If you are constantly getting 90V at the raceways then there is something wrong with your
system. I would take a
meter to your
power feed to the dimmers and see what that reads. You shouldn't be loosing 25V-30V to cable runs (unless you are using severely under-rated cable). If your input
power is reading correct then chances are you have some setting wrong either in your dimmers or in your
console that is keeping the dimmers from going to full.
As far as the carbon
build up, it has nothing to do with the choice of lamp. A medium
bi-pin lamp (like the HX-601) is a medium
bi-pin lamp. It is possible that your fixtures may not be rated for certain wattages, but that would not cause extra carbon
build up. Using the HX-601 (FLK) in a
colortran shouldn't be a problem, it is a 575W lamp that should be well within the tolerances of the
fixture. However, in the future I would suggest the HX-604 (GLC) if you want to stay in the 575W lamp
category, as it has a much more modern and efficient
filament.
Inevitably, at some
point in every
fixture's life you will start to see carbon
build up on the lamps and in the lamp
base. Why? Because all the cycles of heating and cooling and the changing of lamps start to wear on the contacts in the lamp
base. As the connection between lamp and
base deteriorates you start to get arcing, and this produces the carbon deposits. Now, if you are getting
build up like this in the lamp
base you will start to go through lamps faster as it carbon deposits beget more carbon deposits. Many people perpetuate this because they see that a
fixture is out, and so they change the lamp. Then the
fixture works for a while, but while it is working carbon is building up on the lamp and eventually not electricity can pass, and thus another apparent burn out. So, if you open up your
fixture and there is a lot of
build up in the lamp
base then you NEED to replace the lamp
base. DON'T put new lamps in bad bases, it is a waste of money as the lamps weill become unuseable long before they should. Lamp bases are relatively in expensive and pretty easy to install.
I bet this is your issue, so I would look into picking up some new lamp bases and you should be in business.