Have you tried to adjust the sync when this happens? Putting a LCD in is far from a plug and play operation. There’s no substitute for a good ole CRT.

A capacitor kit for your game is a good place to start. Those caps are old - even if you find the sync to adjust the fact that the image starts messing up after warmup can be a significant bad capacitors.

CRTs are a special beast that can give nasty shocks if you don’t discharge the capacitors and the tube correctly before working on them. There’s much more of a risk to getting hurt with the voltages and currents involved when working on CRTs, even ones that are unplugged, versus stuff in most pinball machines.

The KLOV forums has a whole section dedicated to monitor repairs, and Space Invaders is a common game:

https://forums.arcade-museum.com/forums/technical-videogames-monitors.43/

They also have a lot of stickies on troubleshooting, safety, etc. Also, they could help with CRT identification just in case your tube isn’t original.

CRT’s can be very dangerous if not discharged properly. Your best bet is to find a local tech who is experienced in recapping monitors and pay him to do it. It’s the one repair in pinball/arcade collecting that I always outsource. Are you familiar with KLOV? Their forum would be useful for help.

CRT work is one thing I personally don’t enjoy dealing with when it comes to home arcade repairs. It isn’t too hard learning to discharge things correctly, but even once I felt comfortable with that then you gotta deal with how delicate the neck of the CRT is. Overall the name of the game is being very patient and taking your time.

I’m sure you can tackle this job - just read up a lot first and be safe

Here is a video on some Space Invaders Deluxe that could be helpful to see someone else poking around:

There are a couple different makes and models of monitors used in Space Invaders.

Open up the back of the machine and take a picture of the monitor chassis (PCB) as well as the labels on it and post is here.

Once you figure out the exact monitor, order a cap kit for it.
You can do so with Peter (whom is a member here on pinside).

https://www.arcadepartsandrepair.com/

Can almost guarantee the caps are drying up and going bad.

Once you fix these monitors they are tanks and very robust.
Also the game is worth more with the original monitor.

The sticker on the tube is just for the tube.
Are there any labels on the monitor chassis or frame that’s in English? I’ve worked on a number a Space Invaders monitors, but never this specific one so I’m not familiar with this monitor. No worries, it’s the same basic principals. Yours is the Taito Japanese version rather than the Midway version, which is rarer and not what you normally see.

I would bet Peter at arcade parts and repair probably already has a kit made up for this.
If not, he can make one based on the values labeled on the capacitors.