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G2 RGB values update on G90 ?

post #1 of 8
Thread Starter 
Quick question : does somebody know if there is a chance to be able to update the R/G/B G2 settings on the Sony VPH-G90U ?
Is there a hidden menu to access to these parameters ? If not, where those values are stored within the Dallas DS1245Y chip ?

Thx

John
post #2 of 8
I am also interested in this.
post #3 of 8
John, it seems that the G90 uses the ABG function to establish the G2 setting. What I do is to turn on the projector and let it run with ABG enabled for twenty minutes. After that, the ABG is calibrated and the G2 value seems to be updated. If you turn off ABG after that, the G2 setting seems to remain constant. If you keep ABG enabled a new G2 will be established every time the G90 is powered on and let run for twenty minutes.

I usually turn off ABG just before calibrating gray scale. Then before redoing grays scale in the future I let ABG run again for 20 minutes.

If you want to find the settings in the Dallas chip I suppose you could compare a before and after with respect to ABG on and off. This way you could locate the addresses in the Dallas chip. I guess you would have to pull the Dallas chip twice though.

craigr
post #4 of 8
Also, have you ever noticed that when you change the PE board, that you MUST toggle ABG on and off. Otherwise the G2 settings will be totally wrong

craigr
post #5 of 8
Thread Starter 
Thanks for the info Craig,

I was thinking about an hidden Sony Service Menu to access to the G2 routh settings (in case of changing tubes on the unit for example) with ABG OFF. I sometimes noticed some 10-20IRE black crush after tubes replacement that Bias adjustments can't correct (while keeping good Contrast).

In fact, I'm just looking for a G2 adjustment procedure the way that G70 does (for firmware prior to 1.1). Since Sony removed this G2 adjustment they should still have some hidden way to get access to...

Accessing the Dallas NOVSRAM content is one way to go, yes but not really convenient when adjusting the G2 settings since it would need numerous content changes...

John
post #6 of 8
John, I don't think there is any way to fire up your tubes after replacement on the G90 than to turn on ABG.

I have to do it every once in a while on the stack before calibration.

The only "hidden" part I know of is the Gamma correction feature?

Cliff
post #7 of 8
Hey John,

I was just looking at the service manual section 5-2-4. There are instructions on "properly" adjusting the ABL circuit... I bet you could manipulate that procedure to alter the G2 values when ABL is cycled. Check it out and let us know what you think.

craigr
post #8 of 8
Thread Starter 
Thanks for the point Craig !

I'll check that and report back.

John
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