My codes range between 00 and FF which is HEX for 0 and 255. More info is in the 2070SB service manual here: https://hardforum.com/data/attachment-files/2 … nc_FP2141SB.pdf
But you are out of luck there so put all settings the way they were originally and adjust the SCREEN knob on the flyback transformer. The SCREEN knob is basically a huge BRIGHTNESS setting, this is where it will allow you to go beyond your menus 0-100%. Here is a video that will help you:
https://www.youtube.com/watch?v=_Qi1D1delPk
They are adjusting FOCUS which is a knob that should be located near the SCREEN knob you need to adjust (the position of the knobs is showcased on Page 15, should be 3 knobs there). Get a very long (30cm?) insulated screwdriver, ideally all-plastic without any metal for adjusting (screwing) the knob. Instructions can be found on Page 13 of your manual, the problem is you cant follow them because you do not have their own service RS-232C adapter but it should do the trick even without that. You will need to take off the plastic casing and then have the monitor turned on which is not very safe so be careful not to touch anything inside. You will need a good battery light so you can located the knobs through the metal cage holes. Here is how the knobs usually look (on a different monitor): http://i.imgur.com/txGgyx6.jpg
You can replace Page 13 steps with something like this:
1. Set your brightness to 50 and contrast to 100. I am only assuming these are the default/center values for Diamondtrons (on Trinitrons these would be for example 31/90).
2. Set your resolution to 2048 x 1536 at 88 Hz (or whatever you use the most) and adjust the screen size with monitor buttons to be almost fullsize, and maintain correct aspect ratio.
3. Make sure your room is not too light, night time with a couple lights on is okay.
4. Use irfanview to display 100% black image, fullscreen
5. Adjust the knob (very carefully since its probably sensitive to even the slightest change) so that the black signal can be barely seen. Since your monitor is dark you should not see anything at first but when you start moving the knob in one direction (probably clockwise) the black should become dark grey. The sweetspot is where you can barely see the dark grey, where it is almost black (like 99% black).
Thats it. That should take care of your dark image problem. After this you will want to play with the color settings in both user and factory menus (gain, bias, etc). I suggest getting the old DTP94 calibration tool off eBay to help you with this process a little bit. It can help you with telling the current cd2 (=light output) and if you are spot on with the 9300K white coordinates for example which is impossible to tell with your eyes only.
NOTE 1: Sometimes the knobs are glued to prevent them from moving on their own. You will either see glue with your own eyes or feel it when you wont be able to turn the knob at first. If this will be the case you need to very carefully apply more turning pressure to break/crack the glue first. There should not be any damage if you accidentally turn the knobs too much in either direction since the ABL feature will prevent that but rather be careful, also not to slip the screwdriver.
NOTE 2: Personally I would cut a small hole (or 3, for focus knobs as well) in the plastic casing instead of taking the cover of, making it easier to adjust in the future. But you would need to know where exactly to make that hole and it might be impossible to see inside without taking off the plastic casing off at least once.
NOTE 3: And as you probably already know, the insides of the monitor are dangerous due to high voltage (up to 31,000 V I think) and some other things so do this only at your own risk and educate yourself on some basic safety rules first.