I have four SB800 are the leds screens suppose to be the same brightness even after checking settings ?? One is quite a bit dimmer than the rest

If the display screen on your Boss MR1308UAB car stereo is completely black and you're unable to find a control setting for brightness, there may be a few possible causes and solutions to consider:

1. Check the backlight setting: Some car stereos have a separate setting to control the backlight or illumination of the display screen. Look for an "Illumination" or "Backlight" setting in the main menu or settings menu of the stereo. Adjust the setting to ensure that the backlight is turned on and set to an appropriate level.
2. Check the dimmer setting: Many car stereos have a dimmer function that adjusts the brightness of the display screen based on the ambient light conditions. Check if the dimmer setting is enabled and set to an appropriate level. If the dimmer is set to its lowest level or turned off, the display screen may appear black. Adjust the dimmer setting to increase the brightness.
3. Verify the connection: Ensure that the wiring connections between the car stereo and the vehicle's electrical system are secure. A loose or faulty connection could cause the display screen to appear black. Double-check the wiring harness and connections to make sure they are properly plugged in.
4. Reset the stereo: Try performing a system reset on the car stereo. This can help to clear any temporary glitches or issues that may be affecting the display screen. Refer to the user manual for instructions on how to perform a reset specific to your model.

I had a Sanyo LED TV and after 12 years of faithful operation it started going dim and got dimmer and dimmer each day
then the left 1/4 of the screen went black.
Your LED TV has a life span as does all new tv's and it may be at the end of its life span.
see https://www.reviewed.com/televisions/features/how-long-should-a-tv-last

To fix the dim brightness level, remove the battery and pull the plug out of the mains power. Leave it disconnected for at least 5 minutes then plug it back into mains power. You should find the brightness has retuned to normal. I have 3 of these Clock Radios and the picture attached shows the comparison between dim and normal. For some unknown reason they intermittently decide to dim themselves. This may be why Sony included a dimmer in the next model up ICF-C318. Anyway I hope this helps

Usually if you plug a lamp dimmer in, you can dim LEDs. The problem is that you may be using a switch-mode power supply which will give feedback and automatically increase the voltage. The manufacturer is probably the only safe way to get information as to whether this can be done.

hi Elle924.
this is all i could find out.
What kind of panel do you have - a LED or CCFL one? If it's CCFL then check the inverter board. The main board might be fine (changing the brightness settings changes the signal to the inverter board) but if the inverter board is faulty somewhere then the problem you described may be caused by it
or try this forum.
Why is my tv extremely bright Solved Other Consumer Electronics
or this one might help you.
White too bright in picture on Samsung LCD TV Forums
or even this link.
SAMSUNG LCD TV very bright screen Google Search

Hi,

It seems to be a hardware issue with the buttons. They are stuck or the rubber cushion under the button has gone bad. That's the reason they are getting pressed automatically. You may take to a local store for a small repair.

Regards,
Shrey

First of all, in general, dimmers (even at their highest setting) cause the lights to dim even a little bit. If you are doing a 1-for-1 comparison, you may notice a difference - but honestly, it shouldn't be THAT dramatic that you're able to notice it.

My first suggestion is to double-check the model number. There's a version of Diva with a "G" in the model number (DV-603PG-) which was designed with a lower-high-end light level than normal (designed to guarantee extra energy-savings).

If the model number checks out, my next suggestion is to upgrade to a spec-grade product (like an NT-600-WH). The commercia/specification grade products have a higher high-end than the residential grade products. It still will dim the lights a little bit, but will be better.

After that, I suggest calling tech support at 1-800-523-9466 for more suggestions. Its a free call and they're available 24/7.

Go to tv menu go to screen setting turn screen contrast to the max and screen brightness half midway point like 55.Tv real old like around ten years?Watches alots daily like 6 or 7 hrs a day?The tv CRT-(tv tube) might be to old,the radiation colors guns R,G,B insisde might not work as well as before.Have a reset setting in the colors setting?Go down to that press that,to restting for the factory colors setting.Or tries add more blue,a bit less green and red,see how that turn out?

Hello,

you can try windows up date, or check the control panel, locate display and check the Brightness settings.

It is also possible that part of your screen bulb is dead, that's why one part is dimmer.

But there is no drivers that will make your screen bright.

Take care.

The sb600 needs to be able to see the preflashes of the sb800, so this is probably caused by one of two things.  The first thing I'd check is whether or not the light sensor on the side of the sb600 was covered, blocked, or facing away from the sb800.  I've had problems outdoors when I forgot to have the light sensor face the camera.
If the sensor was facing the camera, it is possible that the flashes didn't have a good line of sight to each other.  That normally shouldn't matter, but if there is a high ceiling and lots of people, it could be the case.  I don't know if it will help, but in any case I would recommend using a StoFen Omnibounce on the sb800 to increase the likelihood that the light finds a direction where a surface to bounce off of is found.  
Good luck.