Hi colourless people, you could try the following two things:
1. The V9958 requires a *clean* 5V on pin 21 to power the video outputs; If there is noise on this 5V, then this will result in noise on your video signals and degrades image quality. On the 5V which is used to power all digital circuits in the MSX there is a lot of noise, especially where the 5V enters a large digital chip like the V9958! So it is not a good idea, like described in the patch of Hans Oranje, to connect pin 21 with pin 58 (digital supply of V9958). It might be better to connect pin 21 to somewhere else in the MSX where you have 5V (with less noise). Like in the other patch that Laurens mentioned (for the 8245). Here they get the 5V from solderhole 26. Probably in the 8245 there is 5V here. This is not the case for the 825x: here there is a 10k pullup resistor to 5V (R166). So you might try connecting to the side of the resistor where the 5V is (and remove the 10k resistor because now the V9958 is outputting a wait signal on pin 26). The noise can also be seriously reduced by putting a decoupling capacitor (e.g. 100nF) between pin 21 and pin 20 (Analog GND). Keep the length of the leads of this capacitor as short as possible (<5mm). 2. for a NMS82xx the composite video signal is generated with a MC1377 chip. It uses the RGB info from the VDP, but also the Csync signal. Perhaps the timing for one of those signals has changed a little bit in the V9958. If this is the case, then the timing when the colour burst should happen in the cvbs signal, will also be shifted (and wrong). You can adjust this by adjusting the variable resistor VR301. It is located on the separate video board of the NMS825x next to the big black MC1377 chip. I don't know if it will help, but at least it is worth a try. Best regards, Jon _______________________________________________ MSX mailing list ([EMAIL PROTECTED]) Info page: http://lists.stack.nl/mailman/listinfo/msx
