Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: RayB on December 16, 2008, 11:49:48 pm
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What causes "streaking" or a sort of bleed in graphics?
I mention problems of no red, no DRIVE control, not CUTOFF control either with a G07-904. (thread here: http://forum.arcadecontrols.com/index.php?topic=81814.0 )
I also see dark streaking. It's quite odd.
I was already given very sensible advice to look at other caps I have not replaced. Can anyone suggest if the streaking seen in these screen shots could be related to caps too? If not, what other parts?
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For the red: check the drive transistors on the neckboard. It's also possible that the gun in the tube is too weak to drive red properly.
Easiest check yet: make sure that the red connection is actually connected! With my Xenophobe I was chasing phantom red issues until I discovered the harness wasn't making proper contact
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The red does that on my cabs when the brightness is too high...
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The red does that on my cabs when the brightness is too high...
Yes Ive seen streaking like that from brightness too. What's bizarre here is the streaking is DARK, next to light graphics, and overall the brightness is too dim actually (I had to brighten up those photos in Photoshop)
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Until you get the red working and the monitor is capped I wouldn't worry about the streaking. The streaking could be a result that the red is not being driven. Have you verified the monitor works with more then one board, then you would know if it is the monitor that has no red or the game PCB.
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You haven't mentioned which monitor chassis is installed, but besides the red, this type of "shadow effect" was recently mentioned on KLOV and fixed with a wiring solution for a particular chassis. Unfortunately, I don't recall the info, and KLOV is currently down....
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The red does that on my cabs when the brightness is too high...
Yes Ive seen streaking like that from brightness too. What's bizarre here is the streaking is DARK, next to light graphics, and overall the brightness is too dim actually (I had to brighten up those photos in Photoshop)
OH now I see it. I couldn't see the pics on the computer I was using when I posted that. I noticed Peale saying something about red. Looks like a good candidate for a cap kit.
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It's a G07-904. It's been capped already.
I'll test another board in it tomorrow.
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Is G07-904 and G07-CBO the same thing?? I have CBO on the main chassis frame, and 904 up on the tube shield.....
Tested other boards in it, same results.
Checked the wire too and it's connected well.
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Inverted streaks like that are often caused by coupling issues - the coupling caps will charge up and when the levels drop, the residual charge in the coupling cap causes the output of it to drop below what it was before the high part of the signal. If things wernt so blown out to the limit of the display you would probably see that the white area was slowly darkening across it.
You really need to put a scope across the video signal and check that the sag is not on the input to the monitor before blaming that. Can happen if you have a low impedance monitor on an output thats not designed for it. I havent looked too much into arcade boards but it happened heaps when using passive splitters on a VGA out that made it see less then 75 ohms that it should have had. I dont recall ever seeing a standard of termination on arcade monitors mentioned anywhere.
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I had the same problem with a Xenophobe cabinet that had a WG 4600. I had to run a ground wire from the monitor to the board to the powersupply ground. This cleared up all waves and lines on the screen. Turned out that the ground strap had corrosion that I could not see, so the ground was not connecting good. GL
R