Older HAKKO FR-1418 BGA Rework Stations (prior to serial number ending 0064) used a different type of PID controller to regulate the top heater temperature. Situations can occur that cause the settings of the PID controller to become corrupt and will result in an oscillation of the top heater which is visible on the temperature plot of the HAKKO HMI application as shown in the following image.
To correct this issue, the default PID setting of 15/30 must be programmed into the system parameters. Please reference the HAKKO FR-1418 User Manual for information on how to access the system parameters.