Switch Modification

              Super NES/Super Famicom 50/60Hz Switch Modification
                             (rev. 0.4 25-Jan-98)

This document is copyright © 1997-1998 by Mark Knibbs <mark_k@iname.com>. The
latest version, and several other console-related documents, should be
available from my web page:
The direct URL for this file is:

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.

Please contact me if you have any comments, suggestions or questions about this

Revision History
 0.1   21-Dec-97   First release.
 0.2   26-Dec-97   Added note about static electricity. Emphasised necessity of
                   dissipating stored charge before opening console. Other
                   minor changes.
 0.3   27-Dec-97   Minor changes.
 0.4   25-Jan-98   Added that you should connect a 2.2kOhm resistor between the
                   regulator Vcc terminal and the switch.
                   Added pointer to digitised pictures of a modified console.

This document describes how to add a switch to your Super NES or Super Famicom
video game console in order to switch between 50Hz (PAL line standard) and 60Hz
(NTSC line standard) display modes.

Why might you want to do this? Well, I can think of several reasons:

· If you own a PAL Super NES, you will be familiar with the horrible squashed
  picture and 17%-too-slow gameplay. Almost all games work fine in 60Hz mode,
  and thus you can play them how the designers intended; full-screen and at
  full speed.

· Most later Super NES games contain code that checks for a 50Hz or 60Hz
  display, and refuses to work if it find the "wrong" one. For example, the US
  version of "Super Mario All-Stars" refuses to work on a PAL SNES, and PAL
  Super Metroid refuses to work on an NTSC SNES. By fitting a switch and
  setting the correct mode, you can play games like this. Since most games only
  do the check right at the start, you can switch to 60Hz mode when playing the
  game. This allows most PAL games to be played full-screen.

· 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.

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

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. Also,
some games have small borders even on NTSC consoles. On PAL consoles, these
borders become very large indeed.

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.

Because of the different lockout chips, to be able to play any PAL games on an
NTSC console or vice versa, you need to disable the lockout chip inside your
console. It is a good idea to do this at the same time as you add a 50/60Hz
switch. For instructions on how to disable the lockout chip, see:

Alternatively, "universal adapters" are widely available, at least in Europe.
These have two connectors. In one you put the foreign game to be played, and in
the other a domestic game. The lockout-related lines are routed from the
domestic cartridge, thus fooling the console into playing the foreign game.

By disabling the lockout chip and fitting a 50/60Hz switch, you should be able
to play almost any Super NES or Super Famicom game on your console, regardless
of the country of origin. Even counterfeit games which have no lockout chip
inside should work. Note that you will need an extension adapter to use US
cartridges with a PAL Super NES or Japanese Super Famicom, due to the different
shape of cartridge opening used. If you remove the plastic tabs from behind the
cartridge slot in a US Super NES, you can play Japanese and PAL games directly.

How the Modification Works
Inside the Super NES there are two graphics chips, called PPU1 and PPU2; PPU is
short for "Picture Processing Unit". These are responsible for creating the
Super NES graphics.

Back in the days of the 8-bit NES, PAL and NTSC NES consoles used different
graphics chips, so it is not possible to fit a 50/60Hz switch to a NES. Luckily
Nintendo changed this scheme for the Super NES. Both PAL and NTSC consoles use
exactly the same PPU1 and PPU2 chips. Whether the console outputs a 50Hz or
60Hz picture is determined by what voltage a certain pin of each chip is at.
The circuit boards of PAL and NTSC consoles differ slightly here.

This pin, termed "PALMODE", is held at 0V for NTSC consoles, and +5V for PAL
consoles. What the modification does is to disconnect the two PALMODE pins
from the circuit board, and wire up a switch so that in one position the
PALMODE pins are at 0V (giving a 60Hz display, the default for NTSC consoles),
and in the other the PALMODE pins are at +5V (giving a 50Hz display, the
default for PAL consoles).

You can switch between 50Hz and 60Hz modes at any time, even when the console
is on.

The procedure given here should work for any Super NES or Super Famicom.
However, I have not seen the new model US Super NES. If you fit a switch to one
of these, please let me know, and tell me if there are any differences.

If you perform this procedure on your console, PLEASE LET ME KNOW WHETHER IT
WORKS! I want to update this document so that it's applicable to as many
consoles as possible. Please tell me which PCB revision your console has (e.g.
SHVC-CPU-01, SNS-CPU-GPM-01) and its serial number.

I have successfully carried out this procedure on a U.K. model Super NES, and
do not anticipate any problems with performing it on any Super Famicom or Super
NES console.

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.
There is a picture to accompany this file; I suggest you view this before
opening the console. The URL is:

There are also some digitised pictures of a modified console. You can find
these at:

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
· Four 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 2.2kOhm (i.e., 2200 ohms) resistor

· Some insulating tape is advisable.

· A screwdriver suitable for opening the Super NES case. The screws are special
  tamperproof screws, referred to as "System Zero" or "Line Head System". A
  suitable screwdriver can be obtained from a company called MCM Electronics in
  the USA (http://www.mcmelectronics.com/) or from RS Components in the UK.

· A crosshead screwdriver suitable for removing some screws inside the Super
  NES (a "No. 1" bit should be suitable).

· A low power grounded soldering iron with a fine bit and some desoldering

· A multimeter or continuity checker (useful but not essential).

· A thin needle or similar implement.

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

 2. Turn the console upside-down, and remove the six 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.

 3. Remove the eject lever. Pull up the right-hand side of the metal rod and
    slide it out, then remove the lever and spring.

 4. Remove the two screws which secure the power switch to the casing. Lift up
    the switch so that you can get at the screw below.

 5. Gently remove the ribbon cable which leads to the controller socket PCB
    from the connector at the front of the PCB.

    You do not need to do this if you have a late revision console. You can
    identify this by the fact that there are only two screws holding down the
    shielding, and you can see that the ribbon cable does not interfere with
    removal of the shielding.

 6. Now unscrew the metal shielding from in front of the cartridge slot. The
    exact details of this step depend on which revision PCB your console has. I
    will give specifics for the three variants that are known to me.

    · For early consoles, which can be identified by the separate plug-in sound
      module "SHVC-SOUND", there are six screws to remove from the shielding,
      including the two which are on either side of the cartridge slot. (After
      removing the shielding, you may see "SHVC-CPU-01" printed on the PCB if
      you have a U.S. or Japanese console.)

    · For later consoles, which have no separate sound module, there are four
      screws to remove. (You may see "SNSP-CPU-02" printed on the PCB after
      removing the shielding for a PAL console.)

    · For still later consoles, there are two screws to remove. There is no
      need to remove the controller ribbon cable. (You may see "SNS-CPU-GPM-01"
      printed on the PCB after removing the shielding for a U.S. model

 7. Carefully lift up the metal shielding. The edges may be quite sharp. You
    will see various chips. Locate the PPU1 and PPU2 chips. These are two of
    the largest chips on the board, so you should find them easily. They are in
    front of the game pak connector. PPU2 is nearest the connector, and PPU1 is
    in front of PPU2.

 8. Now you need to find the PALMODE pin on each of PPU1 and PPU2. In both
    cases, the PALMODE pin is one of the pins on the left-hand edge (the edge
    nearest the power switch). There are pin numbers printed on the PCB next to
    both ends of each edge of the PPU chips. Refer to the accompanying picture.

    For PPU1, the pin is the seventh along from the one at the end nearest to
    you. It is pin #24.

    For PPU2, the pin is the one at the end nearest to you. It is pin #30.

 9. Both PALMODE pins need to be removed from the PCB and carefully bent up, so
    that wires from the switch can be attached to them. Make ABSOLUTELY SURE
    that you are working with the correct pins!

    Use the desoldering braid and soldering iron to remove some of the solder
    from each pin. It may help to cut the end of the braid into a "V" shape, so
    that you don't inadvertently desolder any adjacent pins. Position the end
    of the braid over where the pin meets the PCB, and briefly press down on
    this with the soldering iron bit. You should see that some solder has been
    "sucked into" the braid.

    Using the needle, apply a gentle levering action to the pin as you
    momentarily touch the soldering iron to it. The pin should come away from
    the PCB. Carefully pull it up using the tip of the needle as a lever, so
    that the end is a couple of millimetres away from the PCB.

    When you have done this for both pins, cut a length of insulating tape and
    lay it on the PCB, to the left of the PPU chips. Doing this will reduce the
    likelihood of damage occuring when you do the soldering later on.

10. Now is a good time to attach the wires to the switch. I'll assume that you
    are using a length of ribbon cable with four wires here.

    Firstly, make sure you have a long enough piece of cable. At least enough
    to go from the PPU chips to outside the case, with some to spare.

    Separate the four wires at one end of the ribbon cable, and strip a few
    millimetres of insulation from each of the four. Twist the ends of the two middle
    conductors together, and tin all three exposed ends (dip them in a blob of
    molten solder on the soldering iron). This stops strands coming away from
    each conductor.

    Take the SPDT switch and solder the middle two wires of the ribbon cable
    (which should now be joined together at the end) to the middle terminal of
    the switch. Solder each of the outer two wires to each of the remaining
    two switch terminals. Make sure that there are no short circuits. If
    necessary use some insulating tape or heat-shrink tubing to insulate the
    switch terminals after soldering the wires.

    Now decide where you want the switch to go. I suggest passing the ribbon
    cable through the grille at the back of the case. Doing it this way you do
    not need to modify the case at all. Tie a loose knot in the cable just
    inside the case, to prevent damage if someone were to accidentally pull on
    the switch. Alternatively you could drill a hole in the case, and mount the
    switch through there.

    Separate the four wires at the free end of the ribbon cable. 15 or so
    centimetres should be enough. Strip and tin each end.

11. Locate the 7805 voltage regulator. This is fixed to the left-hand side of
    the metal heat-sink (the large metal part that lies above the rear half of
    the PCB). It has three pins, marked I, G and O. You are interested in the G
    and O pins. G (for ground) is at 0V, and O (for out) is at +5V. G is the
    middle pin, and O is the pin nearest the front of the console.

    Solder one of the outer conductors of the ribbon cable to the G pin of the
    7805 regulator. It will help if you bend the end of the wire into a small
    hook shape before doing this.
    Take the 2.2kOhm resistor, and solder the other outer conductor of the
    ribbon cable to one end of it. Solder the free end of the resistor to the O
    pin of the regulator. Use some insulating tape or heat shrink tubing to
    ensure that there is no possibility of the resistor leads causing a short

    Inspect the joints to check that there is no short circuit between the G
    and O pins. Use a multimeter to check this if necessary.

12. Now you need to solder each of the two middle conductors of the ribbon
    cable to one of the PALMODE pins which you bent up from the PCB earlier. As
    with the other wires, it helps to bend the ends into a small hook shape.
    Make sure that you don't accidentally short out adjacent pins of the PPU
    chips by e.g. dropping a blob of molten solder on them.

    It is important that the wires which are now attached to the PPU PALMODE
    pins do not put any strain on the pins. Arranging them so that there is
    some slack, you can stick the ribbon cable to a bare spot on the PCB with
    insulating tape to ensure that the cable cannot move about and thus pull
    at the pins.

13. Almost there. Check again that you haven't inadvertently created any short
    circuits during soldering. It is a good idea to test the console before
    putting it back together.

    Rest the power switch on its mounting and connect the AC adapter,
    controller, video lead and a game pak. Switch the console on. If all has
    gone well, the display should appear, in either 50Hz or 60Hz mode depending
    on how the switch is set. Flip the switch and notice how the display
    changes. Play a game and see the speed difference. Turn the console off and
    remove all attachments (AC adapter, etc.). Turn the power switch on and
    then off as in step 1.

14. Put the console back together. The procedure is the reverse of steps 2 to 7
    above. You may find fitting the eject lever tricky. If so, put the metal
    rod through the lever, and put the spring on the left end of this, so that
    the outwards-pointing end of the spring is downwards. The outwards-pointing
    end should be the longer of the two. Ease the spring and lever into
    position, ensuring that the end of the spring goes into the recess in the
    casing. Now carefully move the other end of the spring back until it is in
    the recess in the lever.

Thanks to:
· Rowan for drawing the original picture that illustrated this modification.
· Karel Pauwels for pointing out the need for a resistor between Vcc and the
· H. Meun for creating and sending me the digitised pictures of his modified


Version original en texte brut : snes-50-60hz-switch.txt

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