 This is the Sony PVM-20M4U Trinitron CRT monitor. It boasts a 19-inch display screen area and has an increased line resolution over the other M-Series PVMs. The normal PVM would have 600 lines of resolution. This one has been increased up to 800 lines of resolution. It is one of the most desirable PVMs simply because the higher line count on the tube provides a crisper look You will notice more defined scan lines on this monitor. Now it is important to note that this monitor only supports 240p and 480i video resolutions. It will not support any 480p or higher resolutions or any digital video resolutions. It does accept NTSC and PAL in the form of composite component S-Video and then there's RGB and sync support with an optional card for a BKM-101C to add support for SDI. It has convenient controls on the front for a quick changing of inputs and screen settings and it does feature an on-screen menu that will allow for geometry and color adjustments. In the back of the 20M4U you will notice some hardware changes that are not the same in the other M-Series that being the M2 or any of the other ST or medical models that you may have. This CRT has a specific yoke for it that allows for more controls. I'll show you a closer look at it. But it has three potentiometers in the top that do allow for some convergence adjustments as well as your normal convergence adjustments over here and purity with your rings on your deflection yoke. But then you've got a separation here on the neck of the tube and then a second screwed in convergence adjustment here. So that's separated a little bit and that is a little bit of a design change from any other M-Series. I'll let you see a little bit closer on the yoke in here and that means that the build out is slightly different on our neck board and also on our main deflection board for this monitor. Take a closer look here. Those are your three adjustment potentiometers that you can use and you'll want to use some kind of convergence pattern in the 240P test suite and even the monoscope pattern on there by Keith Rainey is really good to use for this and you can adjust those and that will help with your convergence. And then as I said before the neck board is slightly different than the other M-Series, the C-Board. So that's something to note. It's not hugely different but just a little bit different. Same thing with the build out on the main board. That does have a little bit different build out but it will be the same printed circuit board used for this and the M-Series. It's pretty much the same. Now the one thing that you do need to note on the M4 is that if we look closely here at our input board we do not get the same, we do not get that same extra input for RGB and component. You do have a switchable line down here for RGB and sync or component. And this was a trick that I actually learned recently but if you're not going to daisy chain out your audio especially on something like RGB and you just want to have it Y connected these PVMs have built in Y connectors so you can just put your stereo speakers on the in and the out and it will automatically detect that and pump your audio through mono into your speakers so you don't have to buy the little Y connector and put it in the in. You can actually just use it how it's set up here and test that and make sure I'm right on there but from what I've been using the last few days it's been working perfectly and then that again is switchable to component. You've got a line C here for S-Video in and out and then two composite video in and out lines with mono audio also and a remote plug with some remote controls if you want to run an external remote. Here's a little bit closer. Look at this section of the tube right here where we have our normally our convergence rings will be set up and pretty much sequence usually you'd see all three of them together against the back of the yoke right here but as I said we've got a little bit of a separator between these two that's not normally there on the other M series and then we've got this separation right here where we have an extra plastic ring first and then we've got our convergence ring up front here so that's just just be mindful of that the convergence is a little bit different on this one. Let's go over some final details here on the Sony PVM-20M4U. First off if you're lucky enough to find one of these it's definitely a good idea to try to get them checked out or serviced as we sit here in the year of 2021. These are pushing towards 20 to 25 years old on average and that means that the capacitors in different areas can be stressed and can be worn out especially in those deflection areas and there was even a few capacitors that are involved in a red-green-blue line issue that can appear on this in any other M series monitor and that has to do with a couple of capacitors that tend to fail and they are in a deflection block so there's at least 15 caps that you should be mindful of to change on this monitor and you can even change a few more. So that's something you need to think about if you're going to invest or get one of these 20M4Us. You should also note that they are quite expensive for one that is working right now and that would mean I would estimate a price tag in the neighborhood of $1,500 up to $1,800 for one that's just certified working and works well and doesn't need a whole lot of servicing but then if you get it serviced you could push the value on one of these to over $2,000 if the tube is very bright it's in great condition I could easily see a $2,000 price tag on one of these this year and that's US dollars but that's pretty much what you need to know about this 20M4U at least to get you started if you're just interested in learning about the monitor itself. 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