-18?
I will suggest getting a good couple of pics of the chassis, wiring at both ends etc so we see what's going on, although grant is the master at this stuff to be fair

[Blue0524]

There are pots and I have adjusted each one to see if it’ll do anything and it doesn’t solve the issues. I’ve only messed with the ones on the right

[Blue0524]

Think i may have figure out whats going on with the monitor. If you look at the pic of the chassis there is 6 pins for the video connection but in my picture there is only 5 wires coming down. Im going to pull the monitor when i get home and follow the wires all the way to the chassis. Hopefully it wasn't cut.

[NoAffinity]

The connector should be for R,G,B,Sync,Ground. There's usually 2 grounds for whatever reason but they are continuous and only 1 needs to be connected.

But, it would still be good to trace the wires and make sure there's no knicking, damage, or cut, from one end to to the other, for those 5 wires.

[Blue0524]

Yes normally it would be 5. That’s the norm but not for this one.

[NoAffinity]

Which pin currently has no connection?

[Blue0524]

im not home to verify. but theres definitely 6 pins with only 5 wires coming down.

[NoAffinity]

Didn't realize the plug is right next to it. Looks like pin 6 (VD) is not connected. Just trying to decipher what those letters mean, it almost looks like pin 5 can be either positive sync or negative sync, and pin 6 is composite sync.

If that is true, then there should be a switch or jumper coming off of pin 5, to switch between positive or negative and possibly the switch is in the wrong position.

I could be completely off base here. Someone else, please feel free to jump in if you know better.

Also, what game is currently in the cab, and was there a game in it when you got it?

Lastly, games are more sensitive to 5V than they are to 12V. Get your 5V spot on, tested at the game board (some chip furthest from the edge connector).

[Blue0524]

Will pull the monitor when I get home. I was testing a single slot mvs board and a 60 in 1 board in it. It didn’t come with a board.

[NoAffinity]

If the MS8-26SU manual can be trusted as a "similar" cross-reference, the output connector appears to be similar. If you're lucky, you can follow the lines from the connector for those two (potentially different sync) pins, and will end up at an identifiable IC that the pinout can be referenced to know for sure what those pins are doing.

ms8-26su.png

:edit: this thread might also be of interest, some places to check for potentially irreparable damage.

https://www.aussiearcade.com/showthread ... eplacement

It also looks like there are connectors in the middle of the board, for 15khz and 25khz, similar to the MS8-26SU. It's worth a try swapping the connector. Possibly the cab was running a 25khz game at the time of its last use?

[Blue0524]

Alright guys just got home. There definitely is a cable missing. But I also noticed theres an empty spot where a plug should be.

[rewrite]

It also looks like there are connectors in the middle of the board, for 15khz and 25khz, similar to the MS8-26SU. It's worth a try swapping the connector. Possibly the cab was running a 25khz game at the time of its last use?

It was running SF2:WW during last use, so it was definitely in 15khz.

[NoAffinity]

You've got r,g,b,ground,sync. It's not missing anything. The sync pin may need to move to the currently unpopulared position but not likely. That is also the order the wires should be in. You can see r,g,b are color coded so that's easy. As suggested, follow the wires, make sure no damage along the way, and check the other end to make sure r,g,b are terminated correctly and white is terminated at video ground and purple at sync (I think those are the colors, based on the picture).

Also not missing anything at the 4-pin headers. Moving the female connector coming off the yoke from one header to the other flips the image

You should really check the fly back and areas suggested in that Aussie arcade thread to see if there's any signs of fly back failure. Also eyeball the whole chassis, see if there's are any signs of damage, missing components (ie legs without anything attached to them), etc.