Wobbly image on Wells Gardner 25k7191

[glewis]

I have a WG 25" running Groovymame. The image is great at  640X480 on Hyperspin and windows. It is also great on many games (mr. Do!) wobbly or wavy on others (mortal combat, arkanoid)
I don't know how to post videos so sorry
Any idea what might cause this wobble.
I have No magnets/speakers near the monitor.
The transformer sounds loud. So I am going to replace. (barely hear it with the cab closed but its humming/vibrating)
I will be doing a cap kit and flyback soon but not sure if that is a cause. Can wobbly screens be fixed with a cap kit when it only occurs on some games.
Thanks

[snappleman]

Wobbly like the picture has a wave or ripple going through or "under" it? I've had this happen on two monitors, once it was because the B+ pot was faulty, the other time was because one of the larger caps near the HOT was faulty. I'm not an expert though, so I would wait till one of the more experienced people here chimes in.

If it's only in certain games, especially with GroovyMame and if you're using CRT_emudriver then it could be some manner of resolutions/timings that your monitor isn't doing well with. I had this happen a lot with GM and CRT_emudriver. Mortal Kombat in particular runs at a lower refresh rate and some monitors have trouble syncing correctly.

[glewis]

It’s like a pulsing wavy flowing issue. Is the cap you mentioned a part of float cap kits or do I have to buy it separate. I will do the hardware parts but I want to make sure it’s not a software solution because the monitor does look great on many games. I think you might be right though about the gm crt-emu. I remember ~15 years ago I set up advmane and I remember making per game video changes until I got a stable image on many games that were wavy. I just don’t know how to do that with the gm crt set up.  Currently the majority of games Do look great.
Is it even possible to make incremental changes to crt_emu video modes like with advancemame?

[snappleman]

Yes you go into the ArcadeOSD and you can switch to each mode and see how well your monitor handles it, then you can go in and tweak the timings to possibly correct some minor issues. Depending on what the issue is I've also used the vertical/horizontal hold controls to get certain games looking right. Have you calibrated the monitor? Before I'd do any cap kit or flyback replacement I'd check to make sure everything is calibrated properly.

[glewis]

Not an official calibration but it is looking great. All games have correct geometry. I’ll try your suggestion with atcadeosd. I’ll keep you posted.

[glewis]

Ok so I ran arcadeosd I selected the resolutions in question. With millipede at 256x240 it looked great, but with the 2560x256@58p it looked like crap until I was able to increase the dot clock until the v (hz) reached 60. Now it looks great.
I also noticed that all the issues are on vertical games. And when I changed the orientation of a vertical game with the issue  to horizontal in mame by rotating, the issues goes away.  So doesn’t seem like a bad monitor or caps etc.
Any thoughts?
How do I force millipede and all games of similar resolution to use 256x240 instead of the current, would be better to replace the super res version with the super res with 60hz?

I remember there being an issue with vertical games on a horizontal monitor.
Any thoughts

[snappleman]

As far as I understand CRT Switchres (meaning not much at all...) it'll choose the resolution that's closest? You're best off asking in the GroovyMame forum on that one.

[glewis]

I’ll try the GM forum. The issue is that I am not sure if this is a software issue or a hardware issue