What size screen do you have and you need to be 100% sure of the measurement. You can be within a few feet at that distance typically, but you do want an accurate measurement.
You should also give Christie Digital a call or send them an email. They are a top tier projection manufacturer and even if the projector is out of production, they may be able to direct you exactly where you need to go or give you some options.
Be aware, that from the throw distance calculator page, for that specific model, it lists all the different zoom lenses available. Once you find the exact one which works for your screen size and throw distance, then you can punch up a Google search for the exact model. eBay may very well be your friend at this point.
NOTE: It does look like the DHD675 and DHD670 both use the exact same lens options...https://www.projectorcentral.com/Christie-DHD675-E_Dual_Lamp.htm
The calculator is here:https://www.projectorcentral.com/Christie-DHD675-E_Dual_Lamp-projection-calculator-pro.htm
For example, a quick eBay search, if you do need the ultra long throw zoom lens...https://www.ebay.com/itm/Christie-projector-lens-133-104106-01-XX-DHD670-DWU675-DWU775-E-DHD675-DHD775-E-/292024283835
I guess if you only have about a 150" diagonal and you need that 100' throw distance, then you may need a 2x teleconverter. This is exactly where Christie may be able to answer your specific question because you may need an adapter from them (or others) along with the long throw lens.
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