This is a Rheem model RHLA-HM3617JA Air Handler. It stopped running. The unit has proper power to it. I replaced the circuit board, in both the air handler and the condenser. The condenser board flashes all normal. The air handler circut board has 28 volts at the X13G. center, green/black wire. 0 volts at the top X13COM. brown lead. The bottom blue lead.. X13SPD has 1 volt. Fuse is good. 28 volts at the 24VAC terminal. The transformer appears ok. I replaced the variable speed motor with a new one from Rheem. I replaced the Tstat. The Tstat. is talking to the A/H.,bypass to engage motor does not work. Condenser works fine. I am now out of ideas....can anybody help??

Heating & Cooling - Quasar - HQ2052UH Air Conditioner