Help with vertical games

[Elysium]

Ok, first let me preface this by saying that I understand that this is a fairly common topic, and I actually have read many of the threads here on the matter, but I just don't seem to quite see the steps to fix the issue in my case.

I have a Win10 PC, 5450, running the latest Groovymame/CRT_Emudriver, connected to a K7000 through a JPAC.

Most games work fine, but I can't get any classic vertical games (such as Ms. Pac-Man, Galaga, or Donkey Kong) to display anything but jagged screen nothingness.  I understand that this is a result of the resolution of the game and the horizontal monitor and so on.  I'm not particularly concerned at this point as to whether it runs interlaced or squished, I can't get it to display anything.  Newer vertical games seem to work fine.  Tons of Shmups I've tried and Gain Ground all load in various resolutions.

Treat me like an idiot and tell me the steps I need to do to get these old games displayed.

While I'm here, perhaps someone can help me with another strange issue.  One day I was messing around with various games, and I loaded Street Fighter Alpha 3.  Since then, whenever I try to directly load GroovyMame it boots straight into SFA3.  To be more clear, I get crazy jagged screen, then SFA3 which plays fine, then if I try to exit it goes back t crazy jagged screen.  Using Launchbox/Bigbox I can load other games perfectly fine.

[Calamity]

That happens because fitting all the lines vertical games need in a horizontal screen requires increasing the horizontal frequency. Depending on the preset you use, this increase will be bigger, e.g. generic_15 is the most conservative, while arcade_15 raises the frequency till 16.2 kHz.

If you're using arcade_15, try generic_15 instead.

Anyway, the solution is to adjust the H-freq (or H-hold) potentiometer in your monitor's chassis.

[Elysium]

Wow, that's a simple fix! It didn't even occur to me that there were more pots to adjust, because everything else is in the front of the cabinet (vhold, vsize, hposition, contrast, etc), but look at that one little guy in the back on the monitor board.

This also fixes my other issue, which is that apparently GM itself wasn't in hsync for some reason after trying all those other games, and it happened to be sitting on SFA3, so opening it and pressing enter launched SFA3...