Do you have "correct" NTSC, PAL or SECAM into the device? Is the input terminated, AC coupled and filtered properly? Could the problem be downstream of the Decoder? Also, there are many register settings in the device that impact correct color along with proper composite input burst levels/freq. and possibly even correct SC/H phase.
- Check Color Lock Status bit (read) in Reg 88h
- Check Burst Ref Enable bit in Reg 02h s/b default (disabled)
- Check Reg 06h Color Killer settings and burst (on CVBS signal) levels. If burst in is too low and Reg 06h is set to default, then Color Kill could be on.
- Check to see that reg 0Ah is not set to "zero color" saturation
- Check Reg 1Ah to make sure that Color PLL is not in Reset and ACGC is enabled
- Check reg 01h to make sure that AGC is enable