RetroHacker
Well-known member
Basic monitor information - how to ask good questions. Read this first
So, you've got a game with a monitor issue. Where to start? Start by finding out some basic information about your monitor, and about your problem. It's very hard for us to be useful when presented with the question "My Ms. Pac has a lousy picture, how do I fix it?". While that may be a valid question, it doesn't have enough information. It's like saying "My blue car won't start".
Things that are very helpful in determining the solution to your problem:
- The kind of monitor you're talking about. There are dozens of different arcade monitors. It's very, very helpful to know which one you need help with.
- The game you're using it in. Some games have different monitor connections than others (positive vs. negative sync, etc).
- What is the monitor doing or not doing? A picture helps here sometimes, but a good description is even better.
How to identify a monitor:
For the most part, raster video game monitors are all pretty much compatible. A monitor from a Ms. Pac will work in Defender will work in Street Fighter, etc. Because of this, it's very common for monitors to have been swapped throughout the life of a game. Not only that, the manufacturer didn't necessarily use the same monitor throughout the entire production run of a game. They used whatever was available and cheapest. So, just because you have an original Robotron or whatever, there's no guarantee that the monitor that's in your original game is the same as what's in mine. The only way to tell is to look at the monitor.
Exceptions to this are Nintendo monitors - those are pretty much always Sanyo 20EZ's. And with vector monitors there are only a couple of types. If you have a vector game, then you've got one of like five monitors.
Look at the back of the monitor. Learn to identify the basic components. The picture tube is the large glass thing that the image is displayed on. This tube is NOT going to be unique to a specific monitor. The numbers on the tube only identify the tube itself, so they aren't helpful in identifying the monitor. The deflection yoke is the coil of copper wire that goes around the neck of the tube. These all physically look very similar - but it's good to know what the yoke is when working on monitors. The chassis is the circuit board that sits beneath the picture tube, and has all the electronics on it. It'll have a flyback transformer - that's the large block with the thick wire coming out of it. That wire connects to the anode of the picture tube with a suction cup. That's the high voltage - don't disconnct this without discharging first, or it'll hurt
. The monitor's frame is usually where you'll find the identifying marks - but sometimes also stuck to the side of a piece of metal on the chassis. It'll say something like Electrohome G07 or WG19K4900 or somesuch. That's the model of the monitor. That's the vital piece of information.
It's not uncommon for these tags to fall off though. So, if you can't find it, there are a couple of ways to identify your monitor. Go to http://www.therealbobroberts.net/monitor.html for a bunch of pictures of monitor chassis. Try to match up what you have. The ones at the top are the most common ones.
Basic monitor gotchas:
DON'T disconnect the HV anode without discharging it first! The picture tube stores a charge, and it can zap you good if you're not careful. To discharge, take a cliplead and attach one end to the monitor's frame, and the other end to the shaft of a plastic-handled flat blade screwdriver. Slide the screwdriver under the suction cup untill you feel it touch the metal contact in the center. If the tube still had a charge, you'll hear a nice POP! You don't need to discharge the tube unless you need to disconnect that anode lead. And watch out, sometimes the tube can sort-of recharge itself, just enough to startle you. Do it again just to be safe.
DON'T connect a monitor directly to a wall socket! Most game monitors are "hot chassis", and as such require an isolation transformer. Plugging such a monitor directly into a household wall socket will fry stuff. This especially includes Nintendo monitors. They have a standard looking wall plug on the cord, but that's meant only for the 100v isolated socket in the bottom of the game.
About screen burn:
Monitor screen burn is a fact of life when it comes to arcade machines. These games were running for many, many hours, and some of them display the same thing most of the time. This leads to screen burn. Basically, a monitor displays an image by drawing an electron beam across the face of a glass tube, the inside of which is painted with colored phosphor. When the beam hits the phosphors, it excites them, and they glow - i.e., they emit their own light. Over time, if the same phospor areas are constantly bombarded with electrons, and constantly glowing, they'll start to wear and darken. They develop a brownish tinge, and emit less light. This area of the screen is now "burnt", and will remain darkened like this forever. You can't unburn a picture tube any more than you can unburn toast. The only way to fix it is to replace the picture tube.
Medium resolution:
Some newer games use what's known as a medium resolution monitor. This monitor has a higher scan rate, and higher screen resolution. Medium resolution games are not compatible with traditional standard resolution monitors, and vice-versa.
Can I use a computer monitor?
Short answer: No. Long answer? Nnnnoooooooo.
The scan rates are incompatible. While converters do exist, the cost of them far exceeds the costs of repairing or replacing the monitor properly, and the picture quality will never be as good as a real arcade monitor.
What about LCD's?
They do make arcade resolution compatible LCD's. They're very expensive, and don't look as good as a real monitor. Similarly, there do exist converters to convert arcade video to VGA - they're also very expensive, and it'll look like garbage. Also, putting an LCD in an 80's arcade game is considered a sacralige, much like cutting up a 1957 Chevy to shoehorn a modern engine into. And once you've seen a game so converted, you'll understand exactly why people feel that way. It looks terrible.
Hopefully this helps you understand a little about game monitors, and enables you to ask helpful questions. We're always happy to help and answer questions... but hearing the same thing a hundred times gets a bit old. Once you know your monitor's model, you can always search this forum for more information on your problem.
I'll also be adding to this thread, with basic problems and terminology explained.
-Ian
So, you've got a game with a monitor issue. Where to start? Start by finding out some basic information about your monitor, and about your problem. It's very hard for us to be useful when presented with the question "My Ms. Pac has a lousy picture, how do I fix it?". While that may be a valid question, it doesn't have enough information. It's like saying "My blue car won't start".
Things that are very helpful in determining the solution to your problem:
- The kind of monitor you're talking about. There are dozens of different arcade monitors. It's very, very helpful to know which one you need help with.
- The game you're using it in. Some games have different monitor connections than others (positive vs. negative sync, etc).
- What is the monitor doing or not doing? A picture helps here sometimes, but a good description is even better.
How to identify a monitor:
For the most part, raster video game monitors are all pretty much compatible. A monitor from a Ms. Pac will work in Defender will work in Street Fighter, etc. Because of this, it's very common for monitors to have been swapped throughout the life of a game. Not only that, the manufacturer didn't necessarily use the same monitor throughout the entire production run of a game. They used whatever was available and cheapest. So, just because you have an original Robotron or whatever, there's no guarantee that the monitor that's in your original game is the same as what's in mine. The only way to tell is to look at the monitor.
Exceptions to this are Nintendo monitors - those are pretty much always Sanyo 20EZ's. And with vector monitors there are only a couple of types. If you have a vector game, then you've got one of like five monitors.
Look at the back of the monitor. Learn to identify the basic components. The picture tube is the large glass thing that the image is displayed on. This tube is NOT going to be unique to a specific monitor. The numbers on the tube only identify the tube itself, so they aren't helpful in identifying the monitor. The deflection yoke is the coil of copper wire that goes around the neck of the tube. These all physically look very similar - but it's good to know what the yoke is when working on monitors. The chassis is the circuit board that sits beneath the picture tube, and has all the electronics on it. It'll have a flyback transformer - that's the large block with the thick wire coming out of it. That wire connects to the anode of the picture tube with a suction cup. That's the high voltage - don't disconnct this without discharging first, or it'll hurt
It's not uncommon for these tags to fall off though. So, if you can't find it, there are a couple of ways to identify your monitor. Go to http://www.therealbobroberts.net/monitor.html for a bunch of pictures of monitor chassis. Try to match up what you have. The ones at the top are the most common ones.
Basic monitor gotchas:
DON'T disconnect the HV anode without discharging it first! The picture tube stores a charge, and it can zap you good if you're not careful. To discharge, take a cliplead and attach one end to the monitor's frame, and the other end to the shaft of a plastic-handled flat blade screwdriver. Slide the screwdriver under the suction cup untill you feel it touch the metal contact in the center. If the tube still had a charge, you'll hear a nice POP! You don't need to discharge the tube unless you need to disconnect that anode lead. And watch out, sometimes the tube can sort-of recharge itself, just enough to startle you. Do it again just to be safe.
DON'T connect a monitor directly to a wall socket! Most game monitors are "hot chassis", and as such require an isolation transformer. Plugging such a monitor directly into a household wall socket will fry stuff. This especially includes Nintendo monitors. They have a standard looking wall plug on the cord, but that's meant only for the 100v isolated socket in the bottom of the game.
About screen burn:
Monitor screen burn is a fact of life when it comes to arcade machines. These games were running for many, many hours, and some of them display the same thing most of the time. This leads to screen burn. Basically, a monitor displays an image by drawing an electron beam across the face of a glass tube, the inside of which is painted with colored phosphor. When the beam hits the phosphors, it excites them, and they glow - i.e., they emit their own light. Over time, if the same phospor areas are constantly bombarded with electrons, and constantly glowing, they'll start to wear and darken. They develop a brownish tinge, and emit less light. This area of the screen is now "burnt", and will remain darkened like this forever. You can't unburn a picture tube any more than you can unburn toast. The only way to fix it is to replace the picture tube.
Medium resolution:
Some newer games use what's known as a medium resolution monitor. This monitor has a higher scan rate, and higher screen resolution. Medium resolution games are not compatible with traditional standard resolution monitors, and vice-versa.
Can I use a computer monitor?
Short answer: No. Long answer? Nnnnoooooooo.
The scan rates are incompatible. While converters do exist, the cost of them far exceeds the costs of repairing or replacing the monitor properly, and the picture quality will never be as good as a real arcade monitor.
What about LCD's?
They do make arcade resolution compatible LCD's. They're very expensive, and don't look as good as a real monitor. Similarly, there do exist converters to convert arcade video to VGA - they're also very expensive, and it'll look like garbage. Also, putting an LCD in an 80's arcade game is considered a sacralige, much like cutting up a 1957 Chevy to shoehorn a modern engine into. And once you've seen a game so converted, you'll understand exactly why people feel that way. It looks terrible.
Hopefully this helps you understand a little about game monitors, and enables you to ask helpful questions. We're always happy to help and answer questions... but hearing the same thing a hundred times gets a bit old. Once you know your monitor's model, you can always search this forum for more information on your problem.
I'll also be adding to this thread, with basic problems and terminology explained.
-Ian
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