sega turbo graphics ?'s

nuckinfuts68

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just got another sega turbo today. now, game play is fine except i have 2 graphics issue's that i'm tryin to diagnose where the prob would be.

1st issue is the cars and the scenery along side the road...( tree's and buildings only ) seem to have a flicker affect sort of. and during this sort of flicker the cars and the scenery seems to change from normal size to 2 times the size it should be. on the turns the cars stay the 2 X the size.

2nd issue is when you hit the tunnels the comp cars turn dark while my car stays bright. i know on the monaco gp game ya had headlights.....don't remember them on the turbo though.

now, are these issues gonna be an eprom issue or elsewhere??
 
Try reseating your EPROMs. Each one controls a certain aspect of the play - like the road borders, car 1, car 2 etc. You could also try reseating the Z80 CPU itself. Always good to check voltages as well.
 
I have a Turbo and had similar problems.

Sega used some funky analog-based components when designing parts of the the game. There are 2 pots on the main board that adjust the height of the trees/buildings/lines.

In addition, too much or too little voltage can cause the sides of the roads to turn from green to black, the sizes of things to be wrong, computer cars to be white/semi-invisible, etc... Check all outputs of your switcher at the switcher, board and far corners of the board and ensure they are close to 5.0 across the board, no pun intended.

Finally a few of these analog chips can go bad and need replacing. All 3 things were problems on one of my boards and it took me forever to find some 74LS626 chips to replace a couple of mine--luckily they were socketed. (They are a rare voltage controlled oscillator -- the analog voltage directly affects the frequency of oscillation that is used to draw screen objects)

LMK if you need a couple if you've looked at the other issues. I have a few extra to sell since they had a minimum order quantity when I got mine.
 
here are the screen shots. 1st 1 shows the main screen works fine with no flicker affect or size probs. 2nd shows the game just after the start and you can see the size of the cars are streched out badly. 3rd pic you can see the top of the building on the right is streched also.

turbo001.jpg


turbo003.jpg


turbo004.jpg
 
I don't see anything wrong with that...those are the WIDETRACK PONTIAC Indy cars.

Great idea I just had....bring them down here, and I will give them a nice home.

That one shot looks more like a doubble image to me for some reason.......
 
Old thread I know but just got myself a Sega turbo. All seems good apart from when you are driving in the dark. I can see my car but no co outer cars at all so I just keep crashing.
watching YouTube videos it shows the cars appear half way down the screen in the dark, mine are missing completely.
Any pointers where I can look please?

Thanks
steve
 
Old thread I know but just got myself a Sega turbo. All seems good apart from when you are driving in the dark. I can see my car but no co outer cars at all so I just keep crashing.
watching YouTube videos it shows the cars appear half way down the screen in the dark, mine are missing completely.
Any pointers where I can look please?

Thanks
steve
This usually means you need to adjust your monitor. Getting the right black level and brightness/contrast can be tricky.
 
Thanks for the reply. I will have to take a look at the monitor and see what I can do.
I will report back once I get chance to do it.
Thanks
Steve
 
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