Bunn SA, STA, STFA DIGITAL BREW TIMER Late Models, Digital Brew Timer, SERVICE cont

Models: SA STFA ST STA STF

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DIGITAL BREW TIMER (Late Models)

SERVICE (cont.)

DIGITAL BREW TIMER (Late Models)

 

 

 

J2

 

 

J1

 

 

 

 

 

TL3

TL2

TL1

TL5

TL4

 

 

 

 

 

 

 

 

 

P2181

FIG. 16 DIGITAL BREW TIMER

Location:

The timer is located inside the front inspection panel. Some earlier models, with the new timer will have them located inside the rear panel.

Test Procedures:

NOTE: Do not remove or install wires while timer board is installed. Pressure applied to one side may cause damage to the board.

1.Disconnect the brewer from the power source and remove the front panel.

2.With a voltmeter, check the voltage across termi- nals TL1 and TL2 when the "ON/OFF" switch is in the "ON" position. Connect the brewer to the power source. The indication must be:

a.) 120 volts ac for two wire 120 volt models, three wire 120/208 volt models and three wire 120/240 volt models.

b.) 200 to 240 volts ac for two wire 200 or 240 volt models.

3.Disconnect the brewer from the power source.

If voltage is present as described, proceed to #4.

If voltage is not present as described, refer to the Wiring Diagrams and check the brewer wiring har- ness.

4.With a voltmeter, check the voltage across termi- nals TL1 and TL4 when the "ON/OFF" switch is in the "ON" position. Connect the brewer to the power source. The indication must be zero volts.

If voltage is as described, proceed to #5.

If voltage is not as described, disconnect the brewer from the power source and replace the timer.

5.With a voltmeter, check the voltage across termi- nals TL1 and TL4 when the "ON/OFF" switch is in the "ON" position. Connect the brewer to the power source and press the start switch. The indication must be:

a.) 120 volts ac for two wire 120 volt models, three wire 120/208 volt models and three wire 120/240 volt models.

b.) 200 to 240 volts ac for two wire 200 or 240 volt models.

If voltage is as described, the brew timer is operating properly. Reset the timer as required, to obtain the desired brew volume.

If voltage is not as described, test the START switch for operation before replacing the timer (see page 19). Test ON/OFF Switch if START Switch is functional (see page 17). If voltage is as described for both switches, disconnect the brewer from the power source and replace the timer.

Removal and Replacement:

NOTE: Do not remove or install wires while timer board is installed. Pressure applied to one side may cause damage to the board.

1.Remove the two #6-32 screws securing circuit board to component mounting bracket.

2.Remove circuit board and nylon spacers.

3.Remove all wires from the timer.

4.Attach all wires to the replacement timer board prior to installation to the component mounting bracket. Refer to FIG. 17 when reconnecting the wires.

5.Install new circuit board with nylon spacers to component mounting bracket.

6.Adjust the timer as described below.

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29251 011501

 

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Bunn SA, STA, STFA service manual DIGITAL BREW TIMER Late Models, Digital Brew Timer, SERVICE cont