The color wheels used early on in laser projectors were made from an organic phosphorous material which would deteriorate rather quickly. Later models used an inorganic phosphorous material which was much more durable and long lasting. Eventually the industry figured out how to make white from blue only and didn't need to produce green and red anymore. You can see in early model Casio M140's and A140's where there is a burnt line going around the color wheel. The Panasonic PT-RW630 was released back in 2014 so they may have still been using the organic color wheels in early production models so they could really only handle so much power before they would burn up. To get 6500 lumens output they likely needed to parallel the light engines to achieve such an output.
That is really odd, I've taken apart a130s and a140s, the only time I've seen a marked up phosphor wheel was when the inside of the machine was really dirty.
I've gone through several a140s and the only thing I noticed was at the diodes start to burn out after 10,000 hours or so. The red LED gets pretty gummed up too and loses brightness, but that seems to be more of an issue with just dust jamming up the heat sink. Also noticed that they used to use shims in the a140s on the diode block for alignment purposes that had a few diodes not fully clamped into place and probably died within the first few hours of use.
In the literature on this Panasonic series it's been said that the two chambers and the doubled up diodes was to compensate for diodes that lost brightness. It said that these machines can run maintenance free 24 hours a day 7 days a week for 10 years . They also mention the phosphor and the research they put into it.
Regarding the lumen output I don't think they need 64 diodes to hit 6,000 lumens. If we look at the XJ series V2 they only have eight diodes and hit the 3000 lumen mark. Bank One in this machine has four blocks of eight, even if each block is run at a moderate output, that's 32 diodes! I think that's more than enough to hit the 6000 plus mark.
I can't remember all the particulars of the article, I'll see if I can find in my history and the write-up on it.
I also read this is the first machine to use a single DLP chip that broke the 6,000 lumen mark.
Some of the used machines are being sold with 39,000 hours on them which leads me to believe that that what I read is true, that the second bank of diodes engage after the first bank loses brightness, which makes sense as the diodes are rated for 20,000 hours.
Overall a lot more engineering seems to have gone into these Panasonic machines versus the XJ and m series as well as other machines like BenQ that I've torn down to harvest parts.
The liquid cooling system was a nice touch, for the amount of light output this was a very quiet machine.
I pulled out six 120 mm fans plus two 60 mm fans for the phosphor wheels, and a ducted fan that was in place to cool the DLP chip.
Overall a great little harvest to go in my box of parts for future projects
to it 
