A complete guide (text and pictures) of all the A1200 motherboard modifications.
It includes the timing fixes and wire mods done to some later 2B motherboards.

http://www.ianstedman.co.uk

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
-rw-rw-rw-     0/0      858443  858443 100.0% -lh0- b7f0 Nov  9  2003 A1200-timingfix.jpg
-rw-rw-rw-     0/0        4277    4434  96.5% -lh5- 38be Nov 26  2003 a1200moboR118_tn.jpeg
-rw-rw-rw-     0/0        3778    3927  96.2% -lh5- 9439 Nov 26  2003 clock-paula_tn.jpeg
-rw-rw-rw-     0/0       49906   49980  99.9% -lh5- 29d5 Nov 26  2003 a1200moboR118.jpeg
-rw-rw-rw-     0/0      161988  161988 100.0% -lh0- 8324 Nov 17  2003 clock-paula.jpeg
-rw-rw-rw-     0/0        4293   15047  28.5% -lh5- ce59 Nov 28  2003 a1200_mobo_fix.html
-rw-rw-rw-     0/0        3394    3543  95.8% -lh5- 0449 Nov 26  2003 cia_tn.jpeg
-rw-rw-rw-     0/0      110310  110312 100.0% -lh5- f2ec Nov 17  2003 cia.jpeg
-rw-rw-rw-     0/0        3861    4010  96.3% -lh5- 1160 Nov 26  2003 next_to_roms_tn.jpeg
-rw-rw-rw-     0/0      148042  148106 100.0% -lh5- df51 Nov 17  2003 next_to_roms.jpeg
-rw-rw-rw-     0/0        6718    6871  97.8% -lh5- 0ff3 Nov 26  2003 A1200-timingfix_tn.jpg
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        11 files 1355010 1366661  99.1%            Nov 29  2003