Philips 60PP9202, no color on main screen

I received a Philips 60" rear projection model 60PP9202 chassis number
DPTV305F from a friend who got it for free and attempted his own repairs.
Initially it had warped colors, AKA convergence problems. He replaced 2 resistors
with incorrect valued ones then gave up as he didn't want to pursue this TV any
longer.

I first off replaced both resistors with 6.8 ohm 1 watt and both STK392-120's,
based on what he told me of the initial problems this seemed the likely repair.
As I first turned it back on, it would power up and then shut off 12 seconds
later, power back up on its own and repeat. I finially figured out that he had 2
cables plugged into the wrong connectors on the Large Signal board.

Currently the picture is perfect, but black and white. Any menu, convergence
screen and the PiP are vivid color, yet the main picture is shown in black and
white. All 3 color tubes have good intensity, covering each one produces the
color shade expected on the screen. For some reason the main tuner is only
producing black and white images. One other symptom is the PiP will only show
the channel that is one the main screen, even though the channel numbers
change.

I have searched in vane for any schematic or service info beyond the STK's
and resistors. My suspicions are a defective IC that controls the main tuner or
possibly the loss of Chroma data supplied to this circuit. 

So my questions are...

1) Is there as service menu I can access to determine the chroma data loss?
Or perhaps a factory default reset other than the one in the convergence menu.

2) Any clue where to start troubleshooting for the main tuner color circuit?

FYI, my background is 25 years of aviation, test equipment and consumer
audio electronics.

I am very proficient in component repair and have a basic understanding of
TV theory, but with out a good schematic, I may as well be a novice.

Any help is welcome.