For this job, I was showing up to a repair. Upon checking the system. It was clear that the board was having electrical issues and intermittently going in and out. After checking the end-user and seeing that it was over amping immediately check the heat exchanger. Heat exchanger had multiple Issues with the eyelits coming apart and moisture leaking through as well as the cells of the heat exchanger coming off of the furnace wall. Because of this, the supervisors been called out to diagnose the problem further and come up with solutions. Replacement is definitely the best option with a system this old .