There is a very simple way of doing that. I though you all knew that, and didn't want to be redundant, but here we go: - For mac portrait displays, I don't know. But I always had run tubes on vertical on...ARCADE MACHINES! :D There is no problem on running B/W or colour tubes on vertical, trust me. - Tube swap is very simple. You can assume that if the neck connector fits, it will work. There are not many different tubes around, the problem is the yoke. On B/W tubes you just take the yoke of the fried tube off and put that on the new. No special alignment/convergence procedure necessary. Just line up the text on screen moving the yoke cw/ccw and you are set. For colour tubes, there are differences, here we go. - There are mainly three types of colour tubes: Mini-neck (the neck is the diameter of a fat finger), Low focus and High focus. Of course, I'm talking about inline masks. That Delta tubes (the RGB triad is a delta of points, instead of three lines one besides other) I've never seen that used in anything beyond televisions. If you have a monitor using a delta mask tube, forget it! The adjustments you're going to do are too difficult even to a profissional. - Low focus and High focus: You can see what kind is, looking at the tube socket or the neck end of the tube. The high focus tube has a plastic ring inserted on the pins, with a pin isolated from all the others. You can see the same in the socket. Low focus doesn't have that, the end of the tube has only pins, no plastic separator. - If you change colour tubes (talking about high focus and low focus), usually it is just a matter of changing the tube and using the same deflection set (yoke, convergence rings et al). E.G.: You have a monitor like the Amiga 1084/S which uses a philips or samsung tube, Low focus type, 15KHz yoke. Just buy any (!) television with the same chacarteristics (low focus) and change it. Yes, you can use the same yoke. Almost always the paramenters of the yoke are **the same**. The same happens for VGA monitors. Usually, all vga monitors uses the same type of yokes. YMMV, but this is the rule here. Please note: Yokes of 15 KHz monitors and 31 KHz monitors (vga and above) are NOT intechangeable. But the tubes ARE! - If you need to change the tube of, as an example, an EGA monitor, you'll not find a complete set from a television of from an old vga monitor, you'll have to change only the tube, keeping the deflection parts (yoke, convergence ring) and will have to do all the convergence procedure yourself. It is boring, it is hard, it is boring. But if you have no way to find a suitable replacement tube, there you are. Ok, too much words, here we go for a simple list: - If you have a B/W monitor, you can change the tube for ANY tube with the same neck size and that fits phisically in place. Keep the yoke from the old tube and put it on the new. You'll be only changing the glass tube. - If you have a COLOUR monitor, if the pixels are inline (sets of three bars, RGB on screen), you can change for any tube of the SAME type, paying attention if it is low focus or high focus. You can go some sizes above and beyond. E.G: A 14" monitor can use a 17" or even a 20" tube, the reverse is true. - If you have a VGA or HIGHER frequency monitor, you need a tube with yoke from a monitor of SIMILAR frequencies. Same as above - If you have a 15 KHz monitor and only have a VGA tube, and vice-versa, you can change THE TUBE, but will have to change the deflection set (yoke/convergence rings) and do all the convergence procedure yourself. Samsung manuals are great for teaching that, get the Syncmaster III service manual and be free. Any questions, feel free to write me Greetings from Brazil, Alexandre Souza www.tabajara-labs.com.br