Performed Furnace diagnostic on 1990 Rheem system. Upon my diagnostic system was experiencing intermittent behavior. 1. Found that circuitboard had Multiple burns and heat marks this could be an indication of a faulty board although cannot confirm it until new board is installed 2. Indoor blower motor has leaking oil from bearing and is over amp due to this, This can lead to the motor either locking up or overheating 3. Secondary motor control is becoming weak due to high amperage of fan 4. Condensate line are plumbed in correctly with the wrong material. 5. Duct work is not sealed correctly, This can cause lower Airflow and air Leakage 6. Static pressure was 0.90, Static pressure is the airflow of the system due to this being so high this Can cause complications with the heat exchanger overheating and Began to form cracks Recommendations- 1. After market Circuit board Is installed to solve intermittent behavior issue 2. Indoor blower motor is replaced due to oil leakage in high ampe