Sega Master System 50/60Hz Conversion (rev. 0.4 27-Dec-97) ===================================== This document is copyright © 1997 by Mark Knibbs . The latest version, and several other console-related documents, should be available at: http://www.netcomuk.co.uk/~markk/index.html The direct URL for this file is: http://www.netcomuk.co.uk/~markk/Consoles/SMS_50-60Hz_Switch.txt You are explicitly permitted to include the *unmodified* document on web sites, FTP sites and the like. But it is best to simply link to the document on my web page, as this means that you automatically pick up any changes made. If you have any comments, suggestions or questions about this document, please contact me. If you would like to perform a similar modification to your Super NES 16-bit console, you should see: http://www.netcomuk.co.uk/~markk/Consoles/SNES_50-60Hz_Switch.txt The Master System II section of this document could be considered preliminary. Whilst the information given is accurate and I have performed the modification on a Master System II, I do not have access to a Master System II at the time of writing. There are fewer specific details as I am writing from memory, but this should not deter you from carrying out the modification. A similar modification could possibly be done to fit a language switch, but I do not know which pin to use. Can anyone help here? Revision History ---------------- [Starting from rev. 0.3] 0.3 3-Dec-97 Various changes. Updated to cover another Master System I board revision. 0.4 27-Dec-97 Added paragraph about static precautions and step about dissipating stred charge. Various minor changes. Introduction ------------ This document contains information on how to fit a switch to your Master System I or II, to switch between a 50Hz (PAL line standard) and 60Hz display (NTSC line standard). Why might you want to do this? Well, I can think of several reasons: · If you own a PAL or French Master System, you will be familiar with the horrible squashed picture and 17%-too-slow gameplay and music. Almost all games work fine in 60Hz mode, and thus you can play them how the designers intended; full-screen and at full speed. · If you own an NTSC Master System, there are a few foreign games which you will be unable to play. For example, "Back to the Future II" probably contains code to check for a 50Hz frame rate, as it locks up when running at 60Hz. You can switch to 50Hz in order to play games like this. Some other games do work on an NTSC console, but have minor graphical glitches (e.g. "Prince of Persia"). This is probably due to the fact that they were developed in, say, the UK and were not tested on an NTSC console. · Users of NTSC consoles can see exactly how awful the PAL versions of consoles and games released in Europe really are. · NTSC users who find a game particularly difficult or too fast can slow it down to the more sedate PAL speed. Background ---------- Japan and North America are the two main markets for game consoles. Both Japan and the USA/Canada use the NTSC television system. Consoles designed to be played on NTSC TVs show 60 frames (60Hz) per second, each consisting of 262 lines. Europe, Australia and Hong Kong are other markets for game consoles. However, the TV standards used in these countries, PAL and SECAM, show 50 frames per second (50Hz), each consisting of 312 lines. When the console manufacturer gets around to adapting their console for these markets, they usually go the easiest and cheapest route. In order to be compatible with all TVs, they make the PAL version of the console always output a 50Hz picture with 312 lines. This is where the problems occur. PAL consoles show 50 frames per second, as opposed to 60 for NTSC consoles. This means that the gameplay is slowed down by 16 2/3%, or put another way, it should be 20% faster than it is. Unless the game code is adjusted to take account of this (and this is seldom done), PAL gamers are stuck with too-slow gameplay. Another problem results from the different number of lines in the TV picture. Rather than modifying the game console and programs to use the extra 50 lines in the PAL standard, the console is made so that there are large black borders at the top and bottom of the screen. It is rather like watching a "widescreen" film, except the picture is squashed vertically leaving the black borders. This squashing is most noticeable on games which use large circular shapes. These two problems mean that playing games on a PAL console is nowhere near as fun as it should be. The annoying thing is that it would be so easy, and cheap, for the console manufacturer to avoid them, as this modification demonstrates. Most modern TV sets can accept a signal at either 50Hz or 60Hz, automatically sizing the picture so that the image fills the whole screen. However some older sets apparently have problems with this. For example, an old European TV may show a "rolling" picture when a 60Hz signal is input. If the manufacturer were to simply fit a switch allowing the user to choose between 50Hz and 60Hz modes, most people could play games full-screen, at the correct speed. Those with incompatible TVs could still play in 50Hz mode. Since Nintendo did not bother to fit such a switch, you must fit one yourself, and that is what this document is about. Note that the colour standard of the RF and composite video outputs is unaffected by this modification. This means that you will be able to view the 60Hz display on a PAL-only television, and vice versa. The picture output could be called "PAL-60", or "NTSC-50" if you have an NTSC console. Most modern televisions will automatically resize the picture when switching between modes. Some older sets may not like the different frame rate; adjusting the vertical hold control (if present) should solve this. How the Modification Works -------------------------- Depending on whether a certain pin on the Master System graphics chip is held at +5V (Vcc) or 0V (GND), the Master System will output either a 50 or 60Hz picture. [Behaviour can be unreliable if the pin is left unconnected. On my Master System I, the system usually outputs a 60Hz picture, but may revert to 50Hz depending on what is happening in the game.] These modifications simply fit a switch. The common terminal connects to the graphics chip, and the other two to Vcc and GND. So in one position the Master System gives a 60Hz display, and in the other a 50Hz display. You can switch on-the-fly whilst playing a game to see the difference immediately, provided you use a break-before-make type switch. See below. Performing the Modification --------------------------- Whilst the modification is fairly simple, if you have not used a soldering iron before I suggest you ask someone who has some experience with soldering and electronics in general to help you. Maybe your local TV repair person will be willing to do it for you, if you provide a copy of this document, the accompanying picture and a screwdriver for opening the Super NES case. Game consoles, in common with most modern electronic devices are VERY SENSITIVE TO STATIC ELECTRICITY. Ideally, wear a grounding strap and work on a conductive surface when modifying your console. Avoid wearing clothes containing man-made fibres, which are prone to static (e.g. nylon). As far as possible, avoid touching component leads or PCB tracks. Handle the board by its edges. Print out and read this document several times before opening your console. I have successfully carried out the modifications given here on both a Master System I and Master System II. You will need the following: · A SPDT (single pole, double throw) toggle switch, of "break-before-make" type. If it isn't of break-before-make type, you will not be able to switch modes with the console powered on. Most or all toggle switches (silver coloured metal lever) are break-before-make. Some slide switches are not. The switch that I used looks something like this (side view): /\ \ \ Switch lever \ \ \ \ _\_\_ __| |__ | | | | Switch body |___________| | | | Switch terminals · Three lengths of thin insulated wire, long enough to reach from the circuit board to outside the case; 30cm should be sufficient. Using a length of ribbon cable is a good idea, as all the wires are together. · A crosshead screwdriver suitable for removing screws inside the Master System case (a "No. 1" bit should be suitable). · A low power grounded soldering iron with a fine bit and some desoldering braid. · Some solder. · A sharp knife. · A multimeter or continuity checker (useful but not essential). First of all, solder a length of wire to each of the three terminals of the switch. Make sure that you have not accidentally bridged adjacent terminals of the switch with solder. When removing screws, make sure you remember which type goes in which hole! Here are step-by-step instructions: 1. Turn off the console and remove all leads attached to it (AC adapter, controller, A/V lead, etc.). After doing this, turn the power switch on for a couple of seconds and then off again. This dissipates any stored charge inside; you may see the power LED light for a moment as you do this. IT IS *VERY IMPORTANT* THAT YOU DO THIS! YOU RISK DAMAGING YOUR CONSOLE IF YOU DO NOT! 2. Turn the console upside-down, and remove the screws from the base. Turn it back over, and lift off the upper part of the case. Position the console so that it is facing you. From now on, go to the section for your console (Master System I or II). Master System I Modification ---------------------------- The Master System I modification is easier to perform than that for the Master System II. The console PCB has jumper pads to allow selection of the display mode. However, the current setting is 'hard-wired' into the board - there is a trace linking the two appropriate pads on the reverse side of the PCB. You need to cut this trace, remove solder from the pad holes, and insert the switch wires there. 3. Near the centre of the PCB, you should be able to see the jumper pads. They are to the left of a chip labeled: SONY/CXK3864. The silk-screen printing above them reads: ____ NTSC PAL If your Master System I has a later revision board, the jumper pads may be in a different place. However, they should still be marked as above. 4. Remove the PCB from the lower part of the case. To do this, you need to remove the screws which attach the PCB directly to the case (there should be 5 or 6 of them, in addition to the screws which secure the power switch, card slot and cartridge slot. 5. Lift up the PCB and look at the reverse side. You should see that two of the jumper pads are connected by a track on the PCB. Use the knife to carefully cut this track. Make sure that you cut all the way through! If you do not, there will be a short circuit when the switch is in one position. You can use a multimeter or continuity checker to verify that the track is broken. 6. Use your soldering iron and desoldering braid to remove the solder from all three pad holes. 7. Take the switch (which you attached three wires to already), and decide where you are going to mount it. I decided to thread the ribbon cable through the grille on the left-hand side of the upper casing, to avoid having to alter the casing. I tied a loose knot in the cable just inside the casing to prevent damage if the switch was pulled. Solder the middle wire to the middle hole on the PCB. Solder the outer wires to the outer holes. 8. Fix the switch to wherever you want. You could drill a hole in the case or just leave it inside. 9. That's it! Now test your console before fitting it all back together. If you prefer, you could solder some jumper pins to the pads, and move a jumper to switch modes. Master System II Modification ---------------------------- The Master System II modification is harder to perform than that for the Master System I. The Master System II does not have the convenient jumper pads. You need to desolder the appropriate pin of the graphics chip and connect the common terminal of the switch to that. 3. Remove the metal shielding from above the PCB, and remove the PCB from the case. 4. Locate the graphics chip. It's the chip where alternate pins are soldered to the PCB near to and further away from the chip body, giving a 'zig-zag' appearance. On my Master System I (not Master System II), the graphics chip has number 315-5124 printed on it. The graphics chip has 64 pins. Numbers at each corner of the chip should tell you which pin is which. 5. Find pin number 57. Use the desoldering braid to remove most of the solder from the pin. Now you need to lift the pin out of the PCB. You can do this by looping a length of thin wire around the pin, and pulling gently on this while using the soldering iron to melt any remaining solder. 6. Solder the centre (common) terminal of the switch to pin 57, which should now be sticking up, away from the PCB. 7. Pick two locations on the PCB, one which is at +5V (Vcc), and the other at 0V (GND). You can use a through-plated hole, remove the solder in this and scrape the green insulation from the PCB around the hole. Solder the two remaining wires from the switch to the GND and Vcc points. Alternatively, you can solder the wires to the Vcc and GND pins of the graphics chip, which would possibly be easier. 8. Fix the switch to wherever you want. You could drill a hole in the case or just leave it inside. 9. That's it! Now test your console before fitting it all back together. --