OK... Now I'm wondering... I went through the other night and did searches on the Max770(I swear my display board said Max771 but the FAQ lists it as Max770 in the dim display section) chip and looked carefully at the reference designs. I see how the BSP373 is utilized in the circuitry now and how the feedback on the MAX 770 is what provides the gain. I was able to identify that the chip referenced in the DImmer issue is actually setting the resistance on the feedback loop to provide the "boost" (Or so my understanding is). Anyway, I was not able to find a problem when poking around on things.

So... I put the unit back in the car and was driving for quite a bit when suddenly the display gets VERY bright again... not as bright as normal, I guess, but normal is in my mind. At first I thought it was an illusion but then I realized that i could see it during the day again somewhat through the red lens. When I was able to check, the 25V that I was reading was now reading 46V! The line to the right is still there and evident, but not as noticeable with a brighter display. I can live with this but think it's probably caused somehow by the lower voltage as the brighter the display got, the dimmer the line was. I replaced the BSP373 with a ST cross referenced part and the voltage still is staying at 47.

I'm wondering, though. I noticed in a few other posts that Tony, for example, had mentioned he thought his display was dimmer since installing the lighted buttons but I don't know if a voltage was taken to see if the voltage was still in the recommended 55-63 range. I guess I'm trying to figure out if this is just a resultant issue from the lighted buttons or is there still another problem. I am going to look at the 100nF capacitor mentioned as failing a bit closer when i return to work and perhaps replace that.

Of course I should be happy with what I have now, but would like things to at least be correct. Also... does anyone have a source for the AD8400 dimmer chips? I'm only finding the SOIC versions now which it was clearly pointed out they were not able to find when in production. I'm guessing the phone industry no longer uses them and they became available.