Polypropylene capacitors are used in most monitor width circuits & changing the value of capacitance up or down on a particular one will effect your pic's horizontal size range that is controlled by the width coil. I will list some of the common chassis "width" cap positions, but you can generally find this cap going to ground off one leg of the width coil itself. As a general ROT these caps will fall in a range from .1uf to .56uf - .1uf being widest & .56uf being narrowest in pic range - and usually at 200 working volts. Note: In some cases this narrow-wider range will be just the opposite due to the surrounding circuitry.
K.... Why do you need to know this? Let's say you just changed out a monitor in a game with another used monitor that you know was working fine in game XYZ, but after you fired it up in it's new home you found that adjusting your width coil from one extreme to the other just would not give you the needed range to either fill the screen, or vice versa, at it's minimum the pic was still so far over the screen that you could not see your "High Score" line :-( (For a player, we all know that is not acceptable :-) The game PCB output is really at fault... well, not a fault necessarily, as it probably filled the pic perfectly on the particular model of monitor that it was shipped from the factory with, but the transplant needs something more & the monitor chassis is the most prudent thing to modify.
I should mention here that the monitor should be recapped, if not recently done, before modifying this circuit to be sure that some electrolytic cap is not at fault for your situation, which would cause it to be even further off the wall at some later point after a recap if you corrected with a polypropylene (PP) cap at this juncture :-(
Note: The width coil does not need to be taken all the way to the top or all the way to the bottom when adjusting. Most width coils have a very short span in which you will go from widest to narrowest range and if pressed will go through a second similar range. When adjusting you should not need to go more than 3 turns in either direction from the starting point. Trying to force this to the top or bottom may cause the ferrite core to crack.
K... As many of you know, I had width cap kits on the Cap Kit Page previously & I found that most did not know what to do with them once they had them, and that the ones that did know, did not like the orange drop PP caps, which are more tubular & cumbersome to work with. I ordered in "brownies" to make up new width cap kits, but have been holding off on posting them until I can get this Page done. Now that you know about this width cap I'll try to answer a few Q's that y'all had & give you a few hints on capacitors & controlling this beast.
The most asked Q was how to read the value as stated on the cap. Sometimes you get lucky & the cap will have the value in microfarads printed on it, e.g., .47, but most times it will be stamped as a three digit number such as 474, whereby you use the first two digits & the third is the multiplier (number of zeros to add)... in this case 470000 & after the demimal point is moved to the left 6 places it becomes .470000 microfarads & after dropping the unneeded zeros it's just plain .47uf ("u" representative of the greek letter mu which means micro, and "f" for farads... capacitor unit of measure.) In case you didn't guess where moving the decimal 6 places came from, micro means one millionth.
Second most asked Q was how to determine the polarity. There is no polarity, so they can be inserted in either direction.
I know I've said I won't get into the technical aspect of things on these pages, but knowing how connecting multiple caps effect their total value can be of use in fine tuning this width circuit, so I will briefly explain how to combine them for new values. Unlike resistors, which add total values together when two are connected in series (end to end chain-like), total capacitance will be the product of the two capacitances divided by their sum. Simplified for this use, suffice it to say that connecting 2 capacitors in series will result in a value less than the smallest value of the 2, so you would be making a smaller microfarad cap by combining the two. How can this help you.... let's say you have 3 caps, a .47uf, a .33uf & a .1uf and you find that the .1uf makes the pic way too wide and subbing in the .33uf just won't make it quite to the edge of the screen, so you need some value in-between. By connecting the .47uf in series with the .33uf cap your end result will be somewhere less than the smallest value which is .33uf, so roughly speaking a .2uf cap. (Well... actual value would be .19 & change :-)
Moving on to connecting caps in parallel & we get a total capacitance equaling the sum of all the individuals, i.e., .47uf joined to a .33uf side-by-side will be .80uf. If you have a width circuit that needs a value of .56uf for optimum pic, combining the .47uf & .1uf in parallel will give you a .57uf well within the 10% margin even if this was a critical cap.
Enough of the half-techie stuff..... hopefully that is clear enough to help you fine tune, but it doesn't hurt to experiment with this circuit, anyway, providing you don't try to wander too far from the original value. Perhaps changing a .1uf with a 1uf & turning the thing into a popcorn machine :-(
Some monitors are width selectable, so be sure to look over the chassis before you leap in. Quite a few of the Asian chassis' will have three values of caps side-by-side with one end of each going to post sticking up from the bd, while across from these three posts will be a wire coming from the bd with a connector on it that slips over the end of one of the posts. Whichever post the wire is on, that cap is in circuit while the other 2 are dormant (I guess this word is "passive" in today's jargon :-), taking up real estate until, or if, needed in the future. I suppose if you were so inclined, you could mount a piece of perf bd on any chassis frame, mount 3 values of caps & extend 2 wires up from the original cap position to make your own width selector. Just food for thought :-)
Trial & error may be the best way for the hobbyist to tune in the width circuit... if need be. For example, if you have a K7000 chassis that has a pic off the screen & cannot be reduced with the width coil and a .15uf cap is installed in C38 position, simply pull the chassis & remove this cap & install a .33uf cap & slip the chassis back in... secure at least 1 screw... and fire it up & take a look at your results. If it's okay, power down & finish up your installation. Needs fine tuning.... pull it out & adjust to your guess for a retry. Since this is not going to be something you do everyday... maybe only once in a lifetime... I think this would be the easiest way.
Here's the common ones I promised:
The contents of the new width cap kit is below & I'll post the kit back to the Cap Kit Page.
Hopefully, this will help solve some of the width problems that quite a few of you have been tinkering with.
Happy Gaming....