|
| display. If the readings do not match, replace |
|
| thermocouple probe. |
| Power Supply | If strange or unusual behavior is experienced |
|
| such as a rolling of numbers, or lock up at a |
|
| given number, first check for a display circuit lock |
|
| up. This can be caused by a voltage spike or |
|
| surge in the incoming power lines. To eliminate |
|
| this condition remove power from the time/temp. |
|
| display by shutting off the main fan |
|
| switch for 15 seconds, or if display stays on, |
|
| (older models) circuit breaker interruption may be |
|
| required. This should eliminate the problem. If |
|
| the problem continues, jumper the two fuses in |
|
| the red wires leading from the 12.6 VAC trans- |
|
| former to the display on older units. |
|
| If this does not solve the problem, |
|
| it may be coming in through the |
|
| commercial power lines. Suggest |
|
| that customer contact his power |
|
| company for evaluation. |
| Temp Display | Perform the power supply check, |
| inaccurate, erratic, | the thermistor probe check, and |
| or inoperative | then perform the time/temp |
|
| simulator test. Refer to Section D for |
|
| instructions. Remember, when |
|
| using the time/temp simulator, |
|
| remove all the leads from the |
|
| back of the display except the 3 |
|
| power leads. After completion of |
|
| this test and if reinstalling display back |
|
| into the oven, the dip switches |
|
| must be reset for oven operation. |
S/N 2011821 & | Time Display | Perform all checks as in the above |
Above, See Pg. 45 | inaccurate, erratic, | evaluation. If the time check is |
| or inoperative | okay, refer to the next section - |
|
| optical encoder. |
| Optical Encoder | The above time/temp test should |
|
| have already been performed. |
|
| Remove the dust cover from the |
|
| gearmotor and inspect the coupling |
|
| and encoder disc. The coupling set |
|
| screws should be tight and not |
|
| slipping on the motor shaft or the |
|
| tach. generator shaft. The encoder |
|
| disc should be firmly attached to |
|
| the coupling and not warped. Check |
|
| the positioning of the optical |
|
| encoder disc. The disc should not |
|
| be touching the optical encoder |
|
| assembly and the encoder assembly |
|
| should be mounted so it is squarely |
|
| facing the coupling shaft. This is |
|
| to allow the infrared light beams to be |
|
| broken by the encoder disc. |
|
| If all this is okay, then replace the |
|
| optical encoder assembly. |
Impinger II - 1100 Series Service Manual - International | 33 | |
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