Monitor issues with pics - can you diagnose these issues?

LordOfDoubleDee

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Monitor issues with pics - can you diagnose these issues?

Just got my monitor back from the shop and am struggling with two issues:

1. On the attract screen (most noticeable) but also on games like Solomon's Key (that have large single color fields) I am noticing broken diagonal white lines that scroll across the screen. Is not noticeable on games like Joust and Mario which are mostly fields of black.

2. When I boot up the machine, again on the attract screen, the top of the image is bent? Which means I need to grab my mirror and my non-conductive alignment tools and adjust the horizontal hold until it looks perfect. Which then the next time I boot it up is bent again. Note: this is the Rolling Thunder cabinet which has speakers right under (and next to) the screen. Speakers are shielded but those are two magnets that are pretty close to the monitor?

Note: everything looked great from the signal generator at the shop - could this be a PCB (19 in 1) issue?

See attached images and thanks for your help!
 

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Monitor Issues

Well from what I see could be a monitor to game mating issue. The lines are whats called moire patterns and the hook at the top of the screen is what we call AFC hunting. The horizontal sync circuit takes a fraction of a second to lock on to the sync pulse. Thats why adjusting the Horz Hold gets you close. So what type of monitor is it?
 
How is your sync connected? Composite sync on last pin only correct?
 
Good question - I did not wire this up and it looked suspect to me - I will go out and check it - from memory it seemed like it was attached to the last two pins - attaching a photo.
 

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Try moving that 2 pin connector over one pin to the right
 
http://arcadecontrols.com/BBBB/sync.html

attachment.php
 

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So I read the Bob Roberts article and moved over the video sync by one pin - viola! the curl is gone and another issue (not mentioned yet) was that I was also having trouble getting the horizontal position correct - it seemed like every game and even the attract screen were slightly off center - basically I had to pick which game I wanted centered (Mario Bros.) and the rest would be slightly too far right or left - once I moved the sync cable over a pin that issue was also solved but..

The moire pattern is still there on the attract screen and is noticeable on Solomon's Key - even on the grays/blacks - not noticeable on Mario. Bros, Joust, Robotron, games drawn over a solid black background.

The way the moire pattern worked did change: it would alternate directions - diagonal one way then the other and...

It seemed as if when the monitor warmed up it "settled" and then I would call them sparkles - almost kind of like the issue you have when you have a HDMI cable with too long of a run.

So now I'm wondering how I fix that issue :)

Thanks!
 
Reading more about moire patterns and CRTs - I'm not sure this is what I'm experiencing.

If you look at the above phone it is the broken white lines that are moving across the screen.

They are even spaced and are rolling.

After moving the negative horizontal sync pin I was getting the same lines but now they were less angled and the would scroll diagonally from the top left corner then switch direction and go from bottom right to top left.

Most noticeable on the attract screen and Solomon's Key.

Not visible on the test pattern when the game is in service mode?

Not visible on large fields of black like Mario/Joust/Robotron

I also shot a video on my phone - maybe I'll post that on Youtube

Would love to eliminate this and... this does not happen on my WG vertical monitor
 
One thing to check just to rule it out. Make sure your power supply voltages are correct. It's also possible you may have a bad capacitor. I can see from the pic of the chassis that not only did someone not do a complete cap kit, they also used cheap and possibly old capacitors.
 
Voltage are spot on now.

It makes me mad - I'm learning that no matter who you get a game from it is up to you to double (triple) check everything it you want to be totally sure that it is correct.

Still getting the sparkles/diagonal broken white lines - now they are alternating pretty quickly from left to right which almost creates a diamond pattern if you look for it.

But they do seem more faint - harder to spot.

As suggested maybe a brand new cap kit for this monitor - just to check that off of the list.
 
I would suggest that you start with a full recap. Make sure you get a B+ filter cap in your kit. None of the vendors seem to put these in their kits. Make sure whatever kit includes the bi-polars. I just did a cap job for someone and they gave me an arcadeshop kit they had bought. It did not include the bipolars. Go with arcadepartsandrepair.com if you can and add in the filter cap.
 
I would suggest that you start with a full recap. Make sure you get a B+ filter cap in your kit. None of the vendors seem to put these in their kits. Make sure whatever kit includes the bi-polars. I just did a cap job for someone and they gave me an arcadeshop kit they had bought. It did not include the bipolars. Go with arcadepartsandrepair.com if you can and add in the filter cap.

Great advice - will do - and thanks for the link!
 
Monitor Issues

Lord
Moire patterns aren't a fault of monitor failure but resolution of the graphics to the dot pitch of the tube. In the past I have turned up the contrast and defocused the tube slightly. This seems to help. The key is that some games show it while others don't. I have noticed this on some Multi arcade jamma boards with CGA monitors. Anyone else wanna chime in?
 
Lord
Moire patterns aren't a fault of monitor failure but resolution of the graphics to the dot pitch of the tube. In the past I have turned up the contrast and defocused the tube slightly. This seems to help. The key is that some games show it while others don't. I have noticed this on some Multi arcade jamma boards with CGA monitors. Anyone else wanna chime in?

Yes, this is exactly what I've been reading elsewhere - mismatch of the graphics to the tube - good to get confirmation on that.

Yes, I tried the defocus/contrast adjust - but.. didn't fix it and I want my monitor even sharper not less sharp :)

Which, with the reading I've been doing and videos I've been watching about moire patterns - I don't think that is the issue I'm experiencing. I've got broken, white, diagonal lines moving across the screen - moire patterns (and correct me if I'm wrong) seem to be gray or of a darker color and are (somewhat) more static.

Also, as far as the moire being a factor of graphic and dot pitch mismatch:

This does not happen on the 60 in 1 card - similar attract screen just vertical

Wouldn't the 19 in 1, a card created to be used in arcade cabinets with CRT and a CGA connection, be created in such a way that the resolution of the attract screen is designed to match the dot pitch of most CRT monitors?

Solomon's Key resolution (according to the arcade museum specs) has standard resolution - should match the monitor

Doesn't happen all the time, on all games, or all screens

This leads me to believe there is another issue with the monitor or an issue with the card itself

Going to try some different cards as well as putting this card in some other cabinets to see what happens

Thanks much for all of the help - it is getting better!
 
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So here's an update:

I was able to solve the issue with the white diagonal lines - long story short it was a grounding issue. When I got the game the ground pin was broken off of the ac adapter (of course) - so, right away I replaced the ac cable and wired it up properly with the correct grounding - the hobby 101 :)

After tracing the signal path over and over in an attempt to figure out what was causing the problem was and continuing to fix/double check each step I realized that that the switching power supply had the FG hooked up (previous owner). The FG on the power supply was screwed to the power supply chassis base. When tracing the power it looked like the ground from the wall ac terminated at the line filter. In my other cabinets the FG line was not used on the switching power supply.

As soon as I removed the FG ground from the power supply to the chassis base - viola! the white diagonal lines disappeared - so I guess this connection created some sort of ground loop? This ground loop was created when I returned to the ground pin to the ac power cord?

And, I'm assuming, that this may not have been an issue for the previous owner because the ac power was not grounded at the wall? And maybe, this grounding at the chassis base was needed because the grounding pin was snapped off and the power was not grounded at the wall?

If anyone has thoughts or feedback on this feel free to chime in.
 
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