Conference hydra::amiga_v1

4192.0. "NTSC / PAL mode switch for A2000" by BOMBE::MOORE (Amiga: Real computing on a PC budget) Fri Oct 12 1990 00:15

Article 15283 of comp.sys.amiga.tech:
Path: shlump.nac.dec.com!bacchus.pa.dec.com!decwrl!uunet!timbuk!cs.umn.edu!kksys!orbit!pnet51!koleman
From: [email protected] (Kurt Koller)
Newsgroups: comp.sys.amiga.tech
Subject: Re: NTSC on a PAL Amiga
Message-ID: <[email protected]>
Date: 10 Oct 90 20:05:02 GMT
Sender: [email protected]
Organization: People-Net [pnet51], Minneapolis, MN.
Lines: 71

Here is a PAL/NTSC switch setup I developed for those machines with a BIG FAT
AGNUS...
 
          How to install the NSTC / PAL switch into your Amiga 2000
         ===========================================================
 
 
 
         This modificiation will work on a default NTSC or PAL A2000.
 
      First off take the cover off your machine and remove the drive and
      Power supply chassis ( disconnect the power supply and the disk
      drive ribbon cable from the motherboard...make sure you remember
      which end of the cable goes to which pins!!! ). Then remove the
      whole unit from the machine and set it aside...
 
  
  
        A. Now look for the FAT AGNUS chip on the motherboard, it should
           say FAT LADY near the chip....now check the number on top of 
           the chip, You MUST have the new 1 Meg Agnus (Super Agnus part
           #8372).
   
        B. Move motherboard jumper J300 from the factory default position
           of pins 1-2 to pins 2-3. This jumper is located under the power
           supply.
  
        C. Locate jumper PADS (no pins) labeled J102 and cut a trace
           between the 2 pads.  BE CAREFUL!! The pads are located right
           next to the AGNUS on the left hand side ( if you are PAL 
           default no need to cut the trace..since PAL is already cut)
  
        D. Mount a SPST switch in a convient place on the outside of the
           Amiga, perhaps next to the power on LED.
  
        E. Run 2 wires from the switch to the 2 pads of J102 (1 wire to
           each pad).
  
      That's it.  With the switch closed (on position), you'll boot in
      NTSC.  With the switch in the open position (off), you'll boot in
      PAL.
  
      NOTE: Most monitors will only require a minor adjustment in vertical
      sync and/or size to work in this manner.  Composite monitors will 
      NOT work.
  
      You must re-boot for the change to take effect, since the jumper
      is only checked at power-up.  If you have problems with Genlocks
      that go in the video slot, run a SPDT switch to the J300 jumper
      to allow you to switch timing between Power supply and Video
      section sources.
 
 
                     Call my BBS - Alt-3 - (612) 228-0127
                                   Koleman
 
 
My BBS is down.  Sorry, I don't feel like editing.
 
You do not need to change the J300 jumper, it's just that if you don't, SI
will report 50hz video, PAL, but 60hz power supply.  IF you have J300 changed,
it reports 50hz on both (true PAL), however you don't REALLY run at 50hz, you
just pretend...
 
There is also a bug in the OS which causes the opening screen to be NTSC
dimesnions on a PAL display, but this doesn't happen all that much.  If you
leave your opening window open (it still is 640x200, not to be confused with
opening screen, 640x256) there is a program I wrote that will change it for
you.  I would FTP it or whatever, but I don't know how!

Kurt "Koleman" Koller - amdahl!bungia!orbit!pnet51!koleman

    I have an NTSC Amiga 500 in the UK (ie NTSC crystal oscillator), can 
    anyone suggest a similar NTSC/PAL switch for the lowly A500.
    
    WILLY PITCAIRN

    I've installed a switch in my 2000, as described in .0, it works very
    well.
    
    re: .1
    According to the A2000 schematics, J102 feeds a pin on Agnus marked as
    "TEST".  It is grounded for NTSC mode, pulled high for PAL.  Maybe you
    can locate a similar jumper on the A500 diagrams.  I believe you must
    have the 1Meg Agnus chip for this to work.

    
    I also applied this to my 2000 and it works OK.  There is the same
    signal on the 500 Agnus pin 41 (page F3) but it does not have a labeled 
    jumper pad.  If there is a visable etch you might be able to cut it. 
    My 500 has the old chip so I will not have the oportunity to try it
    myself.  If you do be careful, it will void your waranty.
    
    Alan