MSX2(+) upgrades – MSX Info Pages

MSX 2(+) conversion

Convert to MSX2+ by replacing the V9938 with a V9958 and add the F4 register required by Basic 3.0

pdf Build a v9958 into a NMS8250/55
pdf Build a v9958 into a NMS8280
pdf Build a v9958 into a HB-700
pdf Add the F4 register

Notes by JP Grobler on converting his NMS8250 to a MSX 2+:(with lots of help by Hans Oranje)
I got the v9958 vdp and had the v9938 removed & replaced with a shrinked dip socket at a TV repair shop (2Euro)

On the v9958 (connections were done on the chip itself!):

Pins 1, 4, 27 GND
Pins 21, 58 +5V Capacitor 100nF between pin 21 and pin 20 (Analog GND).
I only had 27512 eproms and burned Basic 3 + Bios Sub roms into it.
On the 8250:
IC 119 = Main rom
IC 118 = Subrom
IC 117 = Diskrom
I only replaced IC 119 & IC 118
IC 118 socket:
Pin 1 (A15) is connected to +5V
Pin 27 (A14) is connected to +5V
Do not connect these pins of the eprom to the socket!
Add wire between Pin 1 (A15) and the unused
slot connector (MY) Pin 42 (5th from right)
Add wire between Pin 27 (A14) and the unused
slot connector (MY) Pin 41 (5th from right)
IC 119 socket:
Pin 1 (A15) is connected to +5V
Do not connect these pins of the eprom to the socket!
Add wire between Pin 1 (A15) and Pin 16 (GND)
Add the F4 latch: see Hans Oranje instructions

The source of these instructions is Hans Oranje!
These ROMS are published here with permission from Hans Oranje.
pdf ROMS used by JP Grobler for MSX 2+ Basic 3.0

Hans Oranje not only adapted the MSX2+ ROMS to the international standard as used in dutch MSX machines, he also adapted for german MSX machines (for example keyboard mapping).
pdf German MSX BASIC V 3.0 ROMS made for Franz Schiefer Austria and used in the NMS8280
Complete according to the SONY Technical Databoek

Thanks to Jipe, ROMs for VG8235 MSX2+ + No F4 port (triggered by Giorgio Sagias):
pdf VG8235-19 MSX2+ ROMS (Jipe, AZERTY keyboard layout)

pdf VG8235 MSX2+ ROMS (Jipe, QWERTY keyboard layout)

Dutch article how to perform the MSX2+ conversion
pdf MSX2+ conversion

The instructions to convert the SVI 738 to MSX-2 also in english, combined the CUC dutch (translated) info and the danish/finnish info
pdf Convert the SVI 738 to MSX-2

pdf A patched extended ROM for the SVI 738 or MSX1 without clock chip and with “memory counter” instead of the original 64k also for CX5M by Uwe Neisius

Convert Yamaha CX5M to MSX-2
pdf Convert Yamaha CX5M to MSX-2

pdf A complete BlueMSX profile of the Yamaha CX5MII by Uwe Neisius

Dutch article: MSX 2+ ombouw: de hardware
pdf MSX 2+ ombouw: de hardware

Patch by NYYRIKKI on 50/60 HZ selection on boot on a 825x/8280

Needed modifications to NMS8250 SUB-ROM:

#0422: 8C,3E
#3E8C: CD, 3C, 06, DB, AA, E6, F0, F6, 03, D3, AA, DB, A9, E6, 20, C8, AF, 32, E8, FF, C9

Functionality:
While boot logo is displayed, push “H”-key down untill beep to start in 50Hz mode, otherways 60Hz mode will be selected.

If you want to change also boot logo to 60Hz, put 0 to #2B56