Robotron double image

Spyridon

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I had a Robotron with a bad power supply. I recapped the power supply (all voltages now good) and the game powers up, however, I have a double image on the screen.

IMG_8469.jpg


At this point, I'm not sure if this is a board issue or monitor issue. I did quickly plug in a G07 I had nearby but I couldn't get it to sync (and didn't have time to play with it much)

I have also upgraded all the RAM chips to 4164 chips.

Any suggestions?
 
The easiest thing would be to plug that monitor into another Williams game to make sure it wasn't the monitor. If the other game looks the same, it is the monitor.

Secondarily, if you have (or can borrow) a known working Williams MPU board, swap it in and see if that fixes the video issues. If it does it is the board.

At the board level, check to make sure the legs on transistor Q4 are not shorted and check the outputs of chip 6C (7474 dual flip flop) as this generates the sync IIRC.

ken
 
The easiest thing would be to plug that monitor into another Williams game to make sure it wasn't the monitor. If the other game looks the same, it is the monitor.

I plugged the game into my Satan's Hollow which has a K4600 in it. At first, I got the same sync problem as with the G07. A little movement of some wires and I got a perfect picture.
IMG_8486.jpg
IMG_8488.jpg


Looks like my boardset is good! :dance3:

I'm not going to worry about the monitor issue right now as I'm putting a new monitor in this cab.
 
possible you may have a monitor convergence issue - red gun looks like it is off quitre a bit.

have a look at te G07 monitor manual there is agood section on convergence there to help adjust the neck rings if that is the issue.

quick and easy test is to mark the current ring positions with white paint stripe, dry, loosen the ring clamp and move the ring associated with red to see if the double image changes. if no change, reset ring to original position and retighten ring clamp.

be careful! potential (no pun intended! well, maybe there was :D) for getting shocked doing this. couldnt resist. i prob need a monitor repair induction course as i currently have the capacity to do this sort of work, and i really get get a charge out of it. oh shut up! :D
 
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I plugged the game into my Satan's Hollow which has a K4600 in it. At first, I got the same sync problem as with the G07. A little movement of some wires and I got a perfect picture.


Looks like my boardset is good! :dance3:

I'm not going to worry about the monitor issue right now as I'm putting a new monitor in this cab.

Congrats. Always try the easy stuff first. I hate when I find out I did something stupid like use a bad monitor after I've swapped out a dozen chips. :eek:

ken
 
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