CurtPalme.com Home Theater Forum

[dropzone7]

Register to remove this ad. It's free!

I need to perform this procedure and have some questions. I have cut and pasted the steps listed in the guide from this site which was put together by KennyG. It looks pretty self explanatory and most of my questions are regarding exactly what to look for and how the voltmeter works. My questions or comments are in bold beside each step. Any help in clarifying would be appreciated.



Steps:

1) Allow 30 min warm up.

2) Turn color saturation in your video processing all the way down, otherwise grayscale can be thrown off by several hundred degrees. (Is this a function of the projector or a scaler, etc.? I'm just using an HD DVD player and an HD cable box. No scaler or processor of any kind.)

3) Set your processor to a minimum of line doubling, your can use anything above that also.

4) If your processor has brightness and contrast control set them to default. (Again, I have no other brightness or contrast controls that I know of except with the projector itself and perhaps gamma adjustment in my RTC2200 transcoder. I have turned gamma all the way down on that.)

5) Turn "Blue Focus Tracking" off...display focus pattern and adjust for sharpest focus, then turn "Blue Focus Tracking" back on. (This insures correct amount of projector defocusing) .

6) Set all "Kelvin" adjustments to default (50, both Black & White).

7) Open "Blanking" to max in all directions.

8) Set "Brightness" to 60.

9) Set "Contrast" to show 100ire window at normal level for your system (default?). (What would "normal" level be? Just before blooming or what? Can I set contrast using the Spyder and use the foot lamberts range method shown in the Greyscale calibration for Dummies thread?)

10) Set "AKB" test switch to test position. (Where is this switch? I have only seen the AKB as a menu option under the "info" menu of the signal entries list.)

11) Set your DMM (digital multimeter) to VDC and measure test points TP7404 (red G2) TP 7504 (green G2) and 7604 (blue G2) verify the voltage is 2.5 vdc +/-0.1 vdc...if not try small adjustments of "Contrast", if that doesn't help, call a service tech. (I know how to set the meter up but I'm not sure about how to take the measurements. Does the red (+) probe go in the test point and the black (-) probe goes to what? Ground to the metal chassis? Do I need to shut the projector down each time I move the probes from test point to test point?)

12) Adjust Black Bias to 50 (default) this is just a "rough setting".

13) Set "AKB" test switch back to Normal position.

14) Display AVIA "Verical Crossed Gray Ramp" pattern. (I have DVE, not AVIA. Which pattern from DVE HD Basics or the regular DVE HD version would be equivalent to this pattern?)

Note: Now begins the "adjustment loop" which you must repeat until G2 voltages no longer deviate from 2.5 vdc then readjusting and re-measuring during changes in the upcoming adjustments.

A) Begin Green Loop:

B) Adjust "Black Bias" to make TP7504 (GRN) read 2.5 vdc +/ 0.1vdc.

C) Look into the Green tube & see Gray ramps going vertically in opposite directions. Pay close attention to the dark edges of either ramp. Set "Bright Bias" to a point that just makes the dark outer edges of the ramps go black...the idea is to make the smallest amount of the ramp go black, make sure some of the ramp DOES go black.

D) Set "Brightness" to 0.

E) Look into the Green lens, you will now see a much darker looking ramp. Look at the edge of the ramp that goes from light to dark...Adjust "Bright Gain" to make the black edges of the ramps just meet at the center.

F) Set "Brightness" back to 60.

G) IF Green G2 still reads 2.5 vdc +/- 0.1 then exit Green adjustment loop...otherwise restart adjustment loop at step "B" (it's a good idea to run through this a second time anyway).

16) Begin Red adjustment loop, repeat steps B thru G.

17) Repeat steps B thru G for Blue gun.

18) From this point on, DO NOT adjust any of the Green gun's settings in the "White Ref" menu...this gun will serve as a reference by which Red & Blue guns are fine tuned for grayscale.

19) Calibrate grayscale using "Drive Control" for 100 ire window, and "Bright Bias" for the low end (30 ire) note that it will take several adjustment loops to get a flat grayscale, as these adjustment are dependent on each other.

20) Since you have probably had to change the G2 calibrated Red & Blue "Bright Bias" setting to get Red & Blue guns to track with the Green you must check your TP voltages again, if they are not at 2.5 vdc readjust "Black Bias" to get proper voltage.

21) Verify that "AKB" test switch makes only minor changes in screen appearance.

22) Readjust Brightness, Contrast & Kelvin for each memory slot.

[jarseneau]

[dropzone7]

Thanks for taking the time to answer all of my questions Jerry! It looks like you and Doug chimed in around the same time as he commented over in my regular thread. I'm hoping that I can get things back to where they were before but this is all virgin territory to me. While convergence and setup has been a challenge I have managed to come along pretty well on that. However, I never had to tweak G2 settings or do a greyscale before. I'm hoping this will be a GOOD learning experience unlike my last one with the system board.

[dropzone7]

I started this procedure today and my voltages are 2.47, 2.47 and 2.46. I tried adjustments to contrast as suggested and got not change. Is there anything I can do outside of calling a tech?

[jarseneau]

Oh boy, now you are totally in deep sh*t. There's no way to fix that..
oh, wait a minute, you don't need to do anything . The spec is that it should read 2.5 +/- .1, which is an acceptable range from 2.40 to 2.60.

[dropzone7]

[dropzone7]

Yeay! I finished the G2 procedure and what a difference that made. I went back and watched the video material on DVE to compare with what I was seeing prior to this procedure and it's just night and day. The green cast I was seeing is gone and the greyscale looks much better. Voltages remained in spec at the end of the adjustment and I'm now ready to tackle the greyscale adjustment.

[crestron]

Jerry
in "Look into the Green lens, you will now see a much darker looking ramp. Look at the edge of the ramp that goes from light to dark...Adjust "Bright Gain" to make the black edges of the ramps just meet at the center. "

How to correctly understand the meaning of "the black edges of the ramps just meet at the center"
the ramp from light to dark i see the Grey , "the black edges" which point is the correct location ?