Tests Power Supply, 2 RTD, Distribution Boards

•ERR LED toggles when a communication error is detected; it’s not unusual to see a flash, but regular flashing means communications problems.

•LED5 and LED6 used for programming/debugging; have no diagnostic function.

•LED7 When lit, the master control is executing a time or temp query operation on the front side.

•LED8 When lit, the master control is executing a time or temp query operation on the back side.

•HB LED is a heartbeat LED; toggles on / off to indicate processor is running.

•ACT LED flashes when it receives a valid communication packet; it should be flashing every few seconds or faster.

•LED3 Toggles if there is a communications error on a packet directed to the distribution board. Can flash on occasion; shouldn’t flash regularly.

•LED1 flashes if there is voltage being applied to one or more heaters on that distribution board; one or more plate is calling for heat.

Fig. 5: Distribution Board LED's

1.Disconnect power and check all terminals and connections for loose or disconnected wires.

2.Apply power and check for 5VDC at the power-in terminal on the distribution board and chassis ground.

1.Remove the leads from the suspect RTD and test for resistance. Selected temperatures and resistances are show in chart at right.

NOTE: After testing, reconnect all leads to their original positions.

1.Check for line voltage between the heater plate terminal on the board and the terminal block for the

RTD resistance chart

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