I know you are going to cuss at me when I say this but take the 75 ft. lbs and pull it twice as hard to get the 150 lbs. Maybe someone will chime in and give real advise.
Do what I do buy 2. use one and when it breaks or needs recalibrating you have a back up. and when your repaired one comes back store it as your back up. With drawworks and large duplex mud pumps on drilling rigs we use 500lb Torque wrenches down to 50lb small ones, all having a back up. It may sound expensive till I end up where you are now. Then calculating the price per hour of one of my rigs are sitting idel because of a stupid torque wrench it becomes quite inexpensive!!
Is the broken one the clicker type? I've had them break or be out of calibration. I still use my old needle type, hasn't let me down for over 20 years now.
chacha--Glad you found what you needed, as a tip for the future here in Socal Americas tires shops have calibrated testers they use for liability protection. Every three mos. I take my 4 wrenches and they are kind enough to let me ck. them with no problem!:2thumbs: