Hello everyone!
I want to remake the MSX2 to MSX2 + from Yamaha YIS-503III.
I replaced the VDP V9938 to V9958. I made a jumper on video processor 4,20,27 pin and 21,58 pin. Connect the signal WITE. Through impulse diode connected with Z80 (24pin) to V9958 (26pin).
After these changes without problems run games for MSX2 + but the display image is of poor quality (noise and ripple).
Please tell me how to improve the display image quality? http://www.youtube.com/watch?v=KpBNH6O6kLk
I went ahead and replaced the bios + basic.rom and ext.rom of MSX2 +.
Upgrade MSX2 to MSX2+ (Yamaha YIS-503III) КУВТ2
Daemos, thenx i check tomorrow 
Video is not visible but the picture quality was very good
Yep, he has used 220uF instead 220nF; but seems that it works
What's the resistor value used, the one suggested by Daemos (100K)?
Capacitor which was established in the store resistor exactly 100к. Can replace these two elements on the ceramic capacitor 0.1uF and install it parallel to the resistor R311.
There is another serious problem. This computer produced Yamaha for schools of the Soviet Union. After the installation of the BIOS from the MSX2 + about half the buttons do not match
I set the BIOS to "Sony F1-XV". Possible to change the new bios button on the keyboard to match? I can attach the old and the new bios.
Looks like you need to transplant some keyboard matrix stuff from the old BIOS to the new one