SEGA Genesis Radica Portable

Hello, I'm working on my first portable system, a Sega Genesis portable, and ran into some problems. So I figured id post some stuff here and hopefully get some help and show off what I have so far.

sorry for the basic photo's. its a bit of a mess right now and I didn't think of taking progress pictures.

I decided to use an old Game Gear Case to fit everything in, added an extra button below the other two (I lost it for now, but its another game gear button)

I'm really close to finishing but for some reason my screen keeps rolling or going into black and white. I don't know if theirs a way I can fix this or if I need to get a new screen, at witch point I'm going to have to try to find one that I can modify to work off 5v.

I'm also trying to figure out what to use for batteries. I have plenty of room in the old battery holders, and the system only uses 5v. I figured that maybe I can use one of those USB battery banks? That way I don't need to worry about the charge circuit. Has anyone tried this? or does it seem like it wont work?

The audio is good enough. I just attached it to the game gears volume control. I was going to use the headphone jack, but I couldn't figure out how the game gears one worked :p

Anyways! give me any suggestions or tips! they will help a ton!
Screenwise, it's kinda hard to say where the problem lies - the first thing I'd try would be to use a different screen -even just a TV or whatever - and see if you get the same issue, and vice versa if you don't.

As for batteries, yeah, I don't see any reason why a USB battery bank wouldn't work. Probably pretty compact and reasonable quality internal design on anything above bargain tier crap.
Does you screen have a series of little black capacitors up the side row? Usually those are some flax brand Chinese garbage. Replace them with a good brand.

If the problem persists, Rolling screen on the genesis comes from voltage ripple in the power supply. Methinks if you were to power it off of a battery, you should be fine. For good measure you could try adding a 25v 100uF cap on the power poles.
It can also be the Sync lines on your screen. See if you can find a pinout for the chip on the back of the screen, and check the traces to see if there is any corrosion or flaxty connections.
Those are great suggestions! Thank you! I should have some capacitors at work I can try replacing with, so I'll try that and those other suggestions too as soon as I'm able!
I would think it's a weak signal or something if chroma and sync are dropping out

Cheap screens usually don't decouple the power input to the driver from the power supply. Because they use cheap, garbage brand chips, they also like to *Can'tSayThisOnTV* up timing if the power supply ripples even a little.
I tested the Screen on an N64 and it didn't roll in the title screen but it would during the game, so I tried replacing the capacitors but that didn't change anything. So I guess I'll have to look into a different screen.

I also decided to try out the sega on a different screen to make sure its still working. But it's not working now. I guess I must have damaged a part when i was trying to get the screen working on it.
So I decided to completely redo the wiring for the carterage connector just incase that was causeing the problem for why I was getting no picture.
While I was in there I cut out the bottom some more so I can have the board as close to the back as I can and take some extra pictures to show off.

After resoldering it all over again it works! I decided to glue some of it down to prevent it from happening again. (the wires break off a bit too easy sometimes when there moved)

I'm ordering a new screen and battery now. But I would like some input on a battery. I was planning to get a battery bank for a phone just to make things easy for me, but its hard to know what I can trust and how the size of the battery will be when i take it apart.
What would you guys suggest I do for a battery?
OK! I went ahead and used two battery banks. It didn't really work with the batteries in parallel so, I put the chargers in parallel instead! It's a bit odd but it works!
Now i'm just waiting for the screen to come in so i can finish it up.

I got a new phone so my pictures are much better quality now :D
I dunno exactly what you did but it sounds unsafe.
Haha. Truthfully I have no idea how safe it is. But its outputting 5V and I've had no trouble running and charging them so far.
If things seem like there getting a bit strange later on then I'll just set the second battery to only run the screen.
The screen I ordered finally came in! and its better then I could have hoped for! The board is nice and small, it can run off of 5v without any modifying, and the menu buttons are on separate board!

Because of how convenient the menu buttons where I decided to have them setup in one of the battery holders since there's a good amount of extra space in there.

Here it is all finished and working!

I'm pretty happy with how this turned out.

There are a few things Id like to change out at some point:
A mono amp as well as a proper headphone port (the sound isn't great right now)
Fix the buttons so i can have the case closed tightly. and possibly find a way to make the buttons quieter.

But overall I'm pretty happy with how my first build turned out! :D