Joust picture is upside down.

Muel

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I have a Williams Rev - (Stargate) board, it has been modded to work with Joust, Robotron and Sinistar. (Looks like a factory mode with the 30ga wire.) The board coins up and plays perfect.
The only problem is the picture is upside down.
I'm not sure why it would do this.
Any ideas?
 
I have a Williams Rev - (Stargate) board, it has been modded to work with Joust, Robotron and Sinistar. (Looks like a factory mode with the 30ga wire.) The board coins up and plays perfect.
The only problem is the picture is upside down.
I'm not sure why it would do this.
Any ideas?

Sounds like you ought to read through this post, it has some info about dip switches and yoke flipping.

http://forums.arcade-museum.com/showthread.php?t=78635
 
It's just the yoke plug you need to flip, takes all of 3-5 seconds depending on what monitor you have. Had kinda the same issue with a zookeeper, had to flip the yoke connector.. On another pcb (bootleg slither CPU) I had to change the frequency switch on the monitor.. Kinda cool, cause everyone thought the pcb was bad and I got it for free :)
 
It's just the yoke plug you need to flip, takes all of 3-5 seconds depending on what monitor you have. Had kinda the same issue with a zookeeper, had to flip the yoke connector.. On another pcb (bootleg slither CPU) I had to change the frequency switch on the monitor.. Kinda cool, cause everyone thought the pcb was bad and I got it for free :)

Thanks, I had thought of just swapping the wires on the yoke as well - the most simple fix!
..but since I constantly swap Williams boards out of this cab (kind of my test bench) it wouldn't work for me in the long run.

I was going for the more difficult fix: What is making the MPU board output video upside down?
 
Check pin 23 IIRC, on decoder ROM 4. It should be low. If it is high then it is flipped.

There is a jumper (W1) on the I/O board that puts it into cocktail mode if it is missing.

ken
 
Check pin 23 IIRC, on decoder ROM 4. It should be low. If it is high then it is flipped.

There is a jumper (W1) on the I/O board that puts it into cocktail mode if it is missing.

ken

Well, there's part of the problem - pin 23 is dead, no high or low!

I'm going to change out the pair of decoder chips (#6 & #4) to see if it's the decoder chips or the board itself.

The W1 trace on this board is intact, don't think that it's a cocktail mode issue - I could try it out with a Robotron board to see if the screen flips for P2.

I'll keep you posted!
 
Okay, I just checked with another set of known decoder PROMS (did this already but thought I'd check again with a 3rd set) same effect.

Also, tried with a Robotron boardset, and it did not flip the screen for P1 or P2 so a no go on the cocktail mode (wishful thinking.)

It must be something else if pin 23 is dead. I'll have to try and trace it back on the schematics.
 
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