G05 working with screen image on left side only.

RobotWorkshop

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I have an Atari Red Baron upright with a G05 monitor. Although it seemed to take a few minutes to warm up the display on it looked perfect. I recently rebuilt the ARII power supply and all the voltages on that were solid. I'm going to go back and retest all the outputs to be sure. Just yesterday the display acted weird. The left side of the screen is normal but once it gets near the center the lines all bunch up with nothing on the right half of the screen. Since this just happened I'm not sure yet if it is a monitor problem or an issue on the main board sending out the proper signals. To my knowledge the caps have not yet been replaced on the monitor or the main boards. I want ed to see if anyone experienced this issue before and may have suggestions on if it may just need a fresh set of quality caps in the monitor or something more.

Thank You,

Robert
 
Most likely a monitor issue. It's common on these. Reflow all pins on the connector headers for the deflection board (which is probably the issue), as well as the HV board. Also do cap kits on both boards while you're at it, as they do go bad.

If that doesn't fix it, you may have a bad frame transistor. But it's more likely to be a cracked solder joint on the header pin for that transistor. If you flip the deflection board over and look at the header pins, you'll see that there are little circular cracks around the pins, which is the problem. Reflow all of them with fresh solder.
 
Most likely a monitor issue. It's common on these. Reflow all pins on the connector headers for the deflection board (which is probably the issue), as well as the HV board. Also do cap kits on both boards while you're at it, as they do go bad.

If that doesn't fix it, you may have a bad frame transistor. But it's more likely to be a cracked solder joint on the header pin for that transistor. If you flip the deflection board over and look at the header pins, you'll see that there are little circular cracks around the pins, which is the problem. Reflow all of them with fresh solder.

Thank you for the response and the suggestions! I'm familiar with the cold solder joints on some robots that I repair. I figured it was due for fresh caps in the monitor and will reflow any questionable connections. After hearing it may be a common issue will pay close attention during the inspection. I don't normally mess with monitors but did fix a Nanao crt for a different game (bad resistor and about 10 bad caps) so I hope this won't be too bad. When I pull the old ones out I can test them with a Sencore LC103 so I should be able to tell which ones are really bad and how far off they are.

Robert
 
That's fine, but honestly you don't need to test them, or fret about tolerances, etc. Just replace them all with brand-name 105-degree caps from a reputable source, and you'll be fine. (iankellogg.com has kits, and Ian is a well-known and reputable member here).

Most of the caps will probably measure ok, but it's more of a preventative measure, as they're 35 years old. Your root cause in this case is more likely the transistor solder joints.
 
Here is a picture of the screen as it is now. It was working perfect but thought it was time for a cap kit because I don't believe the monitor has ever been out of it. Parts are on order and I hope that and reflowing solder connections will fix it. I am not going to power it up or use it until the parts come in and replaced.
 

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The cap kit arrived and I went through the monitor today. I checked the old caps as I took them out and it was definitely time for a fresh set. Luckily the issue with the display on just the left half of the screen was a broken/cold solder joint. Actually several of them. I'm amazed that it had been working at all! I am happy to report that after installing the new caps, re-flowing all the solder connections at the connectors (and anything questionable) that the monitor is working perfect. Had a chance to clean the blue filter and bezel and the screen looks amazing. Just need to rebuild the joystick and this Red Baron is done for now.

I've attached pictures of the fractured solder connections on the board.
 

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Well, I thought I had it wrapped up. Apparently I'm not quite done yet. Now when playing the game I'll notice the vertical size shrink a bit and it is most noticeable at the top edge. The width doesn't seem to change. Does that sound like the HV diode is the issue? I don't recall that occurring before but maybe it got disturbed when replacing the caps.
 
If it was HV, it would be shrinking in both directions.

Your pots are probably just dirty. Either on the deflection board, or possibly the game board too. You can wipe them back and forth a few times to try to clean them, but it's better if you do so with DeOxit. (Invest in a can. 15 bucks on eBay. Worth every penny).

That will likely fix it. But if not, you might have a bad pot, or another crack in your deflection board, or possibly a bad transistor (in that order of probability).
 
Thank you for the suggestions and encouragement. I haven't tried adjusting any of the pots yet and it looks like the ones on the monitor still have the blobs of silicon on them to hold them in place.

That would be nice if it is just one of the pots and their adjustment since I may be able to do that without pulling the monitor. I'm sure the could use some adjustment since the whole screen looks like it should shift right a little

I'm going to read back over the manual for it and the X Y monitor guide and should be prepared to try again in the next couple days.

Robert
 
I am going to pull out the monitor and double check all the solder connections again and reflow anything that looks even remotely questionable. Just set a small table next to the game so I can set the monitor on while testing and adjusting if needed to make sure it is solid before bolting it back in. I also ordered a new HV diode to keep on hand since I'll probably need it at some point.

Last night I plugged in a 15v2000 monitor that I have and the vertical shaking doesn't happen on that so it is definitely an issue with the G05 monitor and can focus on that. I noticed that the retrace lines show up on the 15v2000 so I didn't use it too long.

Since the vector monitors are still relatively new to me I'm still not clear on what gets adjusted on the monitors and what gets adjusted on the game board which in my case is the Red Baron. The manual for the Red Baron doesn't really cover adjusting the pots on that board.
 
Check the pots before reflowing anything, as that's the most likely culprit.

As for the adjustments and the retrace lines, that's a monitor adjustment (assuming it's just out of adjustment, and not another issue, as it could be either.)

When I adjust them, I turn the brightness and contrast all the way up, so you can see the retrace lines, and the dots in the center of the objects. Then dial the brightness back until the retrace lines and dots disappear. Then you can scale the contrast back to taste. I usually leave mine all the way up (which makes the vectors fatter, but brighter), but you can dial it back a little if you want a slightly sharper but dimmer picture.

The other pots on the game board and monitor are size (on the game board), and size linearity on the monitor. Use the test mode crosshatch screen to adjust these. The size pots on the game and monitor boards do basically the same thing, but you want the monitor ones dialed back enough such that you can get enough range with the game board pots (i.e., if the monitor is turned up too far, you may not be able to get the screen small enough with the game board pots).

The linearity pots are the trickier ones. These also adjust the size, but only at the edges of the screen, not the middle. These are used to correct the uniformness of the image across the tube. The trick to adjusting these is to make the crosshatch diamonds the same width across the screen, in both the horizontal and vertical directions. Look at the distances from corner to corner of the diamonds, and adjust accordingly. When you get it right, the lines should be pretty straight.

Adjusting linearity can be a little tricky (as it also affects the size as a result), so sometimes it takes a few iterations to get it close, and on some monitors you can't get it 100% perfect, just because everything is analog, including the tube. Patience is a virtue here. But you should be able to get it pretty decent, at least so that the objects don't change size as they move across the screen.
 
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