Saturday, December 16, 2006

Hitachi 51F510 Calibration

CRT-based displays are a dying breed. This is unfortunate because they still do some things better than even the best fixed-pixel TVs. Principal of these is blacks. A good CRT can render the smoothest and blackest blacks unmatched by even the best plasmas. You can't beat a display that can turn off areas of the image for a true black. Even plasmas must send a little current to every pixel to maintain response times. CRT does not have this limitation. After spending about 6 hours with a Hitachi 51F510, I can see why some people are hanging on to their older sets.

This TV was about 3 years old and had been well-cared for by its owner. He had removed the reflective screen cover, which not only causes major glare but it creates a color shift as well. He also lined the interior of the TV with light-absorbing Duvetyne. This dustless fabric prevents any internal reflections in a rear-pro cabinet and in some cases can really improve black level detail. He called me in to not only calibrate the set but also to work on the geometry and convergence.

The Hitachi has all the necessary controls in the Service Menu to adjust overscan and centering. I touched this up first then proceeded to the Convergence Menu. Rather than using the Magic Focus which sets the convergence hands-off, I did the 117-point adjustment with the TVs internal grid pattern. I worked out from center aligning red and blue to green. After 2 laps around the screen, I was done and the grid was tack-sharp.

Calibration followed with settings in both the User and Service Menus. There is full color management and color decoder adjustment available with color isolation. I was able to tame the red push pretty well and get the primaries right on spec. After adjusting the grayscale in the service menu, I touched up the color decoder again and I was finished. A long process but well worth it. This client had hoped to get some more life out of this TV rather than buy a new one and I was able to help him do that. CRTs do require a bit more work but the results are well worth the effort. I expect he'll be hanging on to this set for quite awhile longer!


otrick said...

I have this exact TV and to start I am using the Avia test disk but I am desparatly searching for someone to tell me the big secret of what the COLOR MANAGEMENT contols do exactly and what are they for or how are they used in calibrating the tv!?!

Hitatchi does not know, avia doesn't mention it, service manual doesn't explain...

The color DECODER controls are explained and are used in the Avia calibration to align the 3 primary colors but not the color management which has 6 color contol adjustments!

Chris Eberle said...

When I adjust the color management controls, I use a color analyzer to set the primaries and secondaries to the correct values. There is no way to do this without instruments that I'm aware of. You can set the color decoder very easily with this TV by shutting off colors and aligning with the color bars on Avia. If you perceive a red or green push after aligning the decoder, you could reduce red or green in the color management menu by a few clicks. I wouldn't suggest adjusting the secondaries by eye however.