G08 Retrace Lines Help

ComputerSpace

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Hello all,

The G08 in my Star Trek (Sega Multi-game) from time to time will display retrace lines on the screen. For example, the stars in Star Trek will have faint retrace lines playing 'connect the dots' on the screen. When this happens I will have a pinpoint bright dot in the middle of the screen as well.

I have the brightness turned all the way down and still I have a dot in the middle and retrace lines.

According to the G08 FAQ, I need to turn down the red drive on the monitor neck board. There are 6 pots on the neck board. 4 on one side and 2 on the other side. I have found no where that identifies which pots are which by name and or location.

Can anyone point out to me which pots are which on the neck board? Specifically, I think I need to turn down the red drive on the monitor.

TIA
Tom
 
You're supposed to just fiddle with them until you find the right one. How else are you supposed to learn? You can't learn anything without a few negative examples.

Looking at the monitor from the rear, the pair of potentiometers closest to the top left of the neckboard will adjust the red gun output.

Top one is black level, next one down is red gain. Try the 2nd one. I suggest looking at the screen, even if you have to hold a mirror to do it, while adjusting the level.
 
You're supposed to just fiddle with them until you find the right one. How else are you supposed to learn? You can't learn anything without a few negative examples.

Thanks for the info. I would agree on the fiddling comment, however this is a working G08 and I'm not going to fiddle with it. I want to get in, then get out, and hope it continues working.

Thx again. I'll give that a try.

Tom
 
Just a quick update in case someone else has this issue...

I had the power supply rebuilt since it had the burnt AC connector problem and I had to take it apart to replace the molex connector.

I installed the rebuilt PS.
Changed the burnt molex connector.
Discovered that the internal earth grounding was hooked to nothing so I corrected that and connected all items inside the cab to the ground.

Still had the retrace lines and the video was now 'wiggley'.

I disconnected the earth ground to the G08 chassis and the picture is rock solid again, no more wiggleys. I'll have to look into that one but for now the picture is great but with retrace lines.

I took kstillin's advice and adjusted the neck board pots. The red drive did not really affect the retrace issue, but the black level did. Adjusting that control removed the retrace lines.

Perfect picture and bright too.

Thx for the help.

Tom
 
Would it also bloom a bit at the beginning of each level? Mine does that and I'm probably going to do a cap kit.. but the earth ground issue would be way easier to try first.
 
Would it also bloom a bit at the beginning of each level? Mine does that and I'm probably going to do a cap kit.. but the earth ground issue would be way easier to try first.

Yes, it does now, but it never did this before I lowered the voltage to the monitor. I'm just chalking it up to the lower voltage. I'm just going to live with it since the lower voltage is easier on the monitor.

I don't think you need a cap kit. That is unless you did not do the Mongo voltage tap modification...?
 
Already did the tap mod.. not the earth ground. The lines do kinda get a bit gittery sometimes though.
 
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