Volvo Repair: no spark, electronic brain, wrecked cars

Question
hi,i have an 87 740gle i have had it 2 months.
it quit while going down the highway 1 month ago.
it has no spark and i dont know what else to try.i have replaced the following parts with used parts using discretion at the junk yard to pull parts from wrecked cars not
perfect condition cars:
distributor,coil,coil wire,power stage,cap,rotor,
electronic brain...it has power to the coil.
oh and i have checked the fuses.it does have an alarm,but i was told that it would not crank if that was the problem.it will crank fine ,but no spark. it has 214,000 miles and i noticed at the junkyard that alot of the non wrecked volvos are in the 200,000 mile area.is this a common problem?

Answer
well you replaced all parts that are in this system.the problem is how do you know all these parts were good parts.most common problem is the power stage.it will really need to be fault traced with a test light and a wiring diagram to see where the fault lies.