Check the EEPROM. These units are not known for
no color. Be carefull doing this, as you can foul the unit
up badly. First use the menu, to see if you can actually
see the small vertical bar along with the dots across the
screen to adjust the color. Read this first!!!

http://repairfaq.ece.drexel.edu/sam/rcatune.htm#rcaver

Only, if the bar isn't there, enter the service menu, by
pressing menu, hold it, press power, release power
while still holding menu, then press volume up. You
will see P 01, left side, then V 00. Use volume up/
down to get to V 76. To reset the EEPROM:
Trick # 722

1.. Press and hold menu then press power and then press volume +
2.. Release menu
3.. Press menu (vertical will collapse don't panic)
4.. Press menu
5.. Press power
You may have restored the EEPROM, it's worked for me with some very weird
problems with the eeprom where I'd normally have replaced the eeprom.