Forums The Forum is sponsored by. You are currently viewing the Tips and Deals forum. Newer Topic Older Topic. Posted by: Buzz.
Old Philips CRT horizontal width
I wonder if maybe the 32" got jostled around too much while being moved over the years, or if father time is taking his toll, or if Baby Buzz hooking up ancient video game consoles affected the picture? Sometimes it is what it is Posted by: freeradical. Strong magnets Posted by: Forrest. Posted by: eustacetilley. Well, first get, and then learn how to use, a proper degaussing coil.
There are many "Global" adjustments that can be made to a CRT image, such as focus, pincushion, height and width. But if a certain part of the image just just doesn't fit with the rest, a thorough degaussing is called for. The image rastered on a CRT screen depends on two Sawtooth waveforms, one horizontal, and the other vertical.
The straight sections of the waveforms really need to be straight, and the extremes need to be kept within constraint. There is little that can be done in the way of adjustments if these conditions aren't met. This is an electronic problem that needs an electronic solution, and it probably requires a soldering iron. Some older CRTs have these little rings around the neck, that can be used for used for adjusting for local Earth magnetic field variations.
Don't even touch those rings, unless you are changing hemispheres, and even then, don't even touch those rings.
OK, touch them. They did damn little in any event. Did I mention the bit about not getting shocked? Apple pretty much depends on the fact that displays display what they are meant to display. You are actually given quite a bit of latitude when it comes to Color, and if this interests you, ColorSync has always been your friend.
But as far as geometry goes, you are on your own. Posted by: billb. Posted by: Filliam H. In tha Posted by: Chakravartin. Most CRTs have hidden "service modes" that allow you to make fine adjustments via the remote control.
It only takes a minute to sign up. My CRT all of a sudden is shifted to the right. I cannot adjust it via the adjustment potentiometers, nothing changes when these are turned. If I increase the brightness, the whole screen turns green green monochrome crt. As another user commented, the compact portable has a built-in CRT, so I think they are all the same.
Setup Adjustments For CRT Colour Monitors
I have looked at the service manual, it does go through the steps to calibrate the monitor using the 8 various POTs on the top of the monitor assembly. The vertical adjustment POTs work, but the horizontal ones have no affect on the display at all. The service manual does only goes as far as to mention how to turn these POTs.
It doesn't say what to do if the POTs do not work. I measured the resistance of the POTs, they are all working so I believe there is some control circuitry transistor, capacitor?
I have tried another Video Card on this computer and the same problem occurs Both video cards are for the Compaq portable I with the internal CRT connector. There is no wrap-around on the image, the entire image is shifted to the right and the missing section is missing.
When the computer is put into low-resolution mode the horizontal offset becomes even worse. In low-resolution 40 column mode?
Here is a picture of the adjustments possible. These two adjustments do nothing to the image when turned. I was asked about what happens to the right side of the screen. Well, it appears the image itself gets cut off. Even if I reduce the width as much as possible, the right columns of text are cut off. The issue follows the CRT driver. So I know there is definitely something wrong with the driver board and not with the power supply, video card or tube itself.
The quick answer: C capacitor was bad, replacing it fixed the horizontal offset and now the potentiometers actually adjust the horizontal position. Searched more online and found this similar, but not identical CRT schematic.
It is the same manufacturer and many of the same components. I knew the horizontal adjustment wasn't working, the schematic has documentation that mentions U same on my pcb is used to adjust the horizontal delay which positions the image horizontally. It is a fairly simple circuit, and I knew that the components downstream seemed to work as the image was clear other than this.If you've never adjusted a monitor before, keep in mind there are dangerous voltages inside.
The most obvious is the high voltage on the picture tube, but you're not likely to lift the cap on the CRT during your setup adjustments, so don't worry about that. The not-so-obvious danger is that monitors and TV sets are "line operated" devices.
That means that the chassis is "hot" to ground at all times and poses a lethal potential between chassis parts and other grounded objects around it. Technicians use a isolation transformer to reduce the risk of shock and damage to equipment. You can work in reasonable safety if you keep other grounded objects computer, drives, etc.
Touch only with one hand put the other hand in your pocket, a habit I got into long ago to reduce the risk of electrical shock. Taking a hit from arm to arm across the chest can stop your heart. Now, down to business Advances in technologies along with cost-cutting measures by all electronic equipment manufacturers have produced a display tube that needs less support hardware and fewer setup adjustments than earlier dot-matrix types.Adjusting internal screen control on CRT Television
The most common Cathode-Ray Tube CRT now has three inline side by side electron "guns" rather than the triad arrangement of the earlier types. The newer tubes are sometimes referred to as "slot-mask" or just "inline" CRTs. With inline tubes, the deflection yoke is designed to match the tube so only simple corrections are needed to produce an acceptable picture.
Setup adjustments are done by moving several sets of rings on the neck of the tube. These rings are made of magnetized material to direct the CRT electron beams to the desired locations on the tube face.
The two major alignments are screen "purity" and "static beam convergence". The term "static" simply means beam correction with magnets rather than with electronic circuitry. The latter is usually referred to as "dynamic" convergence and is only used in high-end monitors and large screen TV sets. There are three pairs of rings, each designed for a specific adjustment.
The ones closest to the yoke the large deflection coil assembly, mounted near the bell of the tube are the two pole purity rings. Purity adjustments are necessary only if a blank white screen shows "blotches" of color. The next pair of rings are a four pole type that controls the RED and BLUE static convergence horizontal and vertical lines in the center of the screen.
Behind that pair of rings there is often a locking device. Note: not all makes and model use a locking ring. Mark your own line if there is none. That's useful in case you get "lost" when attempting realignment so you can put them all back in order again. Each ring has two tabs that stick out to allow for adjustment with your fingers, a rounded end and a square end.
The rounded ends are usually pretty close together in normal use and are generally the ones accessible with your fingers. Misconvergence shows up as color "fringing" around the edges of objects anywhere on the screen. The convergence adjustments are normally "roughed in" before purity is adjusted because they interact with each other somewhat.
Unless someone has been "diddling" and has it completely out of alignment, coarse settings will not change and you can just "tweek" the convergence to optimise it. All ring pairs share one thing in common: when the rounded adjustment tabs are set together aligned directly over each otherthe magnetic fields of the two rings cancel each other out.Unfortunately, all monitors and flat-panel displays are different. There is no universal button system or set of instructions we could give you to configure your monitor using the buttons on the front.
By far, the best method of determining what each of the buttons do would be to consult your monitor owner's manual. If you have misplaced your monitor documentation, it can often be found by searching the Internet for the model name or number of the monitor. For general reference, we created the following chart to help illustrate what many of the buttons and icons associated with them do. Below is general information on the likely monitor controls on your monitor.
Using these controls, you can help improve the quality and layout of the picture on your monitor for better viewing. Keep in mind that not all monitors have all of the following buttons.
Furthermore, with many monitors, you need to press a button to access a menu before seeing any of the following options. The names of the monitor icons can differ between brands and types of monitors. If you don't see the exact same icon names, look for icons with names similar to those shown in the chart below.
If the monitor has no more than two buttons on the front of it, is likely configured through software and not with physical buttons. If there are no buttons on the front of the monitor, check on the bottom and top edge.
If no buttons are found, the monitor may utilize touch-sensitive buttons instead of push buttons. Touch-sensitive buttons are often found on the front, bottom edge. Power - Turns the monitor on or off. Brightness - Using this button or wheel the user can increase and decrease the brightness on the screen.
Contrast - Using this button or wheel can increase and decrease the amount of contrast on the screen. Horizontal Size - Allows for the picture on the screen to be stretched to the horizontal edge of the monitor. Vertical Size - Allows the picture on the screen to be stretched to the vertical edges of the monitor.
Horizontal Position - Allows the picture to move moved horizontally. Once in the center, use the Horizontal Size to stretch it to have an equal amount of black border on each side.
Vertical Position - Like the Horizontal Positionusing this button or wheel the user can move the picture up or down to center the picture more appropriately. FullScreen - Sets monitor to fullscreen. Degauss - This button will degauss the CRTrestoring possible color impurities. After this button is pressed, the degaussing circuit will be activated and then deactivated after a few seconds. Pressing and holding this button for a few seconds may cause your computer monitor to reset all data.
Corner and Trapezoid Correction - Using this button or wheel the user can either round the edges of the picture or move the picture inward like an hour glass or outwards.If this is your first visit, be sure to check out the FAQ by clicking the link above.
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Remember Me? What's New? Results 1 to 14 of Thread: Has anyone adjusted a horizontal width coil on an arcade. Thread Tools Show Printable Version. Has anyone adjusted a horizontal width coil on an arcade. Hello, I am still learning the site. I am pretty sure I need to adjust my horizontal width coil. I search the forms and only came up with a post 5 years ago from a member that has not been on since then. Does anyone have experience with this.
Here is a link to some photos. Assuming you have a WG 25k monitor in your cab, it looks like you need to first adjust the horizontal width coil, and the h-pos pot after.
Also make sure the plastic bezel is where it should be, so it's not clipping any picture. Also, sometimes width coils are glued in position.
I've had to use a heat gun to 'loosen' them before. Just becareful with the force you use. If you use a metal allen key while the machine is running you WILL burn yourself. Bob Roberts has parts for many crt's and is a great business to work with! Thanks for everyone's input, I called Radio Shack about getting some TV alignment tools today and I don't know if he did not understand me or what, but he told me they could not get any. I plan on ordering some within the week, after I go look for some in person.
I did have to adjust my brightness and contrast when I bought the machine. I only pray this will be as half as easy. Sorry for posting here, but for some reason I cannot post a new thread even though I am registered I tried to contact the site admin about this. I tried adjusting this on the pots on the pcb underneath the joysticks, but to no avail. I tried adjusting various pots on the monitor chassis itself - it seemed to correct the problem, but once powered down the machine and powered it back on again it went back to the previous state.
It seems to be a grounding issue I looked in the back of the cab for any loose grounds and made sure they were connected, but it still didn't correct the problem. I am not entirely sure what I am doing, so I didn't try to muck around too much in thereRemember Me? Advanced Search.
Forum PressF1 Monitor Horizontal size adjust. How fast is your internet? Test your internet connection. Results 1 to 6 of 6. Thread: Monitor Horizontal size adjust. Thread Tools Show Printable Version. It works fine, except that I can't find the control to expand the horizontal size.
Not quite sure if the gaps were always there when I bought it a few years back. Have tried it on other computers with other video cards, with the same results, the settings are by Pixels. Can't think of any more info that might be helpful. Does anybody remember these old monitors? Perhaps they were made not to be adjusted??? Thanking you all in anticipation Re: Monitor Horizontal size adjust Yes used to have one.
The horizontal width adjustment was on the PC board, one of about 10 unmarked pre-set adjustments. Very difficult to adjust as you need the monitor operating while gutted, which means you take your life in your hands 23, volts on the CRT Also mine would trip the power supply when trying to attain a full scan.
Retrocomputing Stack Exchange is a question and answer site for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear.
It only takes a minute to sign up. My Panasonic CTS12S 20 inches, not 12 inches has some pretty bad geometry in various parts of the screen.
The edges of lines bow in or out, distorting shapes. If the shape is not triangular but curved it can create distortions like you describe. There are few common reasons what could cause it:. You need to identify and change the faulty part. That is usually done by oscilloscope probing specific test points and according to shape of the signal you can decide what is going on.
Some docs for old TVs and Monitors contain this along with the circuitry schematics.
Adjusting The Horizontal Width Coil
Try to look for service manual for your monitor all the info should be there. If you hit the device a bit and situation changes it is the most likely this or cold dead soldering on the PCB.
There are solutions for this. You need to lubricate the part resistive area with something oil-like and not isolative too much. In my region is the best to use this:. Applying a drop of Diava at the trimmer resistive surface and moving the adjustment a bit along the way and then set again to original position will usually help for years then you need to apply it again. Before changing the setting make a mark where it originally was.
The circuitry might got different parameters over time and need a different settings. So you could locate the linearity trimmers and try to adjust them until your lines are linear again. Doing this blindly can do more harm than good. So the best is use an oscilloscope. If You do not have one then use a test screen like:.
If the distribution changes with Y axis on top is different than in the middle then you need to adjust horizontal linearity too. The magnets are used to compensate for Background Earth Magnetism use those only as last resort when nothing else helps. Some tubes also have magnets for focusing do not touch those!!! Do not forget to mark any adjustable parts original position so you can reverse back to original settings!!! As Ralf Kleberhoff pointed out There are high and very high voltages inside your CRT monitor so you need to be extra careful.
Do not touch any metal stuff or parts directly. Use only insulated tools. The most dangerous part is the Voltage multiplier big ugly transformer like but almost without cables part sometimes enclosed by plastics but most likely covered by dark burned dust. It is usually connected with single thick extremely isolated cable to the CRT somewhere on the side closer to the front of the CRT with sucking disc like insulation.
The DC voltages used are usually between Usual air has insulation of 3. Also be careful it tend to suck in also insulators so if you got any free hanging sleeves, hand watches etc it can be a problem.