The NEW Build Your Own Arcade Controls
Main => Monitor/Video Forum => Topic started by: nipsmg on January 02, 2019, 09:46:23 pm
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So according to the service documentation I can find for the k7000, the video hookup has r,g,b,gnd, +hsync, +vsync, -hsync, and -vsync.
I’m planning on wiring up a connector and driving this monitor with crt_emudriver.. Should I provide the arcade monitor both hsync and vsync, and, if so, do they go to + or -?
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So I wired up a vga breakout cable and hooked it up. Started up GroovyMame forcing a 240 p signal.
I’m getting the following.
(https://i.imgur.com/n9bRcJKl.jpg)
This is with hsync and vsync both wires up to the hsync- and vsync- terminals on the chassis respectively. Any suggestions?
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Ok, so chalk up that craziness to a crappy vga cable
(https://i.imgur.com/VwUbpZVl.jpg)
New problem though. Any idea what those vertical stripes are? They are stationary, don’t move or waiver.
Note: this monitor has been recapped.
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Do the vertical stripes get fainter from left to right? I can see that initial dropoff, but how about after that?
And did the chassis come with a detachable remote board? Like, size and brightness controls connected by a detachable cable so they can be located near the front of the cab for easy access?
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Yes, they drop off from left to right.
The chassis has a remote board, but not "detachable" -- it has Vsize, brighness, v & h hold, and blk level, but it's wired directly into the chassis-- long enough to locate close to the front of the cab for access.
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Hmm, noting that the board might be live, can you try moving it around while on, or at least moving the cables to it, towards and away from power sources, yoke and/or flyback and chassis inside the cab? At the same time watching if anything changes with the lines on the screen.
No need to make new threads, btw. You can bump your old ones.
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Yeah, i’ve done that. No change. I did get some feedback over at KLOV that with some versions of this chassis (K7000a), the 4.7uF cap used in the k7000 cap kit to replace a neckboard cap (c204) is not sufficient, needs 22uF 160V. Going to try that tomorrow.
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Replaced c204 with a 22uf 160V cap and replaced c57 with a 100uf 350V cap.
(https://i.imgur.com/pJwmADXl.jpg)
Still there. Any other suggestions?
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I'm out of easy ideas, sorry :(
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Ehh.. after adjusting the issue it looks good enough.
I've got a real WG (non-zenith) k7000 on the way from Ebay. I'm going to recap that and replace flyback and see how that does.. if it works I'll sell this one. I've gotten it to a point now where it's really not noticeable when playing.
(https://i.imgur.com/p8TVQBpl.jpg)
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What did you do to mimise the issue?
I turned up two more things that might help. The first is sony specific, but might still have some relevance.
That you have have is called yoke ringing and is different because it's a wave throughout the raster. It happens when there is an impedance mis-match between the yoke and flyback. On Sony, there were some caps in the horizontal output circuit called "S caps" that would fail and cause this. They are not electrolytic caps but like blue ceramic caps. (they may not be blue) Check them for cracks. The voltage/capacitance on those was critical and might be hard to find. Google Sony S caps and maybe some info will show up.That is a tough problem to solve. Look for cracks on any of the gumdrop or disc shaped caps, likely the larger ones.
The second idea might be to do with sync. Forgive me if you told me this elsewhere, but how are you getting sync? Extron? combining it yourself? C-sync from crt_emudriver? If the latter, maybe try 1k pot in the sync line, and another between the sync line and ground (though be careful not to dial that one to zero and short your VGA output and cook the pot). Maybe use a 50R resistor and then the 1k pot for that last.
Then again, if it's working pretty much ok now, wait until it bugs you again and come back to it :)
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The yoke ringing thing makes sense because this was a tube swap, could be an impedance mismatch.
For sync from the Tekken board it’s one line only coming from the board, from the PC I feed in H and V sync separately.
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I played with Screen and Broghtness and black level until it was least visible. It’ still there, but minimized a bit. It’s more obvious on black screens.